<PAGE>
 
                                                                   EXHIBIT 10(T)


                             AMENDED AND RESTATED
                          REVOLVING CREDIT AGREEMENT

                         DATED AS OF DECEMBER 4, 1998

                                     AMONG

                        AMERICAN DENTAL PARTNERS, INC.,

                           THE LENDERS PARTY HERETO

                                      AND

                              FLEET NATIONAL BANK

                                   AS AGENT

                                      AND

                               BANKBOSTON, N.A.

                                  AS CO-AGENT
                                  -----------
<PAGE>
 
                               TABLE OF CONTENTS
                               -----------------

<TABLE> 
<CAPTION> 
                                                                                          PAGE
<S>                                                                                       <C> 
Section 1.   Definitions                                                            1
             1.1    Certain Definitions                                                    1
             1.2    Accounting Terms                                                      13
             1.3    Rules of Interpretation                                               13
 
Section 2.   Revolving Credit Loans; Letters of Credit                                    14
             2.1    Amount                                                                14 
             2.2    Revolving Credit Note                                                 14 
             2.3    Lending Office                                                        14 
             2.4    Requests For Revolving Credit Loans                                   14 
             2.5    Letters of Credit                                                     14 
             2.6    Maturity of Revolving Credit Loans                                    16 
             2.7    Termination or Reduction of Commitment                                16 
             2.8    Several Obligations                                                   17  
 
Section 3.   [Intentionally Omitted]                                                      17
 
Section 4.   Interest Rates; Fees; Payments                                               17
             4.1    Interest Rates                                                        17
             4.2    Commitment Fee                                                        18
             4.3    Letter of Credit Fees                                                 18
             4.4    Certain Notices                                                       19
             4.5    Non-Receipt of Funds by the Agent                                     19
             4.6    Sharing of Payment; Waiver of Enforcement Without Consent,              
                    Etc                                                                   20
             4.7    Minimum and Maximum Amounts                                           21
             4.8    Computations                                                          21
             4.9    Manner and Place of Payment                                           21
             4.10   Pro Rata Treatment.                                                   22
             4.11   Payments Due on Days Other than Banking Days                          22
             4.12   Additional Costs                                                      22
             4.13   Limitation on Types of Loans                                          24
             4.14   Illegality                                                            24
             4.15   Substitute Prime Rate Loans                                           24
             4.16   Compensation.                                                         24
             4.18   Optional Prepayments                                                  26
             4.19   Mandatory Prepayments                                                 26 
 
Section 5.   Security.                                                                    26
             5.1    Security Interests                                                    26
 
Section 6.   Conditions Precedent                                                         27
             6.1    Conditions to all Loans and Letters of Credit                         27
</TABLE> 
<PAGE>
 
<TABLE> 
<S>                                                                                       <C> 
Section 7.   Representations and Warranties                                               29
             7.1    Corporate Status                                                      29
             7.2    No Violation                                                          29
             7.3    Corporate Power and Authority                                         30
             7.4    Enforceability                                                        30
             7.5    Consents or Approvals                                                 30
             7.6    Financial Statements                                                  30
             7.7    No Material Change                                                    31
             7.8    Litigation                                                            31
             7.9    Compliance with Other Instruments; Compliance with Law                31
             7.10   Subsidiaries                                                          31 
             7.11   Investment Company Status; Limits on Ability to Incur
                    Indebtedness                                                          31
             7.12   Title to Property                                                     32 
             7.13   ERISA                                                                 32 
             7.14   Taxes                                                                 32 
             7.15   Environmental Matters                                                 32 
             7.16   Intellectual Property                                                 33 
             7.17   Level of Borrowing                                                    33 
             7.18   Malpractice Insurance                                                 33 
             7.19   Year 2000 Risk                                                        33 
             7.20   Disclosure.                                                           34  
 
Section 8.   Affirmative Covenants                                                        34
             8.1    Use of Proceeds.                                                      34  
             8.2    Conduct of Business; Maintenance of Existence.                        34  
             8.3    Compliance with Laws                                                  34  
             8.4    Insurance                                                             34  
             8.5    Financial Statements, Etc.                                            35  
             8.6    Notice of Default.                                                    36  
             8.7    Environmental Matters                                                 37  
             8.8    Taxes and Other Liens                                                 38  
             8.9    ERISA Information                                                     38  
             8.10   Inspection                                                            38 
             8.11   Certain Obligations Respecting Subsidiaries                           38 
             8.12   Further Assurances                                                    39  
 
Section 9.   Negative Covenants                                                           39
             9.1    Transactions with Affiliates                                          40
             9.2    Consolidation, Merger or Acquisition                                  40 
             9.3    Disposition of Assets                                                 41 
             9.4    Indebtedness                                                          41 
             9.5    Guarantees                                                            42 
             9.6    Liens                                                                 42 
             9.7    Restricted Payments                                                   43 
             9.8    Investments                                                           43 
             9.9    ERISA                                                                 44 
             9.10   Fiscal Year                                                           44 
</TABLE>           
                   
<PAGE>
 
<TABLE>
<S>                                                                                       <C>
Section 10.    Financial Covenants                                                        44
               10.1  Debt Coverage                                                        45
               10.2  Fixed Charges Coverage                                               45
               10.3  Minimum Net Worth.                                                   45

Section 11.    Events of Default                                                          45
               11.1  Events of Default                                                    45
               11.2  Remedies Upon an Event of Default                                    47
 
Section 12.    The Agent And The Co-Agent                                                 47
               12.1  Appointment, Powers and Immunities                                   47
               12.2  Reliance                                                             48
               12.3  Defaults                                                             49
               12.4  Rights as a Lender.                                                  49
               12.5  Events                                                               49
               12.6  Non-Reliance on Agent or the Co-Agent and Other Lenders.             50
               12.7  Failure to Act                                                       50
               12.8  Removal of Agent or Co-Agent.                                        50
               12.9  Collateral Sub-Agents                                                51 
 
Section 13.    General.                                                                   51
               13.1  Amendments, Etc.                                                     51 
               13.2  Notices, Etc.                                                        51 
               13.3  No Waiver; Remedies                                                  52 
               13.4  Right of Set-off                                                     52 
               13.5  Expenses; Indemnification                                            52 
               13.6  Successors and Assigns.                                              53 
               13.7  Severability.                                                        55 
               13.8  Governing Law                                                        55 
               13.9  Waiver Of Jury Trial.                                                55 
               13.10 Venue, Consent To Service Of Process.                                56
               13.11 Additional Lenders.                                                  56
               13.12 Pledge.                                                              56
               13.13 Headings                                                             57
               13.14 Counterparts.                                                        57
               13.15 Confidentiality                                                      57
               13.16 Amendment and Restatement.                                           57 
</TABLE>                                                        
                                                                
EXHIBITS:                                                       
-------- 

A - Revolving Credit Note
B - Security Agreement
C - Subsidiary Security Agreement
D - Stock Pledge Agreement
E - Subsidiary Guaranty
F - Compliance Certificate
G - Assignment and Joinder Agreement
<PAGE>
 
SCHEDULES:
--------- 

A -    Disclosure Schedule
1 -    Applicable Margin and Commitment Fees
2 -    Commitments of the Lenders
         
     
<PAGE>
 
                AMENDED AND RESTATED REVOLVING CREDIT AGREEMENT


     THIS AMENDED AND RESTATED REVOLVING CREDIT AGREEMENT, dated as of December
4, 1998, by and among AMERICAN DENTAL PARTNERS, INC., a Delaware corporation
(the "Borrower"), having its principal place of business and chief executive
      --------                                                              
offices at 301 Edgewater Place, Suite 320, Wakefield, Massachusetts 01880; FLEET
NATIONAL BANK, a national banking association, with its principal place of
business at Fleet Center, One Federal Street, Boston, Massachusetts 02110
(together with its successors, "Fleet"); each other lender which may from time
                                -----                                         
to time become a signatory hereto (individually, together with its successors as
well as Fleet, a "Lender" and collectively, together with their respective
                  ------                                                  
successors, the "Lenders"); Fleet, as agent for the Lenders (in such capacity,
                 -------                                                      
together with its successors in such capacity, the "Agent"); and BANKBOSTON,
                                                    -----                   
N.A. as co-agent for the Lenders (in such capacity, together with its successors
in such capacity, the "Co-Agent")
                       --------  

     WHEREAS, the Borrower and Fleet are parties to a Revolving Credit Agreement
dated as of April 24, 1997 (as amended, modified or supplemented from time to
time, the "Original Credit Agreement");
           -------------------------   

     WHEREAS, the Borrower and Fleet desire to amend and restate the Original
Credit Agreement in its entirety in order to amend and modify certain terms and
provisions of the Original Credit Agreement as set forth herein.

     NOW, THEREFORE, in consideration of the premises and for other good and
valuable consideration, the receipt and adequacy of which are hereby
acknowledged, the parties hereto agree as follows:

Definitions.

     Certain Definitions.  The following terms are used herein with the meanings
     -------------------                                                        
assigned to them below:

     "Accountants" shall mean KPMG Peat Marwick LLP, or another of the so-called
      -----------                                                               
"big five" accounting firms or, subject to the prior approval of the Majority
Lenders, other certified public accountants selected by the Borrower.

     "Additional Costs" shall have the meaning set forth in Section 4.12.
      ----------------                                                   

     "Adjusted EBITDA" shall mean an amount equal to  (i) EBITDA of the Borrower
      ---------------                                                           
for the twelve month period then ended less (ii) EBITDA for each Acquired
                                       ----                              
Company for such fiscal period plus (iii) EBITDA for each Acquired Company on a
                               ----                                            
pro forma basis for the twelve months preceding the end of such fiscal period,
provided, however, that the EBITDA for Acquired Companies may be adjusted, for
--------  -------                                                             
certain identified one-time savings.

     "Affiliate" shall mean, with respect to any specified Person (the
      ---------                                                       
"specified person"), any Person directly or indirectly controlling, controlled
 ----------------                                                             
by or under direct or indirect common control with, the specified person and,
without limiting the generality of the foregoing, includes (i) any director,
officer or, in the case of a limited liability company, manager of the specified
person or any Affiliate of the specified person, (ii) any such director's,
officer's or manager's parent, spouse, child or child's spouse (a "relative"),
(iii) any group acting in concert, of one or more such directors, officers,
managers, relatives or any combination thereof (a "group"), (iv) any
<PAGE>
 
Person controlled by any such director, officer, manager, relative or group in
which any such director, officer, manager, relative or group beneficially owns
or holds 10% or more of any class of voting securities or a 10% or greater
equity or profits interest and (v) any Person or group which beneficially owns
or holds 10% or more of any class of voting securities or membership interests
or a 10% or greater equity or profits interest in the specified person. For the
purposes of this definition, the term "control" when used with respect to any
specified person means the possession, directly or indirectly, of the power to
direct or cause the direction of the management or policies of such specified
person, whether through the ownership of voting securities, by contract or
otherwise.

     "Agreement" shall mean this Amended and Restated Revolving Credit
      ---------                                                       
Agreement.

     "Applicable Lending Office" means, for each Lender and for each Type of
      -------------------------                                             
Loan, the Lending Office of such Lender (or of an affiliate of such Lender)
designated for such Type of Loan on Schedule 3 hereof or such other office of
                                    ----------                               
such Lender (or of an affiliate of such Lender) as such Lender may from time to
time specify to the Agent and the Borrower as the office by which its Loans of
such Type are to be made.

     "Applicable Margin" shall mean, in respect of any Type of Loan, the amount
      -----------------                                                        
for such Type of Loan determined pursuant to Schedule 1 attached hereto, it
                                             ----------                    
being agreed that any change in the Applicable Margin shall be effective three
(3) days after the date upon which the Agent has received a duly executed and
completed Compliance Certificate evidencing the applicable Total Debt/Adjusted
EBITDA Ratio.

     "Banking Day" shall mean any day on which commercial banks settle payments
      -----------                                                              
in New York or London with respect to any payment obligation which is a LIBOR
Loan or New York with respect to any other payment obligation, excluding
Saturday and Sunday and excluding any other day which in The Commonwealth of
Massachusetts is a legal holiday or a day on which banking institutions are
authorized by law to close.

     "Borrower Group Property" shall mean any real property owned, occupied, or
      -----------------------                                                  
operated by the Borrower or any of its Subsidiaries.

     "Capital Expenditures" shall mean all expenditures for fixed assets made by
      --------------------                                                      
the Borrower or any of its Subsidiaries which are capitalized, including
expenditures related to a Capital Lease, but excluding all expenditures incurred
in connection with any Permitted Acquisition.

     "Capital Lease" shall mean, as to any Person, any lease which is
      -------------                                                  
capitalized on the balance sheet of such Person in accordance with GAAP.

     "Capital Lease Obligations" shall mean, as to any Person, the amount of the
      -------------------------                                                 
obligations of such Person to pay rent or other amounts under a lease of (or
other agreement conveying the right to use) real and/or personal property which
obligations are classified and accounted for as a capital lease on a balance
sheet of such Person in accordance with GAAP (including Statement of Financial
Accounting Standards No. 13, as amended, of the Financial Accounting Standards
Board).

     "Closing Date" shall mean the first date on which the conditions set forth
      ------------                                                             
in Section 6.1 have been satisfied and any Loans are to be made or any Letters
of Credit are to be issued hereunder.
<PAGE>
 
     "Code" shall mean the Internal Revenue Code of 1986, as amended, or any
      ----                                                                  
successor statute.

     "Collateral" shall have the meaning given that term in the Security
      ----------                                                        
Agreement

     "Commitment"  In relation to any particular Lender, the maximum dollar
      ----------                                                           
amount which such Lender has agreed to loan to the Borrower or make available to
the Borrower upon the terms and subject to the conditions of this Agreement,
initially as set forth on Schedule 2 attached hereto, as such Lender's
                          ----------                                  
Commitment may be modified pursuant hereto and in effect from time to time.
Schedule 2 shall be amended from time to time, with prior notice to the
----------                                                             
Borrower, to reflect any changes in the Commitments of the Lenders.

     "Commitment Percentage"  In relation to any particular Lender, the
      ---------------------                                            
percentage which such Lender's Commitment represents of the aggregate
Commitments of all the Lenders, initially as set forth on Schedule 2 attached
                                                          ----------         
hereto, as such Lender's Commitment Percentage may be modified pursuant hereto
and in effect from time to time.  Schedule 2 shall be amended from time to time
                                  ----------                                   
to reflect any changes in the Commitment Percentages of the Lenders.

     "Contractual Obligation" shall mean, as to any Person, any provision of any
      ----------------------                                                    
security issued by such Person or of any agreement, instrument or other
undertaking to which such Person is a party or by which it or any of its
property is bound.

     "Controlled Group" shall mean all members of a controlled group of
      ----------------                                                 
corporations and all trades or businesses (whether or not incorporated) under
common control which, together with the Borrower, are treated as a single
employer under Sections 414(b) or 414(c) of the Code.

     "Default" shall mean any condition or event that constitutes an Event of
      -------                                                                
Default or that with the giving of notice or lapse of time or both would, unless
cured or waived, become an Event of Default.

     "Deposited Funds" shall have the meaning set forth in Section 4.6.
      ---------------                                                  

     "EBITDA" shall mean, for any fiscal period, an amount equal to Net Income
      ------                                                                  
for such period, plus each of the following (without duplication), to the extent
deducted in computing such Net Income:  (i) Interest Expense, (ii) taxes
accrued, (iii) depreciation, and (iv) amortization of goodwill and other
intangibles.

     "Environmental Laws" shall mean all federal, state, local and foreign laws,
      ------------------                                                        
and all regulations, notices or demand letters issued, promulgated or entered
thereunder, relating to pollution or protection of the environment and to
occupational health and safety, including, without limitation, laws relating to
emissions, discharges, releases or threatened releases of pollutants,
contaminants, chemicals, or Hazardous Substances into the environment
(including, without limitation, ambient air, surface water, ground water, land
surface or subsurface strata) or otherwise relating to the manufacture,
processing, distribution, use, treatment, storage, disposal, transport or
handling of pollutants, contaminants, chemicals or Hazardous Substances.

     "ERISA" shall mean the Employee Retirement Income Security Act of 1974, as
      -----                                                                    
amended, or any successor statutes.

     "Event of Default" has the meaning set forth in Section 11.1.
      ----------------                                            
<PAGE>
 
     "Excluded Property" shall mean (i) any property of the Borrower or its
      -----------------                                                    
Subsidiaries the purchase price of which was, or in the future may be, financed
with Indebtedness permitted by Sections 9.4(b), 9.4(c), 9.4(e), or 9.4(f) and
(ii) real property of the Borrower or its Subsidiaries the purchase price of
which was financed with Indebtedness listed on Schedule A or assumed by the
Borrower in connection with a Permitted Acquisition and (iii) leasehold
interests in any real property.

     "Extension of Credit" shall mean the making of any Loan or the issuance of
      -------------------                                                      
any Letter of Credit.

     "Federal Funds Rate" means, for any day, the rate per annum (rounded
      ------------------                                                 
upwards, if necessary, to the nearest 1/100th of 1%) equal to the weighted
average of the rates on overnight Federal funds transactions with members of the
Federal Reserve System arranged by Federal funds brokers on such day, as
published by the Federal Reserve Bank of New York on the Banking Day next
succeeding such day, provided that (a) if such day is not a Banking Day, the
Federal Funds Rate for such day shall be such rate on such transactions on the
next preceding Banking Day as so published on the next succeeding Banking Day,
and (b) if no such rate is so published on such next succeeding Banking Day, the
Federal Funds Rate for such day shall be the average rate charged to Fleet on
such day on such transactions as determined by the Agent.

     "Financial Statement Date" shall mean December 31, 1997.
      ------------------------                               

     "Fixed Charges" shall mean, for any fiscal period, the sum of (i) the
      -------------                                                       
amount of the scheduled installments of principal payable in respect of
Indebtedness of the Borrower and its Subsidiaries during such period, plus (ii)
                                                                      ----     
Interest Expense for such period, plus (iii) the tax provision of the Borrower
                                  ----                                        
and its Subsidiaries paid or required to be paid in cash for such period, plus
                                                                          ----
(iv) Maintenance Capital Expenditures made by the Borrower and its Subsidiaries
during such period, plus (v) Rental Payments, plus (vi) distributions to
                    ----                      ----                      
stockholders permitted by the Agreement.

     "Fleet" means Fleet National Bank and its successors.
      -----                                               

     "Funding Standard Controlled Group" shall mean all members of a controlled
      ---------------------------------                                        
group of corporations and all trades or businesses (whether or not incorporated)
under common control which, together with the Borrower, are treated as a single
employer under Sections 414(b), 414(c), 414(m) or 414(o) of the Code.

     "GAAP" shall mean accounting principles generally accepted in the United
      ----                                                                   
States applied on a consistent basis.

     "Governmental Approval" shall mean any authorization, consent, order,
      ---------------------                                               
approval, license, lease, ruling, permit, tariff, rate, certification,
validation, exemption, filing or registration by or with, or notice to, any
Governmental Authority.

     "Governmental Authority" shall mean any federal, state, municipal or other
      ----------------------                                                   
governmental department, commission, board, bureau, agency, court, tribunal or
other instrumentality, domestic or foreign, and any arbitrator.

     "Guarantee" by any Person shall mean any obligation, contingent or
      ---------                                                        
otherwise, of such Person directly or indirectly guaranteeing any Indebtedness
or other obligation of any other Person and, without limiting the generality of
the foregoing, any obligation, direct or indirect, contingent or otherwise of
such Person (a) to purchase or pay (or advance or supply funds for the 
<PAGE>
 
purchase or payment of) such Indebtedness or other obligation (whether arising
by virtue of partnership arrangements, by agreement to keep-well, to purchase
assets, goods, securities or services, to take-or-pay, or to maintain financial
statement conditions or otherwise) or (b) entered into for the purpose of
assuring in any other manner the obligee of such Indebtedness or other
obligation of the payment thereof or to protect such obligee against loss in
respect thereof (in whole or in part); provided that the term Guarantee shall
                                       --------
not include endorsements for collection or deposit in the ordinary course of
business. The term "Guarantee" used as a verb has a corresponding meaning.

     "Guarantors" shall mean, collectively, PDHC, Ltd., a Minnesota corporation,
      ----------                                                                
Texas Dental Partners, Inc., a Texas corporation, American Dental Partners of
Louisiana, Inc., a Delaware corporation, Smileage Dental Care, Inc., a Wisconsin
corporation, Soster Dental, Inc., a Pennsylvania corporation, American Dental
Partners of Wisconsin, Inc., a Delaware corporation, Apple Park Associates,
Inc., a Delaware corporation, Orthocare, Ltd., a Minnesota corporation,
Innovative Practice Concepts, Inc., an Arizona corporation, Family Care Dental
Centers, Inc., a Wisconsin corporation, American Dental Professional Services,
Inc., a Delaware corporation, American Dental Partners of Virginia, Inc., a
Delaware corporation, and American Dental Partners of Maryland, Inc., a Maryland
corporation, any other Person that becomes a party to a Subsidiary Guaranty.

     "Guarantors' Documents" shall mean the Subsidiary Guaranties and the
      ---------------------                                              
Subsidiary Security Agreements.

     "Hazardous Substances" shall mean all hazardous and toxic substances,
      --------------------                                                
wastes or materials, hydrocarbons (including naturally occurring or man-made
petroleum and hydrocarbons), flammable explosives, urea formaldehyde insulation,
radioactive materials, biological substances, PCBs, pesticides, herbicides and
any other kind and/or type of pollutants, or contaminates and/or any other
similar substances or materials which, because of toxic, flammable, explosive,
corrosive, reactive, radioactive or other properties that may be hazardous to
human health or the environment, are included under or regulated by any
Environmental Laws.

     "Indebtedness" of any Person at any date shall mean, (a) all indebtedness
      ------------                                                            
of such Person for borrowed money (excluding current trade liabilities which
shall include payables to affiliated dental groups incurred in the ordinary
course of business and payable in accordance with customary practices), or which
is evidenced by a note, bond, debenture or similar instrument, (b) all
obligations of such Person under leases that are treated as capitalized leases
in accordance with GAAP, (c) all obligations of such Person in respect of
bankers acceptances issued or created for the account of such Person, and all
reimbursement obligations (contingent or otherwise) of such Person in respect of
any letters of credit issued for the account of such Person to the extent not
secured by cash and without duplication of any underlying Indebtedness, (d) all
liabilities secured by any Lien on any property owned by such Person even though
such Person has not assumed or otherwise become liable for the payment thereof,
and (e) without duplication, all Guaranties.

     "Intellectual Property" shall have the meaning specified in Section 7.16.
      ---------------------                                                   

     "Interest Expense" shall mean, for any fiscal period, the sum (determined
      ----------------                                                        
without duplication) of the aggregate amount of interest required to be paid
during such period on Indebtedness of the Borrower and its Subsidiaries (on a
consolidated basis), including the interest portion of payments under Capital
Lease Obligations.
<PAGE>
 
     "Interest Period" shall mean, with respect to any LIBOR Loan, the period
      ---------------                                                        
commencing on the date such LIBOR Loan is made or converted from a Prime Rate
Loan or the last day of the next preceding Interest Period with respect to such
LIBOR Loan and ending on the numerically corresponding day in the first, second,
third or sixth calendar month thereafter, as the Borrower may select as provided
in Section 4.4, except that each such Interest Period which commences on the
last Working Day of a calendar month (or on any day for which there is no
numerically corresponding day in the appropriate subsequent calendar month)
shall end on the last Working Day of the appropriate subsequent calendar month.

     Notwithstanding the foregoing: (i) no Interest Period may end after the
Maturity Date; (ii) each Interest Period which would otherwise end on a day
which is not a Working Day shall end on the next succeeding Working Day (or, if
such next succeeding Working Day falls in the next succeeding calendar month, on
the next preceding Working Day); and (iii) no Interest Period shall have a
duration of less than one month and, if the Interest Period therefor would
otherwise be a shorter period, such LIBOR Loan shall not be available hereunder.

     "Investments" shall mean, with respect to any Person (the "Investor"), any
      -----------                                                              
investment by the Investor in any other Person, whether by means of share
purchase, capital contribution, purchase or other acquisition of a partnership
or joint venture interest, loan, time deposit, demand deposit or otherwise.

     "Issuing Bank" shall mean Fleet.
      -------------                  

     "Letter of Credit" shall mean any standby letter of credit issued by the
      ----------------                                                       
Issuing Bank for the account of the Borrower as provided in this Agreement.

     "Letter of Credit Usage" shall mean, at any time, the aggregate at such
      ----------------------                                                
time of (a) the maximum amount then available to be drawn under all outstanding
Letters of Credit, and (b) all then unreimbursed drawings under any Letters of
Credit.

     "LIBOR Lending Office" shall mean, initially, the Agent's office at One
      --------------------                                                  
Federal Street, Boston, Massachusetts 02110 and, thereafter, such other office
of the Agent as shall be making or maintaining LIBOR Loans.

     "LIBOR Loan" shall mean, at any time, that principal amount of the Loans,
      ----------                                                              
the interest on which is determined at such time on the basis of rates referred
to in the definition of "LIBOR Rate".

     "LIBOR Rate" shall mean with respect to any Interest Period pertaining to a
      ----------                                                                
LIBOR Loan, the rate per annum (rounded upwards, if necessary, to the nearest
1/32 of one percent) as determined on the basis of the offered rates for
deposits in U.S. dollars, for a period of time comparable to the applicable
LIBOR Loan which appears on the Telerate page 3750 as of 11:00 a.m. London time
on the day that is two London Banking Days preceding the first day of such LIBOR
Loan; provided, however, if the rate described above does not appear on the
Telerate System on any applicable interest determination date, the LIBOR rate
shall be the rate (rounded upwards as described above, if necessary) for
deposits in dollars for a period substantially equal to the interest period on
the Reuters Page "LIBO" (or such other page as may replace the LIBO page on that
service for the purpose of displaying such rates), as of 11:00 a.m. (London
time), on the day that is two (2) London Banking Days prior to the beginning of
such interest period. "Banking Day" shall mean, in respect of any city, any date
on which commercial banks are open for business in that city.
<PAGE>
 
     If both the Telerate and Reuters system are unavailable, then the rate for
that date will be determined on the basis of the offered rates for deposits in
U.S. dollars for a period of time comparable to the applicable LIBOR Loan which
are offered by four major banks in the London interbank market at approximately
11:00 a.m. London time, on the day that is two (2) London Banking Days preceding
the first day of such LIBOR Loan as selected by the Agent. The principal London
office of each of the four major London banks will be requested to provide a
quotation of its U.S. dollar deposit offered rate. If at least two such
quotations are provided, the rate for that date will be the arithmetic mean of
the quotations. If fewer than two quotations are provided as requested, the rate
for that date will be determined on the basis of the rates quoted for loans in
U.S. dollars to leading European banks for a period of time comparable to such
LIBOR Loan offered by major banks in New York City at approximately 11:00 a.m.
New York City time, on the day that its two London Banking Days preceding the
first day of such LIBOR Loan. In the event that Agent is unable to obtain any
such quotation as provided above, it will be deemed that LIBOR pursuant to a
LIBOR Loan cannot be determined.

     In the event that the Board of Governors of the Federal Reserve System
shall impose a Reserve Requirement with respect to LIBOR deposits then for any
period during which such Reserve Requirement shall apply, LIBOR shall be equal
to the amount determined above divided by an amount equal to 1 minus the Reserve
Requirement.

     "Lien" shall mean any mortgage, pledge, hypothecation, assignment, deposit
      ----                                                                     
arrangement, encumbrance, lien (statutory or other), or preference, priority or
other security agreement of any kind or nature whatsoever (including, without
limitation, any conditional sale or other title retention agreement, any lease
that is capitalized in accordance with GAAP, and the filing of a financing
statement under the UCC or comparable law of any jurisdiction), together with
any renewal or extension thereof.

     "Liquid Investments" means (a) depositary accounts with a Lender; (b)
      ------------------                                                  
certificates of deposit issued by a Lender; (c) obligations issued or guaranteed
by the United States of America; (d) commercial paper; (e) repurchase
obligations entered into with a Lender; and (f) investments in money market or
bond funds sponsored or administered by an Affiliate of a Lender.

     "Loans" shall mean the Revolving Credit Loans.
      -----                                        

     "Loan Documents" shall mean, collectively, this Agreement, the Notes, the
      --------------                                                          
Security Instruments, the Subsidiary Guaranties, the Subsidiary Security
Agreements and all other agreements and instruments that are from time to time
executed in connection with this Agreement, as each of such agreements and
instruments may be amended, modified or supplemented from time to time.

     "Maintenance Capital Expenditures" shall mean any expenditures for fixed
      --------------------------------                                       
assets made by the Borrower or any of its Subsidiaries which are capitalized and
which are necessary to maintain the existing operations of the Borrower and its
Subsidiaries on an ongoing basis and incurred during the relevant period.

     "Majority Lenders" shall mean, at any time while no Loans are outstanding,
      ----------------                                                         
the Lenders having at least fifty-one percent (51%) of the aggregate amount of
the Commitments and, at any time while Loans are outstanding, Lenders holding at
least fifty-one percent (51%) of the outstanding aggregate principal amount of
the Loans.

     "Material Adverse Effect" shall mean a material adverse effect on (a) the
      -----------------------                                                 
business, operations, property, condition (financial or otherwise) or prospects
of the Borrower and its   
<PAGE>
 
Subsidiaries taken as a whole, (b) the ability of the Borrower to perform its
obligations under this Agreement, the Notes or any of the other Loan Documents
or (c) the validity or enforceability of this Agreement, the Notes or any of the
other Loan Documents or the ability of any Significant Subsidiary to perform its
obligations under the Subsidiary Guaranty or any of the other Loan Documents to
which it is a party, or the rights and remedies of the Agent and the Lenders
hereunder or thereunder.

     "Maturity Date" shall mean December 4, 2001.
      -------------                              

     "Maximum Rate" shall have the meaning set forth in Section 4.1(d).
      ------------                                                     

     "Multiemployer Plan" shall mean at any time an employee pension benefit
      ------------------                                                    
plan within the meaning of Section 4001(a)(3) of ERISA to which the Borrower or
any member of the Controlled Group is then making or accruing an obligation to
make contributions or has within the preceding five plan years made
contributions, including for these purposes any Person which ceased to be a
member of the Controlled Group during such five year period.

     "Net Income" or "Net Loss" for any period in respect of which the amount
      ----------      --------                                               
thereof shall be determined, shall mean the aggregate of the consolidated net
income (or net loss) after taxes for such period of the Borrower and its
Subsidiaries, determined in accordance with GAAP.

     "Net Worth" shall mean, at any date as of which the amount thereof is to be
      ---------                                                                 
determined, the stockholders' equity (including preferred stock) of the Borrower
and its Subsidiaries as determined in accordance with GAAP, provided that in
                                                            --------        
determining Net Worth any preferred stock shall be treated as equity.

     "Notes" shall have the meaning set forth in Section 2.2.
      -----                                                  

     "Notice Date" shall have the meaning set forth in Section 12.8.
      -----------                                                   

     "Obligations" shall mean all obligations of the Borrower and its
      -----------                                                    
Subsidiaries to the Agent and the Lenders of every kind and nature whether such
obligations are now existing or hereafter incurred or created, joint or several,
direct or indirect, absolute or contingent, due or to become due, matured or
unmatured, liquidated or unliquidated, arising by contract, operation of law or
otherwise, including, without limitation, (a) all principal of and interest
(including, without limitation, any interest which accrued after the
commencement of any case, proceeding or other action relating to the bankruptcy,
insolvency or reorganization of the Borrower) on any advance to the Borrower
under the Notes issued by the Borrower or pursuant to this Agreement; (b) all
other amounts (including, without limitation, any fees or expenses) payable by
Borrower or the Guarantors under the Loan Documents; (c) all amounts payable to
the Issuing Bank in connection with the issuance of any letter of credit by the
Issuing Bank for the account of any Borrower or any drawing thereunder,
including, without limitation, any reimbursement obligation and letter of credit
fees payable under any letter of credit application or reimbursement agreement
executed by the Borrower in connection with any such letter of credit; and (d)
any renewals, refinancings or extensions of any of the foregoing.

     "Office of the Agent" shall mean the Banking office of the Agent located at
      -------------------                                                       
One Federal Street, Boston, MA 02110 or such other location of which the Agent
shall notify the Borrower.

     "Payor" shall have the meaning set forth in Section 4.5.
      -----                                                  
<PAGE>
 
     "PBGC" shall mean the Pension Benefit Guaranty Corporation or any entity
      ----                                                                   
succeeding to any or all of its functions under ERISA.

     "Permitted Acquisition" shall have the meaning set forth in Section 9.2.
      ---------------------                                                  

     "Permitted Liens" shall have the meaning set forth in Section 9.6.
      ---------------                                                  

     "Person" shall mean and include any individual, firm, corporation, trust,
      ------                                                                  
limited liability company or other unincorporated organization or association or
other enterprise or any government or political subdivision, agency, department
or instrumentality thereof.

     "Plan" means any employee pension benefit plan which is covered by Title IV
      ----                                                                      
of ERISA or subject to the minimum funding standards under Section 412 of the
Code and is either (a) maintained by the Borrower or any member of the
Controlled Group for employees of the Borrower or any member of the Controlled
Group or (b) maintained pursuant to a collective bargaining agreement or any
other arrangement under which more than one employer makes contributions and to
which the Borrower or any member of the Controlled Group is then making or
accruing an obligation to make contributions or has within the preceding five
plan years made contributions.

     "Post-Default Rate" shall mean (i) with respect to any LIBOR Loan, the rate
      -----------------                                                         
of interest per annum equal to 4% above the interest rate otherwise applicable
to such LIBOR Loan at the applicable time, (ii) with respect to any Prime Rate
Loan, the rate of interest per annum equal to 4% above the interest rate
otherwise applicable to such Prime Rate Loan, and (iii) with respect to any
other amount payable by the Borrower under this Agreement which is not paid when
due, the rate of interest per annum equal to 4% above the Prime Rate at the
applicable time.

     "Prime Rate" shall mean the variable per annum rate of interest so
      ----------                                                       
designated from time to time by Fleet as its prime rate.  The Prime Rate is a
reference rate and does not necessarily represent the lowest or best rate being
charged to any customer.

     "Prime Rate Loan" means at any time the principal amount of the Loans which
      ---------------                                                           
bears interest at the Prime Rate.

     "Regulation D" means Regulation D of the Board of Governors of the Federal
      ------------                                                             
Reserve System as the same may be amended or supplemented from time to time.

     "Regulatory Change" means any change on or after the date of this Agreement
      -----------------                                                         
in United States federal, state or foreign laws or regulations, including
Regulation D, or the adoption or making on or after such date of any
interpretations, directives or requests applying to a class of lenders including
any of the Lenders of or under any United States federal or state, or any
foreign, laws or regulations (whether or not having the force of law) by any
court or governmental or monetary authority charged with the interpretation or
administration thereof (other than changes which affect taxes measured by or
imposed on the overall net income of any Lender or of its LIBOR Lending Office
by the jurisdiction in which the Lenders has its principal office or LIBOR
Lending Office).

     "Reimbursement Obligation" shall mean the  Obligation of the Borrower to
      ------------------------                                               
reimburse the Issuing Bank and the Lenders on account of any drawing under any
Letter of Credit as provided in Section 2.5.

     "Rental Payments" means rental payments in respect of operating lease
      ---------------                                                     
obligations for facilities of the Borrower and its Subsidiaries.
<PAGE>
 
     "Required Payment" shall have the meaning set forth in Section 4.5.
      ----------------                                                  

     "Reserve Requirement" shall mean, for any LIBOR Loans for any Interest
      -------------------                                                  
Period therefor, the average maximum rate at which reserves (including any
marginal, supplemental or emergency reserves) are required to be maintained
during such Interest Period under Regulation D by the Lenders against
"Eurocurrency liabilities" (as such term is used in Regulation D).

     "Responsible Officer" shall mean the President, the Chief Financial Officer
      -------------------                                                       
or the Vice President of Financial Operations.

     "Restricted Payment" shall mean, with respect to the Borrower or any
      ------------------                                                 
Subsidiary thereof, (a) any dividend or other distribution on any shares of
capital stock of the Borrower or such Subsidiary (except dividends payable
solely to the Borrower or any Subsidiary), and (b) any payment on account of the
purchase, redemption, retirement or acquisition of (i) any shares of the capital
stock of the Borrower or a Subsidiary thereof or (ii) any option, warrant,
convertible security or other right to acquire shares of the capital stock of
the Borrower or a Subsidiary thereof, other than, in either case, payments made
solely to the Borrower or such Subsidiary.

     "Revenue" for any period in respect of which the amount thereof shall be
      -------                                                                
determined, shall mean the aggregate of the consolidated revenue for such period
of the Borrower and its Subsidiaries, determined in accordance with GAAP.

     "Revolving Credit Commitment" shall have the meaning specified in Section
      ---------------------------                                             
2.1.

     "Revolving Credit Loans" shall have the meaning set forth in Section 2.1.
      ----------------------                                                  

     "SEC" means the Securities and Exchange Commission.
      ---                                               

     "Security Agreement" shall have the meaning set forth in Section 5.1.
      ------------------                                                  

     "Security Instruments" shall mean, collectively, the Security Agreement,
      --------------------                                                   
the Subsidiary Security Agreements, the Stock Pledge Agreements and each other
instrument or agreement that purports to secure the Obligations of the Borrower
to the Lenders.

     "Serrao" shall mean Gregory A. Serrao.
      ------                               

     "Significant Subsidiary" means a Guarantor which has annualized revenues of
      ----------------------                                                    
10% or more of the consolidated revenues of the Borrower and its Subsidiaries.
For purposes of this definition, annualized revenues shall be calculated based
upon the financial statements prepared for the most recent fiscal quarter of the
Person in question.

     "Stated Rate" shall have the meaning set forth in Section 4.1(d).
      -----------                                                     

     "Stock Pledge Agreements" shall have the meaning set forth in Section 5.1.
      -----------------------                                                  

     "Subordinated Debt" shall mean Indebtedness of the Borrower that is
      -----------------                                                 
subordinated to the Indebtedness of the Borrower owing to the Lenders either (a)
pursuant to a subordination agreement in the form (with conforming changes to
dates, parties and amounts and such other changes which, in the reasonable
judgment of the Agent, do not affect in any adverse manner the subordination of
such Indebtedness to the Indebtedness of the Borrower owing to the Lenders) of
the Subordination Agreement, dated June 1, 1998, entered into by the Borrower in
connection
<PAGE>
 
with the acquisition by American Dental Partners of Virginia, Inc., a subsidiary
of Borrower of substantially all of the assets of Reston Dental Group, P.C. and
previously provided to and approved by the Agent, (b) in such form and substance
as may be satisfactory to the Majority Lenders between the Borrower (or the
Agent) and the holder(s) of such Indebtedness, or (c) pursuant to the terms
thereof, where the Majority Lenders have confirmed in writing that such terms
are satisfactory to them.

     "Subsidiary" shall mean, with respect to any Person, any corporation or
      ----------                                                            
other entity of which securities or other ownership interests having ordinary
voting power to elect a majority of the board of directors or other Persons
performing similar functions are at the time directly or indirectly owned by
such Person.

     "Subsidiary Collateral" shall mean the collateral of each Subsidiary
      ---------------------                                              
described in the Subsidiary Security Agreements.

     "Subsidiary Guaranty" shall mean the amended and restated unlimited
      -------------------                                               
guaranty agreement, substantially in the form of Exhibit E hereto, entered into
                                                 ---------                     
by each Subsidiary of the Borrower (other than a shell acquisition subsidiary
with little or no assets).

     "Subsidiary Security Agreements" shall mean, collectively, security
      ------------------------------                                    
agreements, each substantially in the form of Exhibit C hereto, entered into by
                                              ---------                        
each Subsidiary of the Borrower.

     "Total Debt" shall mean the following (without duplication) with respect to
      ----------                                                                
the Borrower and its Subsidiaries: (i) all indebtedness for borrowed money
(other than trade liabilities, which shall include payables to affiliated dental
groups which are classified as current liabilities on the balance sheet of the
Borrower, incurred in the ordinary course of business and payable in accordance
with customary practices); (ii) all obligations evidenced by bonds, indentures,
notes and similar instruments; (iii) all Capital Lease Obligations; and (iv) all
liabilities secured by any Lien on any property owned by the Borrower,
regardless of whether such liabilities are non-recourse.

     "Trailing Twelve Month Revenue" shall mean for the twelve-month period
      -----------------------------                                        
ending on the last day of the most recently ended fiscal quarter of the Borrower
and its Subsidiaries the sum of (i) Revenue of the Borrower and its Subsidiaries
for such period determined in accordance with GAAP plus (ii) revenue of Persons
acquired in Permitted Acquisitions consummated during such twelve-month period,
determined in accordance with GAAP, that is not otherwise included in clause (i)
above.

     "Type" shall mean a Prime Rate Loan or a LIBOR Loan.
      ----                                               

     "UCC" shall mean the Uniform Commercial Code as in effect from time to time
      ---                                                                       
in The Commonwealth of Massachusetts.

     "Unfunded Liabilities" means, with respect to any Plan, at any time, the
      --------------------                                                   
amount (if any) by which (a) the present value of all benefits under such Plan
exceeds (b) the fair market value of all Plan assets allocable to such benefits,
all determined as of the then most recent valuation date for such Plan, but only
to the extent that such excess represents a potential liability of the Borrower
or any member of the Controlled Group to the PBGC or such Plan under Title IV of
ERISA.

     "Wholly-owned Subsidiary" shall mean, as to any Person, a Subsidiary of
      -----------------------                                               
such Person all of whose outstanding shares of capital stock are owned directly
or indirectly by such Person.
<PAGE>
 
     "Working Day" shall mean any day on which dealings in foreign currencies
      -----------                                                            
and exchange between Lenders may be carried on in the place where the LIBOR
Lending Office is located and in Boston, Massachusetts.

     Accounting Terms.  Unless otherwise specified herein, all accounting terms
     ----------------                                                          
used herein shall be interpreted, all determinations with respect to accounting
matters hereunder shall be made, and all financial statements and certificates
and reports as to financial matters required to be delivered hereunder shall be
prepared, in accordance with GAAP; provided that if any change in GAAP in itself
                                   --------                                     
materially affects the calculation of any financial covenant in this Agreement,
the Borrower may by notice to the Agent, or the Agent may by notice to the
Borrower, require that such covenant thereafter be calculated in accordance with
GAAP as in effect, and applied by the Borrower, immediately before such change
in GAAP occurs. If such notice is given, the compliance certificates delivered
pursuant to Section 8.5(c) after such change occurs shall be accompanied by
reconciliations of the difference between the calculation set forth therein and
a calculation made in accordance with GAAP as in effect from time to time after
such change occurs.

Rules of Interpretation.
----------------------- 

     A reference to any document or agreement shall include such document or
agreement as amended, modified or supplemented and in effect from time to time
in accordance with its terms and the terms of this Agreement.

     The singular includes the plural and the plural includes the singular.

     A reference to any Person includes its permitted successors and permitted
assigns.

     The words "include", "includes" and "including" are not limiting.

     The words "herein", "hereof", "hereunder" and words of like import shall
refer to this Agreement as a whole and not to any particular section or
subdivision of this Agreement.

     All terms not specifically defined herein or by GAAP, which terms are
defined in the Uniform Commercial Code as in effect in The Commonwealth of
Massachusetts, shall have the meanings assigned to them in such Code.

Revolving Credit Loans; Letters of Credit.
----------------------------------------- 

     Amount.  Upon the terms and subject to conditions set forth herein, and in
     ------                                                                    
reliance upon the representations, warranties and covenants of the Borrower
herein, the Lenders agree, severally and not jointly, to make loans (each a
"Revolving Credit Loan" and collectively the "Revolving Credit Loans") to the
 ---------------------                        ----------------------         
Borrower and the Issuing Bank hereby agrees to issue Letters of Credit for the
account of the Borrower at the Borrower's request from time to time from and
after the Closing Date and prior to the Maturity Date in an aggregate principal
amount not to exceed at any one time outstanding the sum of $50,000,000 (the
"Revolving Credit Commitment"), as the same may be reduced or terminated
 ---------------------------                                            
pursuant to the provisions hereof, provided that the sum of all outstanding
                                   --------                                
Revolving Credit Loans and Letter of Credit Usage shall not at any time exceed
the Revolving Credit Commitment.  Within the foregoing limits and subject to the
terms and conditions hereof, the Borrower may request Letters of Credit and may
borrow, repay and reborrow Revolving Credit Loans at any time or from time to
time until the Maturity Date or the earlier termination of the Revolving Credit
Commitment.
<PAGE>
 
     Revolving Credit Note.  The Revolving Credit Loans shall be evidenced by
     ---------------------                                                   
separate promissory notes for each Lender, each such note to be in substantially
the form attached hereto as Exhibit A, dated as of the Closing Date and
                            ---------                                  
completed with appropriate insertions (each such note being referred to herein
as a "Note" and collectively as the "Notes") and shall be payable with interest
      ----                           -----                                     
in accordance with Section 4 below.

     Lending Office.  The Loans of each Type made by each Lender shall be made
     --------------                                                           
and maintained at such Lender's Applicable Lending Office for Loans of such
Type.

     Requests For Revolving Credit Loans. Whenever the Borrower desires to
     -----------------------------------                                  
obtain a Revolving Credit Loan or to convert an outstanding Revolving Credit
Loan from one Type to another, it shall notify the Agent in accordance with the
provisions of Section 4.4 below.  Not later than 1:00 p.m. Boston time on the
              -----------                                                    
date specified for each such borrowing hereunder, each Lender shall, subject to
the terms and conditions of this Agreement, make available the amount of the
Revolving Credit Loan to be made by it on such date to the Agent at the Office
of the Agent, for the account of the Borrower.  Subject to the terms and
conditions of this Agreement, the amount so received by the Agent shall be made
available to the Borrower by wiring the funds to such account as the Borrower
shall specify.

Letters of Credit.
----------------- 

     The Borrower may use the Revolving Credit Commitment for Letters of Credit
to be issued by the Issuing Bank, provided that in each case (a) the Borrower
                                  --------                                   
executes and delivers a letter of credit application and reimbursement agreement
reasonably satisfactory to the Issuing Bank and complies with any conditions to
the issuance of such Letter of Credit (including payment of any applicable
fees); (b) the Issuing Bank has approved the form of such Letter of Credit; (c)
the requested Letter of Credit is for a purpose permitted by Section 8.1 hereof;
(d) such Letter of Credit bears an expiration date not later than one year from
its date of issuance and not later than the Maturity Date; (e) the conditions
set forth in Section 6.1 shall have been satisfied as of the date of the
issuance of the Letter of Credit; and (f) both before the issuance of the
requested Letter of Credit and after giving effect to the issuance thereof the
sum of (i) all outstanding Revolving Credit Loans and Letter of Credit Usage
shall not exceed the Revolving Credit Commitment; and (ii) the Letter of Credit
Usage shall not exceed $3,000,000.

     Effective upon the issuance of each Letter of Credit and without any
further action on the part of the Issuing Bank or the Lenders in respect
thereof, the Issuing Bank hereby grants to each Lender, and each Lender hereby
acquires from the Issuing Bank, a participating interest in such Letter of
Credit to the extent of such Lender's Commitment Percentage thereof and each
Lender severally agrees that it shall be absolutely liable, without regard to
the occurrence of any Default or Event of Default, to the extent of such
Lender's Commitment Percentage thereof, to reimburse the Issuing Bank on demand
for the amount of each draft paid by the Issuing Bank under each Letter of
Credit to the extent that such amount is not reimbursed by the Borrower.  Each
Lender's obligation to make further Loans to the Borrower shall be reduced by
such Lender's Percentage of Letter of Credit Usage.

     In order to induce the Issuing Bank to issue, extend and renew each Letter
of Credit, the Borrower hereby agrees to reimburse or pay to the Issuing Bank,
for the account of the Issuing Bank or (as the case may be) the Lenders, with
respect to each Letter of Credit issued, extended or renewed by the Issuing Bank
hereunder, on each date that any draft presented under any Letter of Credit is
honored by the Issuing Bank or the Issuing Bank otherwise makes payment with
respect thereto, (i) the amount paid by the Issuing Bank under or with respect
to such Letter of 
<PAGE>
 
Credit, and (ii) the amount of any reasonable and customary fees, charges or
other costs and expenses whatsoever incurred by the Issuing Bank or any Lender
in connection with any payment made by the Issuing Bank under, or with respect
to, such Letter of Credit.

     If any draft shall be presented or other demand for payment shall be made
under any Letter of Credit, the Issuing Bank shall notify the Borrower of the
date and amount of the draft presented or demand for payment and of the date and
time when it expects to pay such draft or honor such demand for payment. On the
date that such draft is paid or other payment is made by the Issuing Bank, the
Issuing Bank shall promptly notify the Lenders of the amount of any unpaid
Reimbursement Obligation.  All such unpaid Reimbursement Obligations with
respect to Letters of Credit shall be deemed to be Prime Rate Loans.  No later
than 12:00 noon (Boston time) on the Banking Day next following the receipt of
such notice, each Lender shall make available to the Agent, at the Agent's head
office, in immediately available funds, such Lender's Commitment Percentage of
such unpaid Reimbursement Obligation, together with an amount equal to the
product of (i) the average,  computed for the period referred to in clause (iii)
below, of the weighted average interest rate paid by the Agent for federal funds
acquired by the Agent during each day included in such period, times (ii) the
                                                               -----         
amount equal to such Lender's Commitment Percentage of such unpaid Reimbursement
Obligation, times (iii) a fraction, the numerator of which is the number of days
            -----                                                               
that have elapsed from and including the date the Issuing Bank paid the draft
presented for honor or otherwise made payment until the date on which such
Lender's Commitment Percentage of such unpaid Reimbursement Obligation shall
become immediately available to the Agent, and the denominator of which is 365.
The responsibility of the Issuing Bank to the Borrower shall be only to
determine that the documents (including each draft) delivered under each Letter
of Credit in connection with such presentment shall be in conformity in all
material respects with such Letter of Credit.

     The Borrower's Reimbursement Obligations shall be absolute and
unconditional under any and all circumstances and irrespective of the occurrence
of any Default or Event of Default or any condition precedent whatsoever or any
set off, counterclaim or defense to payment which the Borrower may have or have
had against the Issuing Bank, the Agent, the Lenders or any beneficiary of a
Letter of Credit. The Borrower further agrees that the Issuing Bank, the Agent
and the Lenders shall not be responsible for, and the Borrower's Reimbursement
Obligations shall not be affected by, among other things, the validity or
genuineness of documents or of any endorsements thereon, even if such documents
should in fact prove to be in any or all respects invalid, fraudulent or forged,
or any dispute between or among the Borrower, the beneficiary of any Letter of
Credit or any financing institution or other party to which any Letter of Credit
may be transferred or any claims or defenses whatsoever of the Borrower, against
the beneficiary of any Letter of Credit or any such transferee.

     The Issuing Bank, the Agent and the Lenders shall not be liable for any
error, omission, interruption or delay in transmission, dispatch or delivery of
any message or advice, however transmitted, in connection with any Letter of
Credit.  The Borrower agrees that any action taken or omitted by the Issuing
Bank, the Agent or the Lenders under or in connection with each Letter of Credit
and the related drafts and documents, if done in good faith, shall be binding
upon the Borrower and shall not result in any liability on the part of the
Issuing Bank, the Agent or the Lenders to the Borrower except, in the case of
any such party, any such liability resulted from the gross negligence or willful
misconduct of such party.

     Maturity of Revolving Credit Loans.  All Revolving Credit Loans shall
     ----------------------------------                                   
mature and the total unpaid principal amount thereunder shall be due and payable
on the Maturity Date, or such earlier date on which the Revolving Credit Loans
and all other sums owing under this Agreement 
<PAGE>
 
and the other Loan Documents shall be due as a result of acceleration, at which
time all amounts advanced under this Section 2 shall be immediately due and
payable.

Termination or Reduction of Commitment.
-------------------------------------- 

     The Revolving Credit Commitment shall automatically terminate at 5:00 p.m.
Boston time on the Maturity Date. The Borrower, upon notice to the Agent and
each Lender in accordance with Section 4.4 and the repayment in full of the
outstanding principal balance of the Revolving Credit Loans (and accrued
interest thereon) and the payment in full of any expenses or other fees owed by
the Borrower to the Agent or any Lender under or pursuant to this Agreement, may
elect to terminate the Revolving Credit Commitment permanently, whereupon the
Commitments of the Lenders shall be terminated entirely. If any Letters of
Credit would remain outstanding after the effective date of any such
termination, in addition to the satisfaction of all other applicable terms and
conditions of this Agreement, the Borrower shall either deposit with and pledge
to the Agent cash in an amount equal to 100% of the Letter of Credit Usage at
the effective date of such termination, or (ii) arrange for the termination of
such Letters of Credit and the return thereof to the Issuing Bank. No such
termination may be reinstated.

     The Borrower may also, upon notice to the Agent and each Lender in
accordance with Section 4.4, reduce the Revolving Credit Commitment in integral
multiples of $500,000, whereupon the Commitments of the Lenders shall be reduced
pro rata in accordance with their respective Commitment Percentages by the
aggregate amount specified in such notice. If, as a result of any such
reduction, the aggregate outstanding balance of Revolving Credit Loans plus the
Letter of Credit Usage would exceed the Revolving Credit Commitment, the
Borrower shall, as a condition precedent to any such reduction, deposit with and
pledge to the Agent cash in an amount equal to 100% of such excess or to make
repayments of outstanding Revolving Credit Loans in an aggregate amount equal to
such excess. No such reduction may be reinstated.

     Several Obligations.  The failure of any Lender to make any Loan to be made
     -------------------                                                        
by it on the date specified therefor shall not relieve any other Lender of its
obligation to make its Loan on such date, but neither the Agent nor any Lender
shall be responsible for the failure of any other Lender to make a Loan to be
made by such other Lender.

[Intentionally Omitted]

Interest Rates; Fees; Payments.
------------------------------ 

Interest Rates.
-------------- 

     The Borrower agrees to pay to the Agent for the account of each Lender
interest on the unpaid principal amount of each Loan for each day from and
including the date such Loan is made to but excluding the date the principal of
such Loan is paid in full at the following rates per annum:

          1.1.1.1. for Loans which are Prime Rate Loans, at a rate per annum
                   equal to the Prime Rate plus the Applicable Margin; and

          1.1.1.2. for Loans which are LIBOR Loans, at a rate per annum equal to
                   the LIBOR Rate plus the Applicable Margin.

                   Notwithstanding the foregoing, if an Event of Default shall
                   occur, then at the option of the Agent or the Majority
                   Lenders, the unpaid balance of
<PAGE>
 
               Loans and any other amount payable hereunder which is not paid in
               full when due shall bear interest at a rate per annum equal to
               the Post-Default Rate, until such Event of Default is cured or
               waived.

               Accrued interest on each Prime Rate Loan shall be payable monthly
               in arrears on the first day of each month, accrued interest on
               LIBOR Loans shall be payable on the last day of each Interest
               Period and, if any such Interest Period is longer than three
               months, at intervals of three months after the first day thereof,
               and interest on all Loans shall be payable in any event upon the
               payment, prepayment or conversion thereof, but only on the
               principal so paid or prepaid or converted; provided that interest
                                                          --------              
               payable pursuant to Section 4.1(b) during the pendency of an
               Event of Default shall be payable from time to time on demand of
               the Agent.  Promptly after the determination of any interest rate
               provided for herein or any change therein, the Agent shall notify
               the Borrower and each of the Lenders thereof.

               Notwithstanding the foregoing provisions of this Section 4.1, if
               at any time the rate of interest set forth in subparagraph (a)
               above (the "Stated Rate") exceeds the maximum non-usurious
                           -----------                                   
               interest rate permissible for any Lender to charge a commercial
               borrower under applicable law (the "Maximum Rate"), the rate of
                                                   ------------               
               interest charged on the Loans by such Lender hereunder shall be
               limited to the Maximum Rate. In the event the Stated Rate that
               has theretofore been subject to the preceding sentence at any
               time is less than the Maximum Rate in respect of the Loans
               hereunder by any Lender, the principal amount of the Loans shall
               bear interest at the Maximum Rate until the total amount of
               interest paid to such Lender or accrued on such Loans by such
               Lender hereunder equals the amount of interest which would have
               been paid to the Lenders or accrued on the Loans by the Lenders
               hereunder if the Stated Rate had at all times been in effect. In
               the event that upon payment in full of all amounts payable
               hereunder, the total amount of interest paid to any Lender or
               accrued on such Lender's Loans under the terms of this Agreement
               is less than the total amount of interest which would have been
               paid to such Lender or accrued on such Lender's Loans if the
               Stated Rate had at all times been in effect, then the Borrower
               shall, to the extent permitted by applicable law, pay to such
               Lender an amount equal to the difference between (a) the lesser
               of (i) the amount of interest which would have accrued on the
               Loans if the Maximum Rate had at all times been in effect or (ii)
               the amount of interest which would have accrued on the Loans if
               the Stated Rate had at all times been in effect and (b) the
               amount of interest actually paid to the Lenders or accrued on the
               Loans under this Agreement. In the event any Lender ever
               receives, collects or applies as interest any sum in excess of
               the Maximum Rate, such excess amount shall be applied to the
               reduction of the principal balance of such Lender's Loans or to
               other amounts (other than interest) payable hereunder, and if no
               such principal is then outstanding, such excess or part thereof
               remaining shall be paid to the Borrower.

               Commitment Fee.  The Borrower shall pay to the Agent for the
               --------------                                              
               ratable account of each Lender quarterly in arrears on the first
               day of each quarter a commitment fee on the actual daily balance
               of the unutilized portion of 
<PAGE>
 
               the Commitment for the preceding quarter at a rate per annum as
               set forth on Schedule 1 attached hereto based on the actual
               number of days elapsed in the period based on a year of 360 days.

               Letter of Credit Fees.  In connection with each Letter of Credit,
               ---------------------                                            
               the Borrower shall pay to the Issuing Bank any applicable
               issuance, amendment, transfer and similar fees in accordance with
               the Issuing Bank's customary charges and in connection with the
               issuance or extension of any Standby Letter of Credit shall also
               pay an annual standby commission equal to the then effective
               Applicable Margin for LIBOR Loans minus 0.125% of the total face
               amount of such Standby Letter of Credit.

               Certain Notices.  Notices to the Agent of borrowings, conversions
               ---------------                                                  
               and prepayments of Loans, of the duration of Interest Periods and
               of termination or reduction of Commitments shall be irrevocable
               and shall be effective only if received by the Lenders not later
               than the time specified below on the number of Banking Days prior
               to the date of the borrowing, conversion, prepayment, termination
               or reduction specified below:

                                                Number of Banking  Time of Day
                                                Days Prior Notice (Boston Time)
                                                ----------------- -------------
               Borrowings or prepayment           
               of Prime Rate Loans                    0            11:00 a.m.
                                                   
               Borrowings of, prepayment          
               of, conversion into, or            
               duration of Interest Periods       
               for LIBOR Loans                        2            10:30 a.m.
                                                   
               Termination or reduction           
               of Commitments                         3            12:00 noon
 

               Each notice of borrowing, conversion or prepayment shall specify
               the amount, the Type of the Loan to be borrowed, converted or
               prepaid, the date of borrowing, conversion or prepayment (which
               shall be a Banking Day in the case of the prepayment of a Prime
               Rate Loan, or a Working Day in the case of the conversion or
               prepayment of a LIBOR Loan) and, in the case of LIBOR Loans, the
               duration of the Interest Period therefor (subject to the
               definition of Interest Period). Each such notice of duration of
               an Interest Period shall specify the Loans to which such Interest
               Period is to relate, provided, however, as long as an Event of
               Default has occurred and is continuing, the Borrower's right to
               request new LIBOR Loans shall cease. In the event that the
               Borrower fails to select the duration of any Interest Period for
               any LIBOR Loan within the time period and otherwise as provided
               in this Section 4.4, such LIBOR Loan will be automatically
               converted into a Prime Rate Loan on the last day of the then
               current Interest Period for such LIBOR Loan or (if outstanding as
               Prime Rate Loans) will remain as, or (if not then outstanding)
               will be made as Prime Rate Loans.
<PAGE>
 
               Non-Receipt of Funds by the Agent.  Unless the Agent shall have
               ---------------------------------                              
               been notified by a Lender or the Borrower (the "Payor") prior to
                                                               -----           
               the date on which such Lender is to make payment to the Agent of
               the proceeds of a Loan to be made by it hereunder or the Borrower
               is to make a payment to the Agent for the account of one or more
               of the Lenders, as the case may be (such payment being herein
               called the "Required Payment"), which notice shall be effective
                           ----------------                                   
               upon receipt, that the Payor does not intend to make the Required
               Payment to the Agent, the Agent may assume that the Required
               Payment has been made and may, in reliance upon such assumption
               (but shall not be required to), make the amount thereof available
               to the intended recipient on such date and, if the Payor has not
               in fact made the Required Payment to the Agent, the recipient of
               such payment shall, on demand, pay to the Agent the amount made
               available to it together with interest thereon in respect of the
               period commencing on the date such amount was so made available
               by the Agent until the date the Agent recovers such amount at a
               rate per annum equal to the Federal Funds Rate for such period.

               Sharing of Payment; Waiver of Enforcement Without Consent, Etc.
               -------------------------------------------------------------- 

               The Borrower agrees that, in addition to (and without limitation
               of) any right of set-off, banker's lien or counterclaim any
               Lender may otherwise have, each Lender shall be entitled, at its
               option and without regard to the adequacy of any other Collateral
               or Subsidiary Collateral held by or for the benefit of such
               Lender, to offset balances (whether based on provisional or final
               credits or on collected or uncollected funds), credits,
               securities or other property of the Borrower or any Subsidiary
               held by such Lender, for the account of the Borrower at any of
               its offices, in Dollars or in any other currency (collectively,
               the "Deposited Funds"), against any principal of or interest on
                    ---------------                                           
               any Loans to the Borrower by any Lender hereunder, or any other
               Obligation of the Borrower hereunder, which is not paid when due,
               taking into account any applicable grace period, (regardless of
               whether such balances are then due to the Borrower), in which
               case it shall promptly notify the Borrower, the Agent and the
               other Lenders thereof, provided that such Lender's failure to
               give such notice shall not affect the validity thereof.  The
               Borrower further grants to the Agent for the benefit of the Agent
               and each Lender a lien, security interest and right of set-off in
               all such Deposited Funds, it being agreed that the possession of
               any such Deposited Funds by any Lender shall be for the benefit
               of the Agent and the Lenders, provided, however, that nothing
                                             --------  -------              
               herein shall restrict the Borrower from using such Deposited
               Funds unless and until a Default or Event of Default shall have
               occurred and be continuing.  The Borrower agrees, to the fullest
               extent it may effectively do so under applicable law, that any
               Person purchasing a participation in the Loans made, or other
               obligations held, by another Person, whether or not acquired
               pursuant to the foregoing arrangements, may exercise all rights
               of set-off, banker's lien, counterclaim or similar rights with
               respect to such participation as fully as if such Lender were a
               direct holder of Loans or other obligations in the amount of such
               participation.  ANY AND ALL RIGHTS TO REQUIRE THE AGENT OR A
               LENDER TO EXERCISE ITS RIGHTS OR REMEDIES WITH RESPECT TO ANY
               OTHER COLLATERAL WHICH SECURES THE 
<PAGE>
 
               LOAN, PRIOR TO EXERCISING ITS RIGHT OF SETOFF WITH RESPECT TO
               SUCH DEPOSITS, CREDITS OR OTHER PROPERTY OF THE BORROWER OR ANY
               GUARANTOR, ARE HEREBY KNOWINGLY, VOLUNTARILY AND IRREVOCABLY
               WAIVED.

               The Lenders agree among themselves that no Lender shall, except
               with the written consent of the Majority Lenders, exercise any
               right pursuant to Section 4.6(a) or exercise, with respect to any
                                 --------------                                 
               Loans or other obligations hereunder, any other right of set-off,
               banker's Lien, counterclaim or similar right, so long as any
               Lender has any Commitment hereunder or any amounts due hereunder
               remain unpaid.

               If a Lender shall obtain payment of any principal of or interest
               on any Loan made by it under this Agreement, or on any other
               obligation then due to such Lender hereunder, through the
               exercise of any right of set-off, banker's lien, counterclaim or
               similar right, or otherwise, it shall promptly notify the Agent
               and purchase from the other Lenders participations in the Loans
               made, or other obligations held, by the other Lenders in such
               amounts, and make such other adjustments from time to time as
               shall be equitable to the end that all the Lenders shall share
               the benefit of such payment (net of any expenses which may be
               incurred by such Lender in obtaining or preserving such benefit)
               pro rata in accordance with the unpaid principal and interest on
               the Loans or other obligations then due to each of them. To such
               end, all the Lenders shall make appropriate adjustments among
               themselves (by the resale of participations sold or otherwise) if
               such payment is rescinded or must otherwise be restored
               (including the payment of interest to the extent that the Lender
               obligated to return such funds is obligated to return interest).

               Each Lender waives all rights to enforce, and shall not attempt
               to enforce, any rights hereunder, under the Notes or under any
               other Loan Document without the prior written consent of the
               Majority Lenders.  Each Lender further agrees that all rights
               under the Security Instruments shall be exercised only through
               the Agent under the Security Instruments.

               Nothing contained herein shall require any Lender to exercise any
               right of set-off, banker's Lien, counterclaim or similar right or
               shall affect the right of any Lender to exercise, and retain the
               benefits of exercising, any such right with respect to any other
               indebtedness or obligation of any Borrower.

               This Section 4.6 is for the benefit of the Lenders only and does
                    -----------                                                
               not constitute a waiver of any rights against the Borrower or any
               of its Subsidiaries or against any property held as security for
               any obligations hereunder or under any Loan Document.

               Minimum and Maximum Amounts.  Each borrowing, conversion and
               ---------------------------                                 
               prepayment of principal of Revolving Credit Loans shall be in an
               aggregate principal amount equal to (a) in the case of LIBOR
               Loans, $500,000 or a larger multiple of $100,000, and (b) in the
               case of Prime Rate Loans, $250,000 or a larger multiple of
               $50,000 (conversions or prepayments of Revolving Credit Loans of
               different Types or, in the case of LIBOR Loans, having different
               Interest Periods, at the same time 
<PAGE>
 
               hereunder shall be deemed separate conversions and prepayments
               for purposes of the foregoing, one for each Type or Interest
               Period); provided that any payment or prepayment in full of the
                        --------
               Loans may be in the aggregate outstanding principal amount
               thereof.

               Computations. All interest on LIBOR Loans shall be computed on
               ------------                                                   
               the basis of a year of 360 days and actual days elapsed
               (including the first day but excluding the last day) occurring in
               the period for which payable and all interest on Prime Rate Loans
               shall be computed on the basis of a year of 365 days (or 366 days
               in the case of a leap year) and actual days elapsed (including
               the first but excluding the last day) occurring in the period for
               which payable.

               Manner and Place of Payment.  All payments under this Agreement
               ---------------------------                                    
               shall be made not later than 1:00 p.m. (Boston Time) on the date
               when due and shall be made in lawful money of the United States
               in immediately available funds at the Office of the Agent for the
               account of each Lender or by the Borrower's check drawn on the
               depositary account(s) maintained by the Borrower with the Agent
               payable to the Agent for the account of each Lender or its order.
               All payments shall be made without setoff, counterclaim,
               withholding or reduction of any kind whatsoever.  The Agent (or
               any Lenders for whose account any such payment is made) may (but
               shall not be obligated to) debit the amount of any such payment
               on the date when due, taking into account any applicable grace
               period, to any ordinary deposit account of the Borrower with the
               Agent, or such Lender, as the case may be, without notice to the
               Borrower.  The Borrower shall, at the time of making each payment
               hereunder or under any Note, specify to the Agent the Loans or
               other amounts payable by the Borrower hereunder to which such
               payment is to be applied (and in the event that they fail to so
               specify, or if an Event of Default has occurred and is
               continuing, the Agent may apply such payment for the benefit of
               the Lenders as it may elect in its sole discretion, but subject
               to the other terms and conditions of this Agreement, including
               without limitation, Section 4.10 hereof).  Each payment received
                                   ------------                                
               by the Agent hereunder or under any Note for the account of a
               Lender shall be paid promptly to such Lender, in immediately
               available funds, for the account of such Lender's Applicable
               Lending Office.

               Pro Rata Treatment.  Except to the extent otherwise provided
               -------------------                                         
               herein:  (a) each borrowing from the Lenders under Section 2.1
                                                                  -----------
               hereof shall be made from the Lenders and the payment of the
               commitment fee under Section 4.2 hereof shall be made for the
                                    -----------                             
               account of the Lenders pro rata according to the Lenders'
               Commitment Percentage, (b) each payment by the Borrower of
               principal of or interest on Loans of a particular Type shall be
               made to the Agent for the account of the Lenders pro rata in
               accordance with the respective unpaid principal amounts of such
               Loans held by the Lenders and (c) each conversion of Loans of a
               particular Type shall be made pro rata among the Lenders in
               accordance with the respective principal amounts of such Loans
               held by the Lenders.

               Payments Due on Days Other than Banking Days.  Subject to the
               --------------------------------------------                 
               definition of "Interest Period" with respect to LIBOR Loans as
               set forth in 
<PAGE>
 
               Section 1.1, whenever any payment to be made hereunder or under
               the Notes shall be due on a day which is not a Banking Day, such
               payment may be made on the next succeeding Banking Day, and such
               extension of time shall be included in computing any interest or
               fees due.

               Additional Costs.
               ---------------- 

               The Borrower shall pay to the Agent for the account of each
               Lender from time to time such amounts as such Lender may
               determine to be necessary to compensate it for any costs incurred
               by such Lender which such Lender determines are attributable to
               its making or maintaining of any LIBOR Loans hereunder or its
               obligation to make any of such Loans hereunder, or any reduction
               in any amount receivable by such Lender hereunder in respect of
               any LIBOR Loan or such obligation (such increases in costs and
               reductions in amounts receivable being herein called "Additional
                                                                     ----------
               Costs"), in each case resulting from any Regulatory Change which:
               -----                                                            

     1.1.1.3.  changes the basis of taxation of any amounts payable to such
               Lender under this Agreement or the Notes in respect of any LIBOR
               Loan; or

     1.1.1.4.  imposes or modifies any reserve, special deposit or similar
               requirements (other than the Reserve Requirement, to the extent
               it is taken into consideration in determining the LIBOR Rate)
               relating to any extensions of credit or other assets of, or any
               deposits with or other liabilities of, such Lender (including any
               LIBOR Loan or any deposits referred to in the definition of
               "LIBOR Rate" below).

               Each Lender will provide the Borrower notice of any event
               occurring after the date of this Agreement which will entitle
               such Lender to compensation pursuant to this Section as promptly
               as practicable after it obtains knowledge thereof and determines
               to request such compensation. Each Lender will furnish the
               Borrower with a statement, in reasonable detail, setting forth
               the basis and amount of each request by such Lender for
               compensation under this Section. Within 30 days of the notice by
               such Lender, the Borrower shall pay the Agent for the benefit of
               the affected Lender that portion of such increased costs incurred
               or reduction in an amount received which is attributable to
               making, funding and maintaining such affected Lender's Loans
               hereunder. If such sum is not paid within such 30 day period, it
               shall bear interest at the Post-Default Rate until paid in full.
               The Borrower shall not be required to make any such payment for
               such increased costs arising prior to the date which is one
               hundred twenty (120) days before the date of such notice (unless
               and only to the extent such law, rule, regulation, policy,
               guideline, directive or interpretation applies retroactively to a
               period prior to the date which is one hundred twenty (120) days
               before the date of such notice, in which case, the Borrower shall
               not be required to make any payment for increased costs resulting
               from such retroactive application unless such Lender provides
               such notice within one hundred twenty (120) days after such rule,
               regulation, policy, guideline, directive or interpretation is
               published in final form and the Lender reasonably should have
               been aware thereof. If any affected Lender shall subsequently
               recoup costs for which such Lender has heretofore been
               compensated by the Borrower under this
<PAGE>
 
               Section 4.12, such Lender shall remit to the Borrower the amount
               of such recoupment.

               Without limiting the effect of the foregoing provisions of this
               Section, in the event that, by reason of any Regulatory Change,
               any Lender either (i) incurs Additional Costs based on or
               measured by the excess above a specified level of the amount of a
               category of deposits or other liabilities of such Lender which
               includes deposits by reference to which the interest rate on
               LIBOR Loans is determined as provided in this Agreement or a
               category of extensions of credit or other assets of such Lender
               which includes LIBOR Loans or (ii) becomes subject to
               restrictions on the amount of such a category of liabilities or
               assets which it may hold, then, if such Lender so elects by
               notice to the Borrower, the obligation of such Lender to make
               LIBOR Loans hereunder shall be suspended until the date such
               Regulatory Change ceases to be in effect.

     1.1.1.5.  Determinations and allocations by any Lender for purposes of this
               Section of the effect of any Regulatory Change on its costs of
               maintaining its obligations to make LIBOR Loans or of making or
               maintaining LIBOR Loans or on amounts receivable by it in respect
               of LIBOR Loans, and of the additional amounts required to
               compensate such Lender in respect of any Additional Costs, shall
               be conclusive absent manifest error, provided that such
               determinations and allocations are made on a reasonable basis.

               Limitation on Types of Loans.  Anything herein to the contrary
               ----------------------------                                  
               notwithstanding, if, with respect to any LIBOR Loans, the
               Majority Lenders determine in good faith (which determination
               shall be conclusive) that the relevant rates of interest referred
               to in the definition of "LIBOR Rate" upon the basis of which the
               rates of interest for any LIBOR Loan are to be determined do not
               accurately reflect the cost to such Lenders of making or
               maintaining such LIBOR Loans for the Interest Period therefor,
               then the Agent shall promptly notify the Borrower, and so long as
               such condition remains in effect, the Lenders shall be under no
               obligation to make LIBOR Loans or to convert Prime Rate Loans
               into LIBOR Loans and the Borrower shall, on the last day(s) of
               the then current Interest Period(s) for the outstanding LIBOR
               Loans, either prepay such LIBOR Loans or convert such LIBOR Loans
               into Prime Rate Loans.

               Illegality.  Notwithstanding any other provision of this
               ----------                                              
               Agreement to the contrary, in the event that it becomes unlawful
               for any Lender or its LIBOR Lending Office to (a) honor its
               obligation to make LIBOR Loans hereunder, or (b) maintain LIBOR
               Loans hereunder, then such Lender shall promptly notify the
               Borrower thereof (identifying the illegality in question in
               reasonable detail) and such Lenders's obligation to make LIBOR
               Loans hereunder shall be suspended until such time as such Lender
               may again make and maintain LIBOR Loans.

               Substitute Prime Rate Loans.  If the obligation of any Lender to
               ---------------------------                                     
               make LIBOR Loans shall be suspended pursuant to Sections 4.12,
               4.13 or 4.14 hereof, all Loans which would otherwise be made by
               such Lender as LIBOR Loans shall be made instead as Prime Rate
               Loans (and, if an event referred to in Section 4.12(b) or Section
               4.14 has occurred and such 
<PAGE>
 
               Lender so requests, by notice to the Borrower, each LIBOR Loan of
               such Lender then outstanding shall be automatically converted
               into a Prime Rate Loan on the date specified by such Lender in
               such notice) and, to the extent that LIBOR Loans are so made as
               (or converted into) Prime Rate Loans, all payments of principal
               which would otherwise be applied to such LIBOR Loans shall be
               applied instead to such Prime Rate Loans.

               Compensation.  If any payment, prepayment or conversion of a
               ------------                                                
               LIBOR Loan occurs on a date other than the last day of an
               Interest Period for such Loan, the Borrower shall pay to the
               Agent for the account of each Lender, upon the request of the
               Lender through the Agent, as compensation for any loss, cost or
               expense incurred by such Lender as the result of such payment,
               prepayment or conversion, an amount (if a positive number) equal
               to:


                              A  x  (B-C)  X    D
                             --------------------
                                      360

                                    where:

     "A" equals the principal amount of the LIBOR Loan so paid, prepaid or
     converted (the "Affected LIBOR Loan");
                     -------------------   

     "B" equals the LIBOR Rate (expressed as a decimal) applicable to the
     Affected LIBOR Loan;

     "C" equals the applicable LIBOR Rate (expressed as a decimal) in effect on
     or about the date of such payment, prepayment or conversion, for deposits
     in an amount equal approximately to the principal amount of the Affected
     LIBOR Loan with an Interest Period (the "Remaining Interest Period")
                                              -------------------------  
     beginning on the date of such payment, prepayment or conversion to but
     excluding the last day of the existing Interest Period; and

     "D" equals the number of days in the Remaining Interest Period;

               and any other out-of-pocket loss or expense (including any
               internal processing charge customarily charged by such Lender)
               suffered by such Lender in liquidating deposits prior to maturity
               in amounts which correspond to the principal amount of the
               Affected LIBOR Loan; provided that such Lender shall have
                                    --------                            
               delivered to the Borrower a certificate, in reasonable detail, as
               to the amount of such loss and expense along with the basis for
               calculation thereof. Determination of amounts payable to a Lender
               in connection with a LIBOR Loan shall be calculated as though a
               Lender funded its LIBOR Loan through the purchase of a deposit of
               the type and maturity corresponding to the deposit used as a
               reference in determining the LIBOR Rate applicable to such Loan,
               whether in fact that is the case or not.

               Capital Adequacy.  If any Lender shall determine that the
               ----------------                                         
               applicability of any law, rule, regulation or guideline adopted
               pursuant to or arising out of the July 1988 report of the Basle
               Committee on Banking Regulations and Supervisory Practices
               entitled "International Convergence of Capital 
<PAGE>
 
               Measurement and Capital Standards", or the adoption after the
               date hereof of any other applicable law, rule, regulation or
               guideline regarding capital adequacy, or any change in the
               foregoing or in the enforcement, interpretation or administration
               thereof by any Governmental Authority charged with the
               enforcement, interpretation or administration thereof, or
               compliance by such Lender or any Person controlling such Lender
               (a "Parent") with any request or directive regarding capital
                   ------
               adequacy (whether or not having the force of law) of any such
               Governmental Authority, has or would have the effect of reducing
               the rate of return on capital of such Lender or its Parent as a
               consequence of such Lender's obligations hereunder to a level
               below that which such Lender (or its Parent) could have achieved
               but for such applicability, adoption, change or compliance
               (taking into consideration the policies of such Lender (or its
               Parent) with respect to capital adequacy) by an amount reasonably
               deemed by such Lender to be material, then such Lender shall
               provide the Borrower notice thereof. A statement of such Lender,
               in reasonable detail, claiming compensation under this Section
               and setting forth the additional amount or amounts to be paid to
               it hereunder shall be conclusive absent manifest error; provided
                                                                       --------
               that the determination thereof is made on a reasonable basis. In
               determining such amount, such Lender may use any reasonable
               averaging and attribution methods. Within 30 days of the
               notification by such Lender, the Borrower shall pay the Agent for
               the benefit of the affected Lender that portion of such increased
               costs incurred (including any reduction in the rate of return on
               capital to an amount below that which such Lender could have
               achieved but for such change in regulation after taking into
               account the Lenders' policies as to capital adequacy) or
               reduction in an amount received which is attributable to making,
               funding and maintaining such affected Lender's Loans hereunder.
               If such sum is not paid within such 30 day period, it shall bear
               interest at the Post-Default Rate until paid in full. The
               Borrower shall not be required to make any such payment for such
               increased costs arising prior to the date which is one hundred
               twenty (120) days before the date of such notice (unless and only
               to the extent such law, rule, regulation, policy, guideline,
               directive or interpretation applies retroactively to a period
               prior to the date which is one hundred twenty (120) days before
               the date of such notice, in which case, the Borrower shall not be
               required to make any payment for increased costs resulting from
               such retroactive application unless such Lender provides such
               notice within one hundred twenty (120) days after such rule,
               regulation, policy, guideline, directive or interpretation is
               published in final form and the Lender reasonably should have
               been aware thereof). If any affected Lender shall subsequently
               recoup costs for which such Lender has heretofore been
               compensated under this Section 4.17 by the Borrower, such Lender
               shall remit to the Borrower the amount of such recoupment.

               Optional Prepayments.  The Borrower shall have the right to
               --------------------                                       
               prepay the Loans in whole or in part and to convert Loans of one
               Type into another Type, without premium or penalty, at any time
               and from time to time, provided that (i) at the time of the
                                      --------                            
               prepayment in full of all Extensions of Credit, the Borrower
               shall pay all interest accrued on the amount prepaid; (ii) the
               Borrower shall give the Agent notice of such prepayment as
               provided in Section 4.4; (iii) LIBOR Loans may be converted into
               Prime 
<PAGE>
 
               Rate Loans only on the last day of an Interest Period thereof;
               and (iv) the Agent for the account of each Lender shall be paid,
               at the time of any prepayment of a LIBOR Loan that is being
               prepaid on other than the last day of an Interest Period
               therefor, the amount provided for in Section 4.16.

               Mandatory Prepayments.  In the event the Borrower closes any
               ---------------------                                       
               public offering of its capital stock after the date hereof, the
               Borrower shall be required to prepay the Loans in an amount equal
               to the net proceeds (after costs and expenses associated with
               such offering) received by the Borrower in such offering.

               Security.
               -------- 

               Security Interests.
               ------------------ 

               The Borrower agrees to grant to the Agent for the benefit of the
               Lenders on the Closing Date a security interest in, and a lien
               on, all right, title and interest of the Borrower in and to
               substantially all the assets of the Borrower (excluding Excluded
               Property) and to enter into a security agreement in favor of the
               Agent for the benefit of the Lenders in the form of Exhibit B
                                                                   ---------
               hereto (the "Security Agreement") in order to secure payment and
                            ------------------                                 
               performance of the Borrower's Obligations to the Agent and the
               Lenders under this Agreement, the Notes and the other Loan
               Documents to which it is a party.

               The Borrower shall cause each of its Subsidiaries to grant to the
               Agent for the benefit of the Lenders on the Closing Date a
               security interest in, and a lien on, all right, title and
               interest of each such Subsidiary in and to substantially all the
               assets of each such Subsidiary and to enter into a security
               agreement in favor of the Agent for the benefit of the Lenders in
               substantially the form of Exhibit C hereto (collectively, the
                                         ---------                          
               "Subsidiary Security Agreements") in order to secure payment and
                ------------------------------                                 
               performance of the Borrower's Obligations to the Agent and the
               Lenders under this Agreement, the Notes and the other Loan
               Documents.

               The Borrower agrees to enter into stock pledge agreements in
               favor of the Agent for the benefit of the Lenders in the form of
               Exhibit D attached hereto (the "Stock Pledge Agreements")
               ---------                       -----------------------  
               providing for the pledge to the Agent for the benefit of the
               Lenders of all outstanding capital stock of all present and
               future Subsidiaries of the Borrower and to deliver to the Agent
               for the benefit of the Lenders certificates representing all such
               shares accompanied by undated stock powers or other appropriate
               instruments of transfer duly executed in blank.

               Conditions Precedent.
               -------------------- 

               Conditions to all Loans and Letters of Credit.  The Lenders shall
               ---------------------------------------------                    
               not be obligated to make any of the Loans to the Borrower and the
               Issuing Bank shall not be obligated to issue any Letter of Credit
               hereunder until the following conditions have been satisfied to
               the satisfaction of the Agent:
<PAGE>
 
               This Agreement the Notes and the Security Instruments.  This
               -----------------------------------------------------       
               Agreement, the borrowings hereunder, the Notes, the Security
               Instruments and all transactions contemplated by this Agreement
               and the Security Instruments shall have been duly authorized by
               the Borrower.  The Subsidiary Guaranty and Security Instrument to
               which a Guarantor is a party and all transactions contemplated
               thereby shall have been duly authorized by such Guarantor.  The
               Borrower shall have duly executed and delivered to the Agent this
               Agreement, the Notes and the Security Instruments in form and
               substance satisfactory to the Agent and its counsel.  Each of the
               Guarantors shall have duly executed and delivered to the Agent a
               Subsidiary Guaranty substantially in the form of Exhibit E hereto
                                                                ---------       
               and a Subsidiary Security Agreement substantially in the form of
               Exhibit C hereto.
               ---------        

               No Default or Event of Default.  On the date hereof and on the
               ------------------------------                                
               date of making each Extension of Credit, no Default or Event of
               Default shall have occurred and be continuing.

               Correctness of Representations.  On the Closing Date and on the
               ------------------------------                                 
               date of each Extension of Credit, all representations and
               warranties made by the Borrower in Section 7 below or otherwise
               in writing in connection herewith shall be true and correct with
               the same effect as though such representations and warranties had
               been made on and as of today's date, except that representations
               and warranties expressly limited to a certain date shall be true
               and correct as of that date.

               Opinion of Counsel for the Borrower.  The Agent shall have
               -----------------------------------                       
               received the favorable opinion of counsel to the Borrower and the
               Guarantors addressed to the Agent and the Lenders, in form and
               substance reasonably satisfactory to the Agent and its counsel.

               Approvals.  On the Closing Date and on the date of each Extension
               ---------                                                        
               of Credit, all necessary consents, approvals, licenses,
               permissions, registrations or validations of any Governmental
               Authority or any other Person required for the execution,
               delivery, performance or carrying out of the provisions of this
               Agreement, the Notes, the Subsidiary Guaranties and the Security
               Instruments, or for the validity or enforceability of the
               obligations incurred thereunder (other than the filing of
               financing statements as required under subparagraph (f) below),
               shall have been obtained and shall be in full force and effect
               and copies thereof certified by a duly authorized officer of the
               Borrower to such effect shall have been delivered to the Agent.

               Filing of Financing Statements, etc.  On or before the Closing
               -----------------------------------                           
               Date, financing statements or other appropriate documentation
               relating to the security interests and rights granted pursuant to
               the Security Instruments, executed and delivered by the Borrower
               to the Agent, shall have been duly recorded or filed in such
               manner and in such places as is required by law (including,
               pursuant to the UCC) to establish, preserve, protect, and perfect
               such security interests and rights; and all taxes, fees and other
               charges in connection with the execution, delivery and filing of
               this 
<PAGE>
 
               Agreement and such financing statements and other appropriate
               documentation shall have been duly paid.

               Supporting Documents.  On or before the date hereof, there shall
               --------------------                                            
               have been delivered to the Agent the following supporting
               documents:

     1.1.1.6.  a long-form legal existence and corporate good standing
               certificates with respect to the Borrower and each of the
               Guarantors dated as of a recent date issued by the appropriate
               Secretary of State or other official;

     1.1.1.7.  certificates dated as of a recent date with respect to the due
               qualification of the Borrower and each of the Guarantors to do
               business in each jurisdiction where the failure to be so
               qualified would have a Material Adverse Effect, issued by the
               Secretary of State of each such jurisdiction;

     1.1.1.8.  copies of the corporate charters of the Borrower and each of the
               Guarantors, certified by the appropriate Secretary of State or
               other officials, as in effect on the date hereof;

     1.1.1.9.  a certificate of the Secretary or Assistant Secretary of the
               Borrower certifying as to (a) the By-Laws of the Borrower, as in
               effect on the date hereof; (b) the incumbency and signatures of
               the officers of the Borrower who have executed any documents in
               connection with the transactions contemplated by this Agreement;
               and (c) the resolutions of the Board of Directors of the Borrower
               authorizing the execution, delivery and performance of this
               Agreement and the making of the Loans hereunder, and the
               execution and delivery of the Notes and the other Loan Documents;

     1.1.1.10. a certificate of the Secretary or Assistant Secretary of
               each Guarantor certifying as to (a) the By-Laws of the such
               Guarantor, as in effect on the date hereof; (b) the incumbency
               and signatures of the officers of such Guarantor who have
               executed any documents in connection with the transactions
               contemplated by this Agreement; and (c) the resolutions of the
               Boards of Directors of such Guarantor authorizing the execution,
               delivery and performance of the Subsidiary Guaranty and
               Subsidiary Security Agreement to which it is a party.

     1.1.1.11. all other information and documents which the Agent or its
               counsel may reasonably request in connection with the
               transactions contemplated by this Agreement.

               Compliance Certificate.  The Borrower shall have furnished to the
               ----------------------                                           
               Agent a Compliance Certificate in the form of attached Exhibit F
                                                                      ---------
               appropriately completed and signed by a Responsible Officer of
               the Borrower, which certificate shall reflect compliance by the
               Borrower with the requirements of this Agreement as of the date
               thereof.

               Litigation.  No litigation, arbitration, proceeding or
               ----------                                            
               investigation shall be pending or, to the knowledge of the
               Borrower, threatened against any 
<PAGE>
 
               Borrower or any Subsidiary of a Borrower which, in the sole
               judgement of the Agent, might have a Material Adverse Effect.

               Fees and Expenses.  On or before the Closing Date, the Borrower
               -----------------                                              
               shall have (i) paid to the Agent for the account of the Lenders
               all amounts payable under Section 13.5 hereof identified by the
                                         ------------                         
               Agent on or before the Closing Date; and (ii) paid to the Agent
               all fees due under a certain letter between the Agent and the
               Borrower, dated the date hereof.

               Legal Matters.  All documents and legal matters incident to the
               -------------                                                  
               transactions contemplated by this Agreement shall be reasonably
               satisfactory to Sullivan & Worcester LLP, special counsel for the
               Agent.

                        Representations and Warranties.
                        ------------------------------ 

               In order to induce the Agent and the Lenders to enter into this
               Agreement and to make the contemplated Extensions of Credit, the
               Borrower hereby represents and warrants as follows to the Agent
               and the Lenders  (except to the extent qualified by supplemental
               disclosure set forth on Schedule A hereto) and the following
                                       ----------                          
               representations and warranties (to the extent so qualified, if
               any) shall survive the execution and delivery of this Agreement
               and the Notes:

               Corporate Status.  The Borrower and each Guarantor is a duly
               ----------------                                            
               organized and validly existing corporation in good standing under
               the laws of the state of its organization and is duly qualified
               or licensed as a foreign corporation in good standing in each
               jurisdiction in which the failure to do so would have a Material
               Adverse Effect.

               No Violation.  Neither the execution, delivery or performance of
               ------------                                                    
               this Agreement or any other Loan Document, nor consummation of
               the transactions contemplated therein or thereby will (i)
               contravene any law, statute, rule or regulation to which the
               Borrower or any Guarantor is subject or any judgment, decree,
               franchise, order or permit applicable to the Borrower or any
               Guarantor where such contravention has or could reasonably be
               anticipated to have a Material Adverse Effect, or (ii) conflict
               or be inconsistent with or will result in any breach of, or
               constitute a default under, or result in or require the creation
               or imposition of any Lien (other than the liens created by the
               Security Instruments) upon any of the property or assets of the
               Borrower or any Guarantor pursuant to, any Contractual Obligation
               of the Borrower or any Guarantor, or (iii) violate any provision
               of the corporate charters or by-laws of the Borrower or any
               Guarantor.

               Corporate Power and Authority.  The execution, delivery and
               -----------------------------                              
               performance of this Agreement and the other Loan Documents to
               which it is a party are within the corporate powers of the
               Borrower and each Guarantor and have been duly authorized by all
               necessary corporate action.

               Enforceability.  This Agreement and each other Loan Document to
               --------------                                                 
               which it is a party constitutes valid and binding obligations of
               the Borrower and each Guarantor enforceable against the Borrower
               and each Guarantor in 
<PAGE>
 
               accordance with its terms, except as be limited by applicable
               bankruptcy, insolvency, reorganization, moratorium or other laws
               affecting the enforcement of creditors' rights generally and
               subject to general principles of equity, whether applied in a
               court of equity or at law.

               Consents or Approvals.  No order, permission, consent, approval,
               ---------------------                                           
               license, authorization, registration or validation of, or filing
               with, or exemption by, any Governmental Authority or any other
               Person is required to authorize, or is required in connection
               with, the execution, delivery and performance of this Agreement
               or any other Loan Document by the Borrower or any Guarantor, or
               the taking of any action contemplated hereby or thereby, except
               where the failure to obtain such authorization could reasonably
               be anticipated to have a Material Adverse Effect and except for
               the filing of UCC-1 financing statements in the appropriate UCC
               filing offices listed on the Perfection Certificate (as defined
               in the Security Agreement) and for routine filings under federal
               securities laws.

                             Financial Statements.
                             -------------------- 

               The Borrower has furnished the Agent with the consolidated
               balance sheet of the Borrower and its Subsidiaries as of the
               Financial Statement Date, and the related consolidated statements
               of operations, stockholders' equity and cash flows for the year
               then ended, which have been audited by the Accountants.  Such
               financial statements, including the related schedules and notes,
               fairly present the consolidated financial position of the
               Borrower and its Subsidiaries as of the Financial Statement Date,
               and the results of their operations and their cash flows for the
               year then ended in conformity with GAAP.

               During the period from the Financial Statement Date to the
               Closing Date:  (i) except as permitted pursuant to Section 9.3 or
               identified in Schedule A or in the Borrower's Form 10-Qs filed
               with the SEC for the first three quarters of 1998 or the
               Borrower's Form S-4 Registration Statement dated November 18,
               1998 as filed with the SEC, copies of which have previously been
               delivered to Agent, there has been no sale, transfer or other
               disposition by the Borrower or any of its Subsidiaries of any
               material part of their business or property and, except as set
               forth in Schedule A, no purchase or other acquisition of any
                        ----------                                         
               business or property (including any capital stock of any Person)
               material in relation to the consolidated financial condition of
               the Borrower and its Subsidiaries at the Financial Statement
               Date; and (ii) neither the Borrower nor any of its Subsidiaries
               have made a Restricted Payment, or agreed or committed to make a
               Restricted Payment, except as permitted pursuant to Section 9.7.

               The Borrower has and, after giving effect to the Loans to be made
               on the Closing Date, will have, assets (both tangible and
               intangible),  having a value in excess of the amount required to
               pay the probable liability on its then-existing debts (whether
               matured or unmatured, liquidated or unliquidated, fixed or
               contingent); the Borrower has and will have access to adequate
               capital for the conduct of its business and the discharge of its
               debts incurred in connection therewith as such debts mature; the
               Borrower was not insolvent immediately prior to the making of the
               Loans on the 
<PAGE>
 
               Closing Date and immediately after giving effect thereto, the
               Borrower will not be insolvent.

               All the above-referenced financial statements (including the
               related schedules and notes) have been prepared in accordance
               with GAAP applied consistently throughout the periods involved
               (except as approved by the Accountants and disclosed therein and,
               in the case of interim financial statements, subject to normal
               year-end adjustments and the absence of footnotes and schedules).

               No Material Change.  Since the Financial Statement Date there has
               ------------------                                               
               been no development or event, or to the best knowledge of the
               Borrower, any prospective development or event, which has had or
               could reasonably be anticipated to have a Material Adverse
               Effect.

               Litigation. There are no actions, suits or proceedings pending or
               ----------                                                       
               threatened against or affecting the Borrower or any of its
               Subsidiaries which in any one case or in the aggregate, if
               determined adversely to the interests of such party, could
               reasonably be anticipated to have a Material Adverse Effect.

               Compliance with Other Instruments; Compliance with Law.  Neither
               ------------------------------------------------------          
               the Borrower nor any of its Subsidiaries are (after taking into
               account applicable cure periods) in default under any Contractual
               Obligation (including any Contractual Obligation relating to any
               Indebtedness of the Borrower) where such default could reasonably
               be anticipated to have a Material Adverse Effect.  Neither the
               Borrower nor any of its Subsidiaries are in default and/or in
               violation of any applicable statute, rule, writ, injunction,
               decree, order or regulation of any Governmental Authority having
               jurisdiction over the Borrower or its Subsidiaries which default
               or violation could reasonably be anticipated to have a Material
               Adverse Effect.

               Subsidiaries.  On the Closing Date, the Borrower does not have
               ------------                                                  
               any Subsidiaries except as set forth on attached Schedule A.
                                                                ---------- 

               Investment Company Status; Limits on Ability to Incur
               -----------------------------------------------------
               Indebtedness.  The Borrower is not an "investment company" or a
               ------------                                                   
               company "controlled by" an investment company within the meaning
               of the Investment Company Act of 1940, as amended.  The Borrower
               is not subject to regulation under any Federal or State statute
               or regulation which limits its ability to incur Indebtedness.

               Title to Property.  The Borrower and each of its Subsidiaries has
               -----------------                                                
               good and marketable title to all of its properties and assets,
               including the properties and assets reflected in the consolidated
               balance sheet of the Borrower as of the Financial Statement Date,
               except such as have been disposed of since that date in the
               ordinary course of business, and none of such properties or
               assets is subject to any Lien except for (a) Permitted Liens, or
               (b) a defect in title or other claim other than defects and
               claims that, in the aggregate, would have no Material Adverse
               Effect.  The Borrower and each of its Subsidiaries enjoys
               peaceful and undisturbed possession under all leases 
<PAGE>
 
               necessary in any material respect for the operation of their
               properties and assets and no material default exists under such
               leases (after taking into account applicable cure periods under
               said leases). All such leases are valid and subsisting and are in
               full force and effect.

               ERISA.  The Borrower and each member of the Funding Standard
               -----                                                       
               Controlled Group have fulfilled their obligations under the
               minimum funding standards of ERISA and the Code with respect to
               pension plans maintained by the Borrower or any member of the
               Funding Standard Controlled Group or to which the Borrower or any
               member of the Funding Standard Controlled Group is obligated to
               contribute, except where the failure to fulfill such obligations
               would not result in the aggregate of an "accumulated funding
               deficiency", within the meaning of Section 302 of ERISA, in
               excess of $250,000.  The Borrower and each member of the
               Controlled Group are in compliance in all material respects with
               the presently applicable provisions of ERISA and the Code, and
               have not incurred any liability to the PBGC or a Plan under Title
               IV of ERISA (other than to make contributions or premium payments
               in the ordinary course).

               Taxes.  All tax returns of the Borrower and its Subsidiaries
               -----                                                       
               required to be filed have been timely filed (after giving effect
               to any permitted extensions) except for any tax returns which if
               not filed on a timely basis would not have a Material Adverse
               Effect, all material taxes, fees and other governmental charges
               (other than those being  contested in good faith by appropriate
               proceedings diligently conducted and with respect to which
               adequate accruals have been established and, in the case of ad
                                                                           --
               valorem taxes or betterment assessments, no proceedings to
               -------                                                   
               foreclose any lien with respect thereto have been commenced and,
               in all other cases, no notice of lien has been filed or other
               action taken to perfect or enforce such lien) shown thereon which
               are payable have been paid.  The charges and reserves on the
               books of the Borrower and its Subsidiaries for all income and
               other taxes are adequate, and the Borrower knows of no additional
               assessment or any basis therefor.  The Federal income tax returns
               of the Borrower and its Subsidiaries have not been audited within
               the last three years, all prior audits have been closed, and
               there are no unpaid assessments, penalties or other charges
               arising from such prior audits.

                            Environmental Matters.
                            --------------------- 

               The Borrower and each of its Subsidiaries have obtained all
               Governmental Approvals that are required for the operation of
               their business under any Environmental Law, except where the
               failure to so obtain a Governmental Approval would not have a
               Material Adverse Effect.

               The Borrower and each of its Subsidiaries are in compliance with
               all terms and conditions of all required Governmental Approvals
               and are also in compliance with all terms and conditions of all
               applicable Environmental Laws, noncompliance with which would
               have a Material Adverse Effect.
<PAGE>
 
               There is no civil, criminal or administrative action, suit,
               demand, claim, hearing, notice of violation, investigation,
               proceeding, notice or demand letter pending or, to the best
               knowledge of the Borrower threatened against the Borrower or any
               of its Subsidiaries relating in any way to the Environmental Laws
               which could have a Material Adverse Effect, and there is no Lien
               of any private entity or Governmental Authority against any
               Borrower Group Property, which Lien could have a Material Adverse
               Effect.

               There has been no claim, complaint, notice, or request for
               information received by the Borrower or any Subsidiary with
               respect to any site listed on the National Priority List
               promulgated pursuant to the Comprehensive Environmental Response,
               Compensation, and Liability Act ("CERCLA") 42 USC (S) 9601 et
                                                 ------                   --
               seq. or any state list of sites requiring investigation or
               ----                                                      
               cleanup with respect to contamination by Hazardous Substances,
               which claim, complaint, notice, or request for information could
               have a Material Adverse Effect.

               To the best of the Borrower's knowledge, there has been no
               release or threat of release of any Hazardous Substance at any
               Borrower Group Property which would likely result in liability
               being imposed upon the Borrower or any Subsidiary thereof, which
               liability would have a Material Adverse Effect.

               Intellectual Property.  The Borrower and each of its Subsidiaries
               ---------------------                                            
               owns or licenses such copyrights, patents, trademarks and similar
               rights ("Intellectual Property") as are necessary for the conduct
                        ---------------------                                   
               of its respective businesses as now conducted, without any known
               conflict with the rights of others which would have a Material
               Adverse Effect.

               Level of Borrowing.  After giving effect to any Extensions of
               ------------------                                           
               Credit to be made as of the date hereof under this Agreement, the
               sum of all outstanding Revolving Credit Loans and Letter of
               Credit Usage do not exceed the Revolving Credit Commitment.

               Malpractice Insurance.  The senior management of the Borrower,
               ---------------------                                         
               and each of its Subsidiaries, has concluded, after the exercise
               of reasonable business judgment, that such entities are not
               engaged in the practice of dentistry and are not required to
               maintain malpractice insurance and that if such senior management
               concludes after the Closing Date that such entities are required
               to maintain malpractice insurance, the Borrower covenants and
               agrees to, and will require each of its Subsidiaries to, obtain
               and maintain comprehensive malpractice insurance against bodily
               injury and death with financially sound and reputable insurance
               companies in such amounts and against such risks as are usually
               carried by owners of similar businesses and properties in the
               same general areas in which the Borrower and its Subsidiaries
               operate..

               Year 2000 Risk.  The Borrower and each Guarantor has reviewed the
               --------------                                                   
               "Year 2000 Risk" (that is the risk that computer applications
               used by Borrower and each Guarantor and/or that suppliers,
               vendors and customers may be unable to recognize and perform
               without error date-sensitive 
<PAGE>
 
               functions involving certain dates prior to and any date after
               December 31, 1999) and the Borrower and each Guarantor is
               exercising commercially reasonable efforts to ensure that the
               Year 2000 Risk will not adversely affect their business
               operations and/or financial condition.

               Disclosure.  None of the representations or warranties made by
               ----------                                                    
               the Borrower in this Agreement, or in any other document
               furnished to the Agent or the Lenders by or on behalf of the
               Borrower in connection herewith contains (or will contain on the
               Closing Date) any untrue statement of a material fact or omits
               (or will omit on the Closing Date) to state any material fact
               necessary to make the statements herein or therein, in light of
               the circumstances under which they are made, not misleading.
               There is no fact known to the Borrower on the date of this
               Agreement which has any reasonable likelihood of having a
               Material Adverse Effect which has not been set forth in or
               referred to in this Agreement.

                            Affirmative Covenants.
                            --------------------- 

               The Borrower covenants and agrees that for so long as this
               Agreement is in effect and until the Notes, together with all
               interest thereon and all other Obligations of the Borrower and
               the Guarantors to the Lenders are paid or satisfied in full,
               unless the Majority Lenders shall otherwise consent in writing:

               Use of Proceeds.  The Borrower shall use the proceeds of
               ---------------                                         
               Revolving Credit Loans for the working capital purposes of the
               Borrower and its Subsidiaries and for Permitted Acquisitions,
               including for payments under Letters of Credit and for the costs
               and expenses of the transactions contemplated hereby. Without
               limiting the foregoing, no part of such proceeds will be used for
               the purpose of purchasing or carrying any "margin security" as
               such term is defined in Regulation U of the Board of Governors of
               the Federal Reserve System.

               Conduct of Business; Maintenance of Existence.  The Borrower
               ---------------------------------------------               
               will, and will cause of each of its Subsidiaries to, continue to
               engage in the business in which they are engaged and maintain its
               existence and comply with all applicable statutes, rules and
               regulations and remain duly qualified as a foreign corporation,
               licensed and in good standing in each jurisdiction where such
               qualification or licensing is required by the nature of its
               business, the character and location of its property, business,
               or the ownership or leasing of its property, except where such
               noncompliance or failure to so qualify would not have a Material
               Adverse Effect, and the Borrower will maintain its properties in
               good operating condition, and continue to conduct its business as
               presently conducted.

               Compliance with Laws.  The Borrower will, and will cause each of
               --------------------                                            
               its Subsidiaries to, comply in all material respects with all
               applicable laws, ordinances, rules, regulations and requirements
               of Governmental Authorities.


                                  Insurance.
                                  --------- 
<PAGE>
 
               The Borrower will, and will cause each of its Subsidiaries to,
               maintain insurance with financially sound and reputable insurance
               companies in such amounts and with such deductibles and against
               such risks as is usually carried by owners of similar businesses
               and properties in the same general areas in which the Borrower
               and its Subsidiaries operate, provided that in any event the
               Borrower and its Subsidiaries shall maintain or cause to be
               maintained (i) insurance against casualty, loss or damage
               covering all property and improvements of the Borrower and its
               Subsidiaries in amounts and in respect of perils usually carried
               by owners of similar businesses and properties in the same
               general areas in which Borrower and its Subsidiaries operate;
               (ii) comprehensive general liability insurance against claims for
               bodily injury, death or property damage; and (iii) workers'
               compensation insurance to the extent required by applicable law.
               Such policies may be blanket policies covering the Borrower and
               all its Subsidiaries. In the case of policies referenced in
               clauses (i) and (ii) above, all such insurance shall (x) name the
               Borrower and the Agent, for the benefit of the Lenders, as loss
               payees for losses exceeding $500,000 and additional insureds as
               their interests may appear; (y) provide that no termination,
               cancellation or material reduction in the amount or material
               modification to the extent of coverage shall be effective until
               at least 30 days after receipt by the Agent of notice thereof;
               and (z) be reasonably satisfactory in all other respects to the
               Agent. Notwithstanding the foregoing, the Borrower may upon a
               determination to such effect by its Board of Directors and notice
               to the Agent, self insure, in whole or in part, for risks and
               claims of the type described in clauses (i) and (ii) of the first
               sentence of this Section 8.4 to the extent that self insurance is
               normal and customary for similarly situated businesses.

               The Borrower will not enter into any management service agreement
               or similar agreement with an affiliated dentist or professional
               corporation unless such dentist or professional corporation
               agrees to maintain comprehensive malpractice insurance against
               claims for bodily injury and death with financially sound and
               reputable insurance companies in such amounts and against such
               risks as is usually carried by dentists in the same general areas
               in which such dentists operate.

               As long as no Default or Event of Default shall have occurred and
               be continuing, the Agent shall return to the Borrower any
               insurance proceeds it receives in payment of a claim filed by the
               Borrower or any of its Subsidiaries.

               Financial Statements, Etc.  The Borrower will furnish to each of
               -------------------------                                       
               the Lenders:

               within forty-five (45) days after the end of each quarter of the
               Borrower (other than the fourth quarter), the unaudited
               consolidated balance sheet as of the end of such period and the
               related consolidated statements of operations and cash flows of
               the Borrower and its Subsidiaries as of and for the three-month
               period and the year-to-date period ended on the last day of such
               quarter, accompanied by a certificate of a Responsible Officer of
               the Borrower to the effect that such financial statements fairly
               present 
<PAGE>
 
               the consolidated financial condition of the Borrower and its
               Subsidiaries as of the end of such quarter, and the consolidated
               results of their operations for such quarter, in each case in
               accordance with GAAP (except for the absence of footnotes)
               consistently applied (subject to normal year-end audit
               adjustments);

               within forty-five (45) days after the end of the second financial
               quarter of the Borrower, the unaudited consolidating balance
               sheet (which may be grouped by geographic region) as of the end
               of such period and the related unaudited consolidating statement
               of operations (which may be grouped by geographic region) for the
               six-month period ended on the last day of such quarter,
               accompanied by a certificate of a Responsible Officer of the
               Borrower to the effect that such financial statements fairly
               present the consolidated financial condition of the Borrower and
               its Subsidiaries as of the end of such period, and the
               consolidated results of their operations for such period, in each
               case in accordance with GAAP (except for the absence of
               footnotes) consistently applied (subject to normal year-end audit
               adjustments);

               within one hundred twenty (120) days after the last day of each
               year of the Borrower, the audited consolidated balance sheet and
               income statement and statement of cash flows of the Borrower and
               its Subsidiaries as of and for the year then ended, audited by
               the Accountants without any material qualifications together with
               the unaudited consolidating balance sheet and statement of
               operations of the Borrower and its Subsidiaries as of and for the
               year then ended, together with a certificate (which may be
               included as part of a Compliance Certificate) of a Responsible
               Officer of the Borrower to the effect that such financial
               statements fairly present the consolidated financial condition of
               the Borrower and its Subsidiaries as of the end of such year and
               the consolidated results of their operations for such year, in
               each case in accordance with GAAP.

               at the time of the delivery of the quarterly, six-month and
               yearly financial statements required by Sections 8.5(a), (b) and
               (c) above, a Compliance Certificate signed by a Responsible
               Officer of the Borrower in the form attached to this Agreement as
               Exhibit F, appropriately completed;
               ---------                          

               copies of any management letter provided by the Accountants and
               addressed to the Board of Directors of the Borrower or to the
               Audit Committee of the Board of Directors of the Borrower;

               promptly upon becoming aware of any litigation or other
               proceeding against the Borrower or any of its Subsidiaries that
               could reasonably be expected to have a Material Adverse Effect,
               notice thereof;

               promptly following the request of the Majority Lenders, such
               further information concerning the business, affairs and
               financial condition or operations of the Borrower and its
               Subsidiaries as the Agent may reasonably request;
<PAGE>
 
               promptly upon the mailing thereof to the shareholders of the
               Borrower generally, copies of all financial statements, reports,
               proxy statements and other materials; and

               promptly upon the filing thereof by the Borrower with the SEC
               (and in any event within ten (10) days of such filing), copies of
               any registration statements (on SEC Form S-1, S-3 or any other
               form) and reports on Forms 10-K, 10-Q and 8-K (or their
               equivalents if such forms no longer exist).

               Notice of Default.  As soon as practicable, and in any event,
               -----------------                                            
               within three (3) Banking Days of becoming aware of the existence
               of any condition or event which constitutes a Default, the
               Borrower will provide the Agent and each Lender with written
               notice specifying the nature and period of existence thereof and
               what action the Borrower is taking or proposes to take with
               respect thereto.

                            Environmental Matters.
                            --------------------- 

               The Borrower and each of its Subsidiaries shall comply with all
               terms and conditions of all applicable Governmental Approvals and
               all applicable Environmental Laws, except where failure to comply
               would not have a Material Adverse Effect.

               The Borrower shall promptly notify the Agent (and the Agent shall
               promptly thereafter notify the Lenders) should the Borrower
               become aware of:

     1.1.1.12. any spill, release, or threat of release of any Hazardous
               Substance at or from any Borrower Group Property or by any Person
               for whose conduct the Borrower or any Subsidiary thereof are
               responsible, to the extent the Borrower is required by
               Environmental Laws to report such to any Governmental Authority;

     1.1.1.13. any action or notice with respect to a civil, criminal or
               administrative action, suit, demand, claim, hearing, notice of
               violation, investigation, proceeding, notice or demand letter
               pending or threatened against the Borrower or any Subsidiary
               thereof relating in any way to the Environmental Laws, or any
               Lien of any Governmental Authority or any other Person against
               any Borrower Group Property relating in any way to the
               Environmental Laws;

     1.1.1.14. any claim made or threatened by any Person against the
               Borrower or any of its Subsidiaries or any property of the
               Borrower or any of its Subsidiaries thereof relating to damage,
               contribution, cost recovery compensation, loss or injury
               resulting from any Hazardous Substance pertaining to such
               property or the business or operations of the Borrower or such
               Subsidiary; and

     1.1.1.15. any occurrence or condition on any real property adjoining
               any Borrower Group Property known to the officers or supervisory
               personnel of the Borrower or any of its Subsidiaries or other
               employees having
<PAGE>
 
               responsibility for the compliance by the Borrower or any
               Subsidiary thereof with Environmental Laws, without any
               independent investigation, which does cause, or could cause, such
               Borrower Group Property, or any part thereof, to contain
               Hazardous Substances in violation of any Environmental Laws, or
               which does cause, or could cause, such Borrower Group Property to
               be subject to any restrictions on the ownership, occupancy,
               transferability or use thereof by the Borrower or any of its
               Subsidiaries.

               The Borrower will, and will cause each of its Subsidiaries to, at
               their own cost and expense, and within such period as may be
               required by applicable law or regulation, initiate all remedial
               actions and thereafter diligently prosecute such action as shall
               be required by law for the cleanup of such Borrower Group
               Property, including all removal, containment and remedial actions
               in accordance with all applicable Environmental Laws (and in all
               events in a manner reasonably satisfactory to the Majority
               Lenders) and shall further pay or cause to be paid, at no expense
               to the Agent or the Lenders, all cleanup, administrative, and
               enforcement costs of applicable Government Authorities which may
               be asserted against such Borrower Group Property.

               Taxes and Other Liens.  The Borrower will, and will cause each of
               ---------------------                                            
               its Subsidiaries to, pay when due all taxes, assessments,
               governmental charges or levies, or claims for labor, supplies,
               rent and other obligations made against it which, if unpaid,
               might become a Lien against the Borrower or such Subsidiary or on
               its property, except liabilities being contested in good faith
               and by proper proceedings, as to which adequate accruals are
               maintained on the books of the Borrower or its Subsidiaries, in
               accordance with GAAP.

               ERISA Information.  If and when the Borrower or any member of the
               -----------------                                                
               Controlled Group (a) gives or is required to give notice to the
               PBGC of any "reportable event" (as defined in Section 4043 of
               ERISA) with respect to any Plan which might constitute grounds
               for a termination of such Plan under Title IV of ERISA, or knows
               that the plan administrator of any Plan has given or is required
               to give notice of any such reportable event, (b) receives notice
               of complete or partial withdrawal liability under Title IV of
               ERISA or (c) receives notice from the PBGC under Title IV of
               ERISA of an intent to terminate or appoint a trustee to
               administer the Plan, the Borrower shall in each such instance
               promptly furnish to the Lenders a copy of any such notice.

               Inspection.  The Borrower will permit a representative of the
               ----------                                                   
               Agent (including any field examiner or auditor retained by the
               Agent) to inspect and make copies of the Borrower's books and
               records, and to discuss their affairs, finances and accounts with
               their officers and accountants, at such reasonable times and
               places and as often as the Agent may reasonably request.

                 Certain Obligations Respecting Subsidiaries.
                 ------------------------------------------- 
<PAGE>
 
               The Borrower will, and will cause each of its Subsidiaries to,
               take such action from time to time as shall be necessary to
               ensure that the Borrower at all times owns (subject only to the
               Lien of the Security Instruments) all of the issued and
               outstanding shares of each class of stock of each of its
               Subsidiaries. Without limiting the generality of the foregoing,
               the Borrower shall not, and shall not permit any of its
               Subsidiaries to, sell, transfer or otherwise dispose of any
               shares of stock in any Subsidiary owned by it, or permit any of
               its Subsidiaries to issue any shares of stock of any class
               whatsoever to any Person other than the Borrower. In the event
               that any such additional shares of stock shall be issued by any
               Subsidiary of the Borrower, the Borrower agrees forthwith to
               deliver to the Agent pursuant to the Security Instruments the
               certificates evidencing such shares of stock, accompanied by
               undated stock powers executed in blank and shall take such other
               action as the Agent shall request to perfect the security
               interest created therein pursuant to the Security Instruments.

               Promptly (but in any event within thirty (30) days) following the
               creation of any Subsidiary (other than a shell acquisition
               subsidiary with little or no assets) of the Borrower following
               the Closing Date, or the acquisition of any Person by a Borrower
               or any Subsidiary thereof pursuant to which such Person becomes a
               direct or indirect Subsidiary of the Borrower, the Borrower (i)
               shall notify the Agent in writing of the creation or acquisition
               of such Subsidiary (and the Agent shall promptly thereafter
               notify the Lenders) and (ii) shall cause such Subsidiary to
               become a guarantor of the performance of the Obligations and to
               execute and deliver a Subsidiary Guaranty and a Subsidiary
               Security Agreement and such other documents, in form and
               substance satisfactory to the Agent, as the Agent shall
               reasonably require in order to confirm the authorization and
               enforceability of such guaranty.

               Promptly (but in any event within thirty (30) days) following the
               creation of any Subsidiary (other than a shell acquisition
               subsidiary with little or no assets) of the Borrower following
               the Closing Date, or the acquisition of any Person by a Borrower
               or any Subsidiary thereof pursuant to which such Person becomes a
               direct or indirect Subsidiary of the Borrower, the Borrower shall
               (i) cause such Subsidiary to grant to the Agent for the benefit
               of the Lenders a security interest in, and a lien on, all right,
               title and interest of such Subsidiary in and to substantially all
               the assets of such Subsidiary (except for Excluded Property) and
               to enter into a Subsidiary Security Agreement in favor of the
               Agent for the benefit of the Lenders and such other documents, in
               form and substance satisfactory to the Agent, as the Agent shall
               reasonably require in order to confirm and perfect the
               authorization and enforceability of such security interest, and
               (ii) forthwith deliver to the Lenders pursuant to the Security
               Instruments the certificates evidencing all of the issued and
               outstanding shares of stock of such Subsidiary, accompanied by
               undated stock powers executed in blank and take such other action
               as the Agent shall request to perfect the security interest
               created therein pursuant to the Security Instruments. The
               Borrower shall, and shall cause the appropriate Subsidiaries of
               the Borrower to, promptly (x) execute and deliver to the Agent
               such number of copies as the Agent may specify of documents
               creating such Liens, (y) do all other things which may be
               necessary or which the Agent may
<PAGE>
 
               reasonably request in order to confer upon and confirm to the
               Agent the benefits of such security, and (z) deliver such
               certificates, evidences of corporate action or other documents as
               the Agent may reasonably request, all in form and substance
               reasonably satisfactory to the Lenders, relating to the
               satisfaction of the Borrower's obligations under this Section.

               Further Assurances.  The Borrower will, and will cause each of
               ------------------                                            
               its Subsidiaries to, execute and deliver to the Agent or any
               Lender any writings and do all things necessary, effectual or
               reasonably requested by the Agent to carry into effect the
               provisions and intent of this Agreement or any other Loan
               Document.

                              Negative Covenants.
                              ------------------ 

               The Borrower covenants and agrees that for so long as this
               Agreement is in effect and until the Notes, together with all
               interest thereon and all other Obligations of the Borrower and
               the Guarantors to the Lenders are paid or satisfied in full,
               without the prior written consent of the Majority Lenders:

               Transactions with Affiliates.  Except as permitted by Section 9.8
               ----------------------------                                     
               hereof or as set forth on Schedule A, the Borrower will not, and
                                         ----------                            
               will not permit any of its Subsidiaries to, directly or
               indirectly, pay any funds to or for the account of, make any
               Investment in, lease, sell, transfer or otherwise dispose of any
               assets, tangible or intangible, or engage in any transaction in
               connection with any joint enterprise or other joint arrangement
               with, any Affiliate of the Borrower, unless such transaction is
               not prohibited by this Agreement, is for reasonable business or
               tax purposes, is in the ordinary course of the Borrower's or such
               Subsidiary's business, and is upon fair and reasonable terms no
               less favorable to the Borrower or such Subsidiary as those that
               could be obtained in a comparable arm's length transaction with a
               Person that is not an Affiliate.

                     Consolidation, Merger or Acquisition.
                     ------------------------------------ 

               Neither the Borrower nor any of its Subsidiaries shall merge or
               consolidate with or into any other Person, or make any
               acquisition of the business or assets of any other Person except:
               (i) any Subsidiary of the Borrower may merge into a Borrower or
               any wholly-owned Subsidiary of a Borrower; (ii) Investments to
               the extent permitted by Section 9.8 hereof; and (iii) Permitted
               Acquisitions.  For purposes hereof a "Permitted Acquisition" is
                                                     ---------------------    
               an acquisition which satisfies the following requirements: (A) if
               it involves an asset purchase, stock purchase or a merger or
               consolidation, upon the consummation of which the surviving or
               acquired party shall be the Borrower or a Subsidiary of the
               Borrower; (B) at the time of such acquisition and after giving
               effect thereto no Event of Default shall have occurred and be
               continuing; and (C) the conditions set forth in Section 9.2(b)
               hereof shall have been satisfied with respect to the proposed
               acquisition.

               In addition to the requirements set forth in Section 9.2(a), the
               following additional conditions must be satisfied with respect to
               each Permitted Acquisition:
<PAGE>
 
     1.1.1.16. Each company, business or Person to be acquired shall be engaged
               in the same or a related line of business to the then current
               businesses conducted by the Borrower and its Subsidiaries and
               shall have EBITDA with adjustments for certain one-time saving
               reasonably acceptable to the Agent for the twelve months
               immediately preceding the proposed acquisition date greater than
               $1.00;

     1.1.1.17. With respect to any individual proposed acquisition involving
               aggregate consideration in excess of $1,000,000, the Borrower
               will submit a pro forma Compliance Certificate to the Agent
               (which the Agent shall promptly thereafter forward to the
               Lenders) which shall demonstrate that on a pro forma basis and
               after giving effect to the proposed acquisition the Borrower will
               be in compliance with the financial covenants set forth in
               Section 10. hereof;

     1.1.1.18. All necessary consents, approvals, licenses, permissions,
               registrations or validations of any Governmental Authority or any
               other Person required for the consummation of the proposed
               acquisition shall have been obtained and shall be in full force
               and effect;

     1.1.1.19. With respect to any individual proposed acquisition involving an
               aggregate acquisition price in excess of $10,000,000 (including
               assumption of Indebtedness)/1/, such acquisition shall be subject
               to the review (but not the approval) of the Majority Lenders
               which review shall be completed within five (5) Banking Days
               after the Agent and each of the Lenders shall have received
               copies of the draft acquisition agreement for such proposed
               acquisition and the financial statements of the entity to be
               acquired (audited or reviewed to the extent available) provided,
               however, that the Borrower shall deliver to the Agent and each of
               the Lenders such additional information or documents as the Agent
               shall reasonably request, provided that any such additional
               request shall not extend or delay the running of the
               aforementioned five (5) Banking Day period; and

     1.1.1.20. Each new Subsidiary of the Borrower formed to make such
               acquisition and each Person to be acquired which becomes a
               Subsidiary of the Borrower shall agree to become a guarantor of
               the Obligations and shall have executed such instruments in
               connection therewith as the Agent and its counsel shall
               reasonably request, including without limitation a Subsidiary
               Guaranty and a Subsidiary Security Agreement.

               Disposition of Assets.  The Borrower shall not convey, sell,
               ---------------------                                       
               lease, transfer or otherwise dispose of any of their property,
               business or assets (including, without limitation, accounts
               receivable and leasehold assets), whether now owned or hereafter
               acquired, except for (i) equipment or other assets sold, leased,
               assigned or otherwise disposed of in the ordinary course of
               business; (ii) the sale of inventory in the ordinary course of
               business and (iii) other assets (excluding accounts receivable
               which may not be disposed of), provided that the aggregate book
                                              --------                        
               value of all assets disposed of pursuant to this clause (iii) in
               any year shall not exceed five percent 

_________________________
               /1/  Trade liabilities already excluded from definition of
                    Indebtedness.
<PAGE>
 
               (5%) of the consolidated total assets, determined on a pro forma
               basis for completed Permitted Acquisitions, of the Borrower as of
               the end of any such year.

               Indebtedness.  Neither the Borrower nor any of its Subsidiaries
               ------------                                                   
               shall create, incur, assume or suffer to exist any Indebtedness,
               except:

                               the Obligations;

               existing Indebtedness, including Subordinated Debt, if any,
               listed on Schedule A hereto;
                         ----------        

               Capital Lease Obligations in an aggregate amount not to exceed
               $250,000 at any one time outstanding; provided that after giving
                                                     --------                  
               effect to the incurrence of any such Capital Lease Obligations,
               no Default or Event of Default shall have occurred and be
               continuing;

               Subordinated Debt incurred by the Borrower after the date hereof;
               provided that, after giving effect to the incurrence of such
               --------                                                    
               Subordinated Debt, no Default or Event of Default shall have
               occurred and be continuing;

               purchase money Indebtedness for the purchase price of equipment
               and capital assets incurred in the ordinary course of business,
               provided that such Indebtedness does not exceed $250,000 in
               --------                                                   
               principal amount in the aggregate at any time outstanding;

               other Indebtedness that does not exceed an amount equal to 1.5%
               of Trailing Twelve Month Revenue (not including any other
               Indebtedness permitted by this Section 9.4); and
                                              -----------      

               Indebtedness owing by the Borrower to one of its Subsidiaries or
               to the Borrower from one of its Subsidiaries.

               Guarantees.  Neither the Borrower or any of its Subsidiaries
               ----------                                                  
               shall create, incur or suffer to exist any obligations in respect
               of Guarantees except for:

                                    the Subsidiary Guaranties;

               existing Guarantees, if any, listed on Schedule A hereto;
                                                      ----------        

               Guarantees entered into after the date hereof in connection with
               Capital Lease Obligations and Indebtedness permitted under
               Section 9.4.

               Guarantees entered into by Borrower whereby it guarantees the
               performance of any of its Subsidiaries under leases of office
               space or dental practice space.

               Liens.  Neither the Borrower nor any of its Subsidiaries shall
               -----                                                         
               create, incur, assume or suffer to exist any Lien on any of its
               properties or assets, except the following (collectively,
               "Permitted Liens"):
                ---------------   
<PAGE>
 
               Liens for taxes, fees, assessments and other governmental charges
               not delinquent or being contested in good faith and by proper
               proceedings, as to which adequate accruals are maintained on the
               books of the Borrower in accordance with GAAP;

               carriers', warehousemen's, mechanics', materialmen's, landlord's
               or similar liens imposed by law incurred in the ordinary course
               of business in respect of obligations not overdue, or being
               contested in good faith and by proper proceedings and as to which
               adequate accruals with respect thereto are maintained on the
               books of the Borrower in accordance with GAAP;

               pledges or deposits in connection with workers' compensation,
               unemployment insurance and other types of social security
               legislation;

               security deposits made to secure the performance of leases,
               licenses and statutory obligations incurred in the ordinary
               course of business;

               Liens in favor of the Agent for the benefit of the Lenders;

               existing Liens, if any, listed on Schedule A hereto; provided
                                                 ----------         --------
               that no such Lien is spread to cover any additional property
               after the date hereof, and that the principal amount of the
               Indebtedness secured thereby is not increased; and

               Liens securing (i) Indebtedness for the purchase price of
               property or the refinancing thereof (provided such refinancing
               does not increase the amount of such Indebtedness) to the extent
               permitted by Section 9.4(e) or (ii) Indebtedness permitted by
               Sections 9.4(c) or 9.4(f), provided that in each such case (x)
                                          --------                           
               each such Lien is given solely to secure the purchase price of
               such property (or the refinancing thereof), does not extend to
               any other property and is given at the time of acquisition of
               such property, and (y) the Indebtedness secured thereby does not
               exceed the lesser of the cost of such property or its fair market
               value at the time of acquisition.

               Restricted Payments.  Neither the Borrower nor any of its
               -------------------                                      
               Subsidiaries shall declare or make any Restricted Payment, except
               that (i) the Subsidiaries may declare and make cash dividends to
               the Borrower and (ii) the Borrower may make payments to Gregory
               A. Serrao for the repurchase of stock of the Borrower held by him
               pursuant to Section 12 of his Employment and Non-Competition
               Agreement with the Company dated as of January 8, 1996, provided,
               however, that the Borrower shall not use proceeds of Revolving
               Credit Loans to finance any such repurchase and any such
               repurchase shall have been approved by the Board of Directors of
               the Borrower.

               Investments.  Subject to the provisions of Section 9.2, neither
               -----------                                                    
               the Borrower nor any of its Subsidiaries shall make, maintain or
               acquire any Investment in any Person other than:

               marketable obligations issued or guaranteed by the United States
               of America having a maturity of one year or less from the date of
               purchase;
<PAGE>
 
               certificates of deposit, eurodollar time deposits, commercial
               paper or any other obligations of any Lender or of any other bank
               or savings and loan with a minimum capital surplus of
               $100,000,000, with a maturity of less than one year from the date
               of such Investment;

               commercial paper with maturities of not more than 90 days having
               the highest rating then given by Moody's Investors Services, Inc.
               or Standard & Poor's Corporation;

               repurchase obligations with a term of not more than seven days
               for underlying securities of the types described in subparagraph
               (a) above entered into with any bank with a minimum capital
               surplus of $100,000,000;

               shares in money market mutual funds substantially all the assets
               of which are comprised of securities and other obligations of the
               types described in subparagraphs (a) through (d) above;

               depository accounts at any Lender;

               stock or obligations issued to the Borrower or any Subsidiary
               thereof in settlement of claims against others by reason of an
               event of bankruptcy or a composition or the readjustment of debt
               or a reorganization of any debtor of the Borrower or such
               Subsidiary;

               currently existing Investments set forth on Schedule A;
                                                           ---------- 

               Investments by the Borrower in its Subsidiaries; and

               Investments in stock of publicly traded companies provided that
               the initial aggregate amount of cash so invested shall not exceed
               $50,000 in the aggregate.

               ERISA.  The Borrower will not permit any Plan maintained by the
               -----                                                          
               Borrower or by any member of the Controlled Group to:  (a) engage
               in any "prohibited transaction" (ERISA (S)2003(c)); (b) fail to
               report to the Agent a "reportable event" (ERISA (S)4043) within
               30 days after its occurrence or as to any reportable event as to
               which the 30-day notice period requirement of Section 4043(b) of
               Title IV of ERISA has been waived by the PBGC, within 30 days of
               such time as the Borrower is requested to notify the PBGC of such
               reportable event; (c) incur any "accumulated funding deficiency"
               (ERISA (S)302); (d) terminate its existence at any time in a
               manner which could result in the imposition of a Lien on the
               property of the Borrower or any Subsidiary thereof; or (e) fail
               to report to the Agent any "complete withdrawal" or "partial
               withdrawal" by the Borrower or an affiliate from a "multiemployer
               plan" (ERISA (S)(S)4203, 4205, and 4001, respectively).  The
               quoted terms are defined in the respective sections of ERISA
               cited above.

               Fiscal Year.  The Borrower and its Subsidiaries shall not change
               -----------                                                     
               their fiscal year without giving the Agent notice in writing at
               least forty-five (45) days prior to the effective date of such
               change and negotiating and 
<PAGE>
 
               reaching agreement with the Majority Lenders as to any changes to
               the financial covenants set forth in Section 10 as may be
               occasioned thereby in the reasonable judgment of the Majority
               Lenders.

                             Financial Covenants.
                             ------------------- 

               The Borrower covenants and agrees that so long as this Agreement
               is in effect and until the Notes, together with all interest
               thereon and all other Obligations of the Borrower to the Lenders
               are paid or satisfied in full:

               Debt Coverage.  The Borrower will not permit the ratio of Total
               -------------                                                  
               Debt to Adjusted EBITDA to exceed 3.0 to 1.0 in each case, as
               determined at the end of each fiscal quarter for the four
               quarters then ended.
 
               Fixed Charges Coverage.  The Borrower will not permit the ratio
               ----------------------                                         
               of Adjusted EBITDA plus Rental Payments to Fixed Charges to be
                                  ----                                       
               less than 1.25 to 1:00 as determined at the end of each fiscal
               quarter for the four quarters then ended.

               Minimum Net Worth.  The Borrower shall at all times maintain Net
               -----------------                                               
               Worth at the end of any fiscal quarter in an amount of not less
               than (i) the Net Worth of the Borrower at September 30, 1998
                                                                           
               minus (ii) $2,000,000, plus (iii) fifty percent (50%) of
               -----                  ----                             
               cumulative consolidated Net Income for the period (taken as a
               single period) from September 30, 1998 through the end of such
               quarter, provided, that for purposes of this clause (iii) only
                        --------                                             
               positive consolidated Net Income shall be included and any net
               losses shall be disregarded, plus (iv) one hundred percent (100%)
                                            ----                                
               of the net proceeds of any public offering by the Borrower of
               shares of its capital stock.

                              Events of Default.
                              ----------------- 

               Events of Default.  The occurrence of any of the following events
               -----------------                                                
               shall be an "Event of Default" hereunder:
                            ----------------            

               The Borrower shall default (i) in the due and punctual payment of
               principal of any Loan; or (ii) in the payment of interest on any
               Loan or in the payment of any other amount due under any Loan
               Document and such default shall continue for more than five (5)
               Business Days after such payment was due; or

               Any representation, warranty or statement made herein or any
               other Loan Document, or in any certificate or statement furnished
               pursuant to or in connection herewith or therewith, shall prove
               to be incorrect, misleading or incomplete in any material respect
               on the date as of which made or deemed made; or

               The Borrower shall default in the performance or observance of
               any term, covenant or agreement on its part to be performed or
               observed pursuant to Sections 8.1 (but only to the extent such
               default relates to Regulation U) 8.2, 8.6, 8.10, 9.2, 9.7, 9.9,
               9.10, and 10 hereof; or
<PAGE>
 
               The Borrower shall default in the performance or observance of
               any term, covenant or agreement on its part to be performed or
               observed pursuant to any of the provisions of this Agreement or
               any other Loan Document (other than those referred to in
               paragraphs (a) through (c) above) and such default shall continue
               unremedied for a period of thirty (30) days after the occurrence
               of such Default; or

               Any obligation of the Borrower or any of its Subsidiaries in
               respect of any Indebtedness (other than the Notes) or any
               Guarantee, including, without limitation, any Indebtedness owing
               to the Agent or any Lender, which involves an aggregate amount in
               excess of $500,000 shall be declared to be or shall become due
               and payable prior to the stated maturity thereof and shall not be
               paid, or such Indebtedness or Guarantee shall not be paid as and
               when the same becomes due and payable, or there shall occur and
               be continuing any default under any instrument, agreement or
               evidence of indebtedness relating to any such Indebtedness the
               effect of which is to permit the holder or holders of such
               instrument, agreement or evidence of indebtedness, or a trustee,
               agent or other representative on behalf of such holder or
               holders, to cause such Indebtedness to become due prior to its
               stated maturity and shall not be paid; or

               The Borrower or any of its Subsidiaries thereof shall (i) apply
               for or consent to the appointment of, or the taking of possession
               by, a receiver, custodian, trustee or liquidator of itself or of
               all or a substantial part of its property, (ii) make a general
               assignment for the benefit of its creditors, (iii) commence a
               voluntary case under the Bankruptcy Code, (iv) file a petition
               seeking to take advantage of any other law relating to
               bankruptcy, insolvency, reorganization, winding-up, or
               composition or readjustment of debts, (v) fail to controvert in a
               timely and appropriate manner, or acquiesce in writing to, any
               petition filed against it in an involuntary case under the
               Bankruptcy Code, or (vi) take any corporate action for the
               purpose of effecting any of the foregoing; or

               A proceeding or case shall be commenced, without the application
               or consent of the Borrower or any of its Subsidiaries in any
               court of competent jurisdiction, seeking (i) its liquidation,
               reorganization, dissolution or winding-up, or the composition or
               readjustment of its debts, (ii) the appointment of a trustee,
               receiver, custodian, liquidator or the like of the Borrower or
               any of its Subsidiaries or of all or any substantial part of its
               assets, or (iii) similar relief in respect of the Borrower or any
               of its Subsidiaries under any law relating to bankruptcy,
               insolvency, reorganization, winding-up, or composition or
               adjustment of debts, and such proceeding or case shall continue
               undismissed, or an order, judgment or decree approving or
               ordering any of the foregoing shall be entered and continue
               unstayed and in effect, for a period of 60 days; or an order for
               relief against the Borrower or any of its Subsidiaries shall be
               entered in an involuntary case under the Bankruptcy Code; or

               A judgment or judgments for the payment of money in excess of
               $500,000 (net of insurance proceeds) in the aggregate shall be
               rendered against the Borrower or any of its Subsidiaries and any
               such judgment or judgments 
<PAGE>
 
               shall not have been vacated, discharged, stayed or bonded pending
               appeal within thirty (30) days from the entry thereof; or

               The Borrower or any member of the Controlled Group shall fail to
               pay when due an amount or amounts aggregating in excess of
               $500,000 which it is obligated to pay to the PBGC or to a Plan
               under Title IV of ERISA; or a notice of intent to terminate a
               Plan or Plans having aggregate Unfunded Liabilities in excess of
               $500,000 shall be filed under Title IV of ERISA by the Borrower
               or any member of the Controlled Group, any plan administrator or
               any combination of the foregoing; or the PBGC shall institute
               proceedings under Title IV of ERISA to terminate or to cause a
               trustee to be appointed to administer any such Plan or Plans or a
               proceeding shall be instituted by a fiduciary of any such Plan or
               Plans against the Borrower or any member of the Controlled Group
               to enforce Sections 515 or 4219(c)(5) of ERISA; or a condition
               shall exist by reason of which the PBGC would be entitled to
               obtain a decree adjudicating that any such Plan or Plans must be
               terminated; or there shall occur a complete or partial withdrawal
               form, or a default, within the meaning of Section 4219(c)(5) of
               ERISA, with respect to, one or more Multiemployer Plans which
               could cause the Borrower or one or more members of the Controlled
               Group to incur a current payment obligation in excess of
               $500,000; or

               Pension plans maintained by the Borrower or any member of the
               Funding Standard Controlled Group or to which the Borrower or any
               member of the Funding Standard Controlled Group is obligated to
               contribute shall incur in the aggregate an "accumulated funding
               deficiency", within the meaning of Section 302 of ERISA, in
               excess of $500,000, or

               Any Security Instrument shall cease for any reason to be in full
               force and effect or shall cease to be effective to grant a
               perfected security interest in a material portion of the
               Collateral described in such Security Instrument with the
               priority stated to be granted thereby;
 
               Any Significant Subsidiary shall revoke its Subsidiary Guaranty
               or any Subsidiary Guaranty or Subsidiary Security Document to
               which a Significant Subsidiary is a party shall cease for any
               reason to be in full force and effect; or

               The individuals serving as Chief Executive Officer and Chief
               Financial Officer of the Borrower on the Closing Date shall both
               cease, for any reason (including, without limitation,
               resignation, removal or death), to be executive officers of the
               Borrower within any six month period, unless successors
               reasonably acceptable to the Majority Lenders replace such
               individuals within a reasonable period of time after they shall
               have ceased to serve.

               Remedies Upon an Event of Default.  If any Event of Default shall
               ---------------------------------                                
               have occurred and be continuing, the Agent may (and, if directed
               by Majority Lenders, shall) by notice (a) declare the Commitments
               terminated (whereupon the Commitments shall be terminated) and/or
               (b) declare the principal amount then outstanding of, and the
               accrued interest on, the 
<PAGE>
 
               Loans and commitment fees and all other amounts payable hereunder
               and under the Notes to be forthwith due and payable, whereupon
               such amounts shall be and become immediately due and payable,
               without further notice (including, without limitation, notice of
               intent to accelerate), presentment, demand, protest or other
               formalities of any kind, all of which are hereby expressly waived
               by the Borrower; provided that in the case of the occurrence of
                                --------            
               an Event of Default with respect to the Borrower referred to in
               clauses (f) and (g) of Section 11.1, the Commitments shall be
               automatically terminated and the principal amount then
               outstanding of, and the accrued interest on, the Loans and
               commitment fees and all other amounts payable hereunder and under
               the Notes shall be and become automatically and immediately due
               and payable, without notice (including, without limitation,
               notice of intent to accelerate), presentment, demand, protest or
               other formalities of any kind, all of which are hereby expressly
               waived by the Borrower.

                          The Agent And The Co-Agent.
                          -------------------------- 

                      Appointment, Powers and Immunities.
                      ---------------------------------- 

               Each Lender and the Issuing Bank hereby irrevocably appoints and
               authorizes the Agent to act as its agent hereunder and under the
               other Loan Documents with such powers as are specifically
               delegated to the Agent by the terms hereof and thereof, together
               with such other powers as are reasonably incidental thereto.

               Each Lender and the Issuing Bank hereby irrevocably appoints and
               authorizes the Co-Agent to act as its co-agent hereunder and
               under the other Loan Documents. Each Lender and the Issuing Bank
               irrevocably authorizes the Co-Agent to take such action on behalf
               of each of the Lenders and the Issuing Bank and to exercise all
               such powers as are expressly delegated to such Co-Agent hereunder
               and in the other Loan Documents and all related documents or by
               the Agent, together with such other powers as are reasonably
               incidental thereto.  The Co-Agent shall not have any duties or
               responsibilities or any fiduciary relationship with the Agent,
               any Lender or Issuing Bank except as expressly set forth in this
               Agreement.  All references hereunder to the rights and
               obligations of the Agent shall also be deemed to apply to the Co-
               Agent to the extent that the duties or actions of the Agent to
               which such rights or obligations relate have been delegated by
               the Agent to the Co-Agent.

               The Agent and the Co-Agent (which terms as used in this Section
               12 shall include reference to their Affiliates and their own and
               their Affiliates' officers, directors, employees and agents):
               (a) shall have no duties or responsibilities except those
               expressly set forth in this Agreement and the other Loan
               Documents, and shall not by reason of this Agreement or any other
               Loan Document be a trustee for any Lender; (b) shall not be
               responsible to the Lenders for any recitals, statements,
               representations or warranties contained in this Agreement or any
               other Loan Document, or in any certificate or other document
               referred to or provided for in, or received by any of them under,
               this Agreement or any other Loan Document, or for the value,
               validity, effectiveness, genuineness, 
<PAGE>
 
               enforceability or sufficiency of this Agreement or any other Loan
               Document or any other document referred to or provided for herein
               or therein or for any failure by the Borrower or any other Person
               to perform any of its obligations hereunder or thereunder; (c)
               shall not be required to initiate or conduct any litigation or
               collection proceedings hereunder or under any other Loan Document
               except to the extent requested by the Majority Lenders, and (d)
               shall not be responsible for any action taken or omitted to be
               taken by them hereunder or under any other Loan Document or any
               other document or instrument referred to or provided for herein
               or therein or in connection herewith or therewith, except for
               their own gross negligence or willful misconduct. The Agent and
               the Co-Agent may employ agents and attorneys-in-fact and shall
               not be responsible for the negligence or misconduct of any such
               agents or attorneys-in-fact selected by it with reasonable care.

               Reliance.  The Agent and the Co-Agent shall be entitled to rely
               --------                                                       
               upon any certification, notice or other communication (including
               any thereof by telephone, telex, telegram or cable) believed by
               them to be genuine and correct and to have been signed or sent by
               or on behalf of the proper Person or Persons, and upon advice and
               statements of legal counsel, independent accountants and other
               experts selected by the Agent or the Co-Agent.  As to any matters
               not expressly provided for by this Agreement or any other Loan
               Document, the Agent and the Co-Agent shall in all cases be fully
               protected in acting, or in refraining from acting, hereunder and
               thereunder in accordance with instructions signed by the Majority
               Lenders (or if required by Section 13.1 hereof, by all of the
                                          ------------                      
               Lenders), and such instructions of the Majority Lenders and any
               action taken or failure to act pursuant thereto shall be binding
               on all of the Lenders.

               Defaults.  The Agent and the Co-Agent shall not be deemed to have
               --------                                                         
               knowledge of the occurrence of a Default (other than the non-
               payment of principal of or interest on Loans) unless the Agent or
               the Co-Agent has received notice from a Lender or the Borrower
               specifying such Default and stating that such notice is a "Notice
               of Default".  In the event the Co-Agent receives such a notice of
               the occurrence of a Default, it shall give prompt notice thereof
               to the Agent.  In the event that the Agent receives such a notice
               of the occurrence of a Default, the Agent shall give prompt
               notice thereof to the Lenders (and shall give each Lender prompt
               notice of each such non-payment).  The Agent shall (subject to
               Section 12.7 hereof) take such action with respect to such
               ------------                                              
               Default as shall be directed by the Majority Lenders (or if
               required by Section 13.1 hereof, by all of the Lenders), provided
                           ------------                                 --------
               that, unless and until the Agent shall have received such
               directions, the Agent may (but shall not be obligated to) take
               such action, or refrain from taking such action, with respect to
               such Default as it shall deem advisable in the best interests of
               the Lenders.

               Rights as a Lender.  Subject to the provisions of Section 4.6(b),
               ------------------                                               
               with respect to their Commitments and the Loans made by them,
               Fleet and BankBoston, N.A. in their capacities as Lenders
               hereunder shall have the same rights and powers hereunder as any
               other Lender and may exercise the same as though they were not
               acting as the Agent or the Co-Agent, and 
<PAGE>
 
               the term "Lender" or "Lenders" shall, unless the context
               otherwise indicates, include Fleet and BankBoston, N.A. in their
               individual capacities. The Agent or the Co-Agent may (without
               having to account therefor to any Lender) accept deposits from,
               lend money to and the Co-Agent generally engage in any kind of
               banking, trust or other business with the Borrower (and any of
               their Affiliates) as if they were not acting as the Agent and the
               Co-Agent, and the Agent and the Co-Agent may accept fees and
               other consideration from the Borrower (in addition to the agency
               fees and arrangement fees heretofore agreed to between the
               Borrower and the Agent and Co-Agent) for services in connection
               with this Agreement or otherwise without having to account for
               the same to the Lenders.

               Events.  The Lenders agree to indemnify the Agent and the Co-
               ------                                                      
               Agent (to the extent not reimbursed under Section 13.5 hereof),
                                                         ------------         
               but without limiting the obligations of the Borrower under said
               Section 13.5, ratably in accordance with their respective
               ------------                                             
               Commitments, for any and all liabilities, obligations, losses,
               damages, penalties, actions, judgments, suits, costs, expenses or
               disbursements of any kind and nature whatsoever which may be
               imposed on, incurred by or asserted against the Agent and the Co-
               Agent in any way relating to or arising out of this Agreement or
               any other Loan Document or any other documents contemplated by or
               referred to herein or therein or the transactions contemplated
               hereby or thereby (including, without limitation, the costs and
               expenses which the Borrower is obligated to pay under Section
                                                                     -------
               13.5 hereof but excluding, unless a Default has occurred and is
               ----                                                           
               continuing, normal administrative costs and expenses incident to
               the performance of its agency duties hereunder) or the
               enforcement of any of the terms hereof or thereof or of any such
               other documents, provided that no Lender shall be liable for any
                                --------                                       
               of the foregoing to the extent they arise from the gross
               negligence or willful misconduct of the party to be indemnified
               and provided further that nothing in this Section 12.5 shall
                   -------- -------                      ------------      
               require any Lender to reimburse the Agent and the Co-Agent for
               internal overhead.

               Non-Reliance on Agent or the Co-Agent and Other Lenders.  Each
               -------------------------------------------------------       
               Lender agrees that it has, independently and without reliance on
               the Agent and the Co-Agent or any other Lender, and based on such
               documents and information as it has deemed appropriate, made its
               own credit analysis of the Borrower and decision to enter into
               this Agreement and that it will, independently and without
               reliance upon the Agent or the Co-Agent or any other Lender, and
               based on such documents and information as it shall deem
               appropriate at the time, continue to make its own analysis and
               decisions in taking or not taking action under this Agreement or
               any of the other Loan Documents.  The Agent and the Co-Agent
               shall not be under any obligation to any Lender to ascertain or
               to inquire as to the performance or observance by the Borrower of
               this Agreement or any of the other Loan Documents or any other
               document referred to or provided for herein or therein or to
               inspect the properties or books of the Borrower.  Except for
               notices, reports and other documents and information expressly
               required to be furnished to the Lenders by the Agent and the Co-
               Agent hereunder or the other Loan Documents, the Agent and the
               Co-Agent shall not have any duty or responsibility to provide any
               Lender with any credit or other information concerning the
               affairs, financial condition or business 
<PAGE>
 
               of the Borrower (or any of its Affiliates) which may come into
               the possession of the Agent and the Co-Agent.

               Failure to Act.  Except for action expressly required of the
               --------------                                              
               Agent or the Co-Agent hereunder and under the other Loan
               Documents, the Agent and the Co-Agent shall in all cases be fully
               justified in failing or refusing to act hereunder and thereunder
               unless it shall receive further assurances to its satisfaction by
               the Lenders of their indemnification obligations under Section
                                                                      -------
               12.5 hereof against any and all liability and expense which may
               ----                                                           
               be incurred by it by reason of taking or continuing to take any
               such action.

               Removal of Agent or Co-Agent.  Subject to the appointment and
               ----------------------------                                 
               acceptance of a successor Agent or Co-Agent as provided below,
               the Agent or Co-Agent may be removed at any time with or without
               cause by the Majority Lenders.  Upon any such removal the
               Majority Lenders shall have the right to appoint a successor
               Agent or Co-Agent reasonably acceptable to the Borrower (and, in
               the case of a successor Co-Agent, reasonably acceptable to the
               Agent).  If no successor Agent or Co-Agent shall have been so
               appointed by the Majority Lenders and shall have accepted such
               appointment within 30 days after the Majority Lenders' removal of
               the retiring Agent or Co-Agent (the "Notice Date"), then the
                                                    -----------            
               retiring Agent or Co- Agent may, on behalf of the Lenders,
               appoint a successor Agent or Co-Agent reasonably acceptable to
               the Borrower (and, in the case of successor Co-Agent, reasonably
               acceptable to the Agent).  Any successor Agent or Co-Agent shall
               be (i) a Lender or (ii) if no Lender has accepted such
               appointment within 30 days after the Notice Date, a bank which
               has an office in Boston, Massachusetts with a combined capital
               and surplus of at least $200,000,000.  Upon the acceptance of any
               appointment as Agent or Co-Agent hereunder by a successor Agent
               or Co-Agent, such successor Agent or Co-Agent shall thereupon
               succeed to and become vested with all the rights, powers,
               privileges and duties of the retiring Agent or Co-Agent, and the
               retiring Agent or Co-Agent shall be discharged from its duties
               and obligations hereunder.  After any retiring Agent or Co-
               Agent's removal hereunder as Agent or Co-Agent, the provisions of
               this Section 12 shall continue in effect for its benefit in
                    ----------                                            
               respect of any actions taken or omitted to be taken by it while
               it was acting as the Agent or Co-Agent.  The Agent or Co-Agent
               may upon notice thereof to the Borrower and the Lenders, but
               subject to the prior written consent of the Borrower, resign,  in
               which case the procedures for appointing a successor Agent or Co-
               Agent set forth in this Section 12.8 shall be followed as though
               the Agent or Co-Agent had been removed by the Majority Lenders.

               Collateral Sub-Agents.  Each Lender by its execution and delivery
               ---------------------                                            
               of this Agreement agrees, as contemplated by the Security
               Instruments, that, in the event it shall hold any Liquid
               Investments referred to therein, such Liquid Investments shall be
               held in the name and under the control of such Lender and such
               Lender shall hold such Liquid Investments as a collateral sub-
               agent for the Agent thereunder.

                                   General.
                                   ------- 
<PAGE>
 
               Amendments, Etc.  No amendment or waiver of any provision of this
               ---------------                                                  
               Agreement, the Notes, or any other Loan Document nor consent to
               any departure by the Borrower therefrom, shall in any event be
               effective unless the same shall be in writing and signed by the
               Majority Lenders and the Borrower, and then such waiver or
               consent shall be effective only in the specific instance and for
               the specific purpose for which given; provided that no amendment,
                                                     --------                   
               waiver or consent shall, unless in writing and signed by all the
               Lenders, do any of the following:  (i)  increase any Commitment
               of any of the Lenders or subject the Lenders to any additional
               obligations; (ii) reduce the principal of, or interest on, any
               Loan or fees hereunder; (iii) postpone any date fixed for any
               payment of principal of, or interest on, any Loan, or fee
               hereunder; (iv) change the percentage of any of the Commitments
               or of the aggregate unpaid principal amount of any of the Loans,
               or the number of Lenders, which shall be required for the Lenders
               or any of them to take any action under this Agreement; (v)
               change any provision contained in Sections 2.1, 4.12, through
                                                 -------- ---  ----         
               4.19, 13.5 or this Section 13.1 hereof; (vi) release any
               ----  ----         ------------                         
               substantial portion of the security for the Obligations of the
               Borrower under this Agreement or any Note, except for
               dispositions permitted under Sections 5.2 or 9.3 or release any
               Guarantor of any of its respective obligations under the
               Guarantors' Documents; (vii) modify the definition of "Majority
               Lenders" as set forth in Section 1.1; or (viii) in those
                                        -----------                    
               provisions where consent or approval by the Majority Lenders is
               required, eliminate the requirement of such consent or approval.
               Notwithstanding anything in this Section 13.1 to the contrary, no
                                                ------------                    
               amendment, waiver or consent shall be made with respect to
               Section 12 without the consent of the Agent.  Upon receipt of an
               ----------                                                      
               affidavit of an officer of Agent as to the loss, theft,
               destruction or mutilation of any Note or any other security
               document which is not of public record and in the case of any
               such loss, theft, destruction or mutilation, upon surrender and
               cancellation of any such Note or other Loan Document, Borrower
               will issue, in lieu thereof, a replacement Note or other Loan
               Document in the same principal amount thereof (to the extent
               applicable) and otherwise of like tenor.

               Notices, Etc.  Unless otherwise specified herein, all notices
               ------------                                                 
               hereunder to any party hereto shall be in writing and shall be
               deemed to have been given when delivered by hand, or when sent by
               electronic facsimile transmission or by telex, answer back
               received, or on the first Banking Day after delivery to any
               overnight delivery service, freight pre-paid, or three days after
               being sent by certified or registered mail, return receipt
               requested, postage pre-paid, and addressed to such party at its
               address indicated on Schedule 2 hereto; or at any other address
                                   -----------                                
               specified by such party in writing except that notices to the
               Agent pursuant to Section 4 shall not be effective until received
               by the Agent.

               No Waiver; Remedies.  No failure on the part of the Agent or the
               -------------------                                             
               Lenders to exercise, and no delay in exercising, any right
               hereunder, under the Notes or under any of the other Loan
               Documents shall operate as a waiver thereof; nor shall any single
               or partial exercise of any right hereunder, under the Notes or
               under any of the other Loan Documents preclude any other or
               further exercise thereof or the exercise of any other right.  The
<PAGE>
 
               remedies herein provided are cumulative and not exclusive of any
               remedies provided by law.

                               Right of Set-off.
                               ---------------- 

               Upon the occurrence and during the continuance of any Event of
               Default, each Lender is hereby authorized at any time and from
               time to time, to the fullest extent permitted by law, to set off
               and apply any and all deposits (general or special, time or
               demand, provisional or final) at any time held and other
               indebtedness at any time owing by such Lender to or for the
               credit or the account of the Borrower against any and all of the
               obligations of the Borrower now or hereafter existing under this
               Agreement and the Notes, irrespective of whether or not such
               Lender shall have made any demand hereunder.

               Each Lender agrees promptly to notify the Borrower, the Agent and
               the other Lenders after any such set-off and application,
               provided that the failure to give such notice shall not affect
               --------                                                      
               the validity of such set-off and application.  The rights of the
               Lenders under this Section 13.4 are in addition to other rights
                                  ------------                                
               and remedies (including, without limitation, other rights of set-
               off) which the Lenders may have.

                          Expenses; Indemnification.
                          ------------------------- 

               The Borrower shall pay on demand (i) any and all reasonable
               expenses incurred by the Agent in connection with the syndication
               of the Revolving Credit Loans; (ii) all out-of-pocket costs and
               expenses of the Agent in connection with the administration of
               this Agreement and the other Loan Documents, and any waiver or
               amendment of any provision hereof or thereof, including without
               limitation, the reasonable fees and disbursements of counsel for
               the Agent; and (iii) if any Default or Event of Default  occurs,
               all reasonable costs and expenses incurred by the Agent and the
               Lenders, including the reasonable fees and disbursements of
               counsel to the Agent and the Lenders, and of any field examiners,
               auditors, appraisers, environmental engineers or consultants, or
               investment banking firms retained by the Agent and the Lenders in
               connection with such Event of Default or collection, bankruptcy,
               insolvency and other enforcement proceedings related thereto.
               The Borrower agrees to pay, indemnify and hold the Agent and the
               Lenders harmless from, any and all recording and filing fees, and
               any and all liabilities with respect to, or resulting from any
               delay in paying, stamp, excise or other taxes, if any, which may
               be payable or determined to be payable in connection with the
               execution and delivery of or the consummation or administration
               of any of the transactions contemplated by, or any amendment,
               supplement or modification of, or any waiver or consent under or
               in respect of, this Agreement or the other Loan Documents, or any
               documents delivered pursuant hereto or thereto.

               The Borrower agree to indemnify the Agent and the Lenders and
               their respective officers and directors and hold the Agent and
               the Lenders and their respective officers and directors harmless
               from and against any and all liabilities, losses, damages,
               reasonable costs and expenses of any kind 
<PAGE>
 
               (including, without limitation, the reasonable fees and
               disbursements of counsel for the Agent and each Lender in
               connection with any investigative, administrative or judicial
               proceeding initiated by a third party, whether or not the Agent
               or any Lender shall be designated a party thereto) which may be
               incurred by the Agent or any Lender, relating to or arising out
               of this Agreement or any other Loan Document, or the existence of
               any Hazardous Substance on, in, or under any Borrower Group
               Property, or any violation of any applicable Environmental Laws
               for which the Borrower or any Subsidiary thereof has any
               liability or which occurs upon any Borrower Group Property, or
               the imposition of any Lien under any Environmental Laws, provided
                                                                        --------
               that neither the Agent nor any Lender shall not have the right to
               be indemnified hereunder for its own bad faith, gross negligence
               or willful misconduct as finally determined by a court of
               competent jurisdiction.

               The agreements in this Section 13.5 shall survive the repayment
                                      ------------                            
               of the Notes, and all other amounts payable under this Agreement
               and the other Loan Documents.

                            Successors and Assigns.
                            ---------------------- 

               This Agreement shall be binding upon and inure to the benefit of
               the parties hereto and their respective successors and assigns
               except that the Borrower may not assign its rights or obligations
               hereunder or under the Notes without the prior written consent of
               all of the Lenders.

               Each Lender shall have the right with the consent of the Agent
               and the Borrower (which consent in each case shall not be
               unreasonably withheld or delayed) to assign at any time any
               portion of its Commitment hereunder and its interests in the risk
               relating to any Revolving Credit Loans and Letter of Credit
               participations in an amount equal to or greater than $5,000,000
               to other Lenders or to banks or financial institutions acceptable
               to the Agent (each an "Assignee"), provided that any Lender which
                                      --------    --------                      
               proposes to assign less than its total Commitment must retain a
               Commitment of at least $5,000,000.  Each Assignee shall execute
               and deliver to the Agent and the Borrower a counterpart joinder
               in the form of Exhibit G hereto and shall pay to the Agent,
                              ---------                                   
               solely for the account of the Agent, an assignment fee of $3,500.
               Upon the execution and delivery of such counterpart joinder, (a)
               such Assignee shall, on the date and to the extent provided in
               such counterpart joinder, become a "Lender" party to this
               Agreement and the other Loan Documents for all purposes of this
               Agreement and the other Loan Documents and shall have all rights
               and obligations of a "Lender" with a Commitment as set forth in
               such counterpart joinder, and the transferor Lender shall, on the
               date and to the extent provided in such counterpart joinder, be
               released prospectively from its obligations hereunder and under
               the other Loan Documents to a corresponding extent (and, in the
               case of an assignment covering all of the remaining portion of an
               assigning Lender's rights and obligations under this Agreement,
               such transferor shall cease to be a party hereto but shall
               continue to be entitled to the benefits of Section 13.5 and to
               any interest or fees accrued for its account hereunder and not
               yet paid); (b) the assigning Lender shall promptly surrender its
               Notes to the Agent for cancellation 
<PAGE>
 
               and delivery to the Borrower, provided that if the assigning
               Lender has retained any Commitment, the Borrower shall execute
               and deliver to the Agent for delivery to such assigning Lender
               new Notes in the aggregate amount of the assigning Lender's
               retained Commitment; (c) the Borrower shall issue to the Assignee
               such Notes in the aggregate amount of such Assignee's Commitment
               dated the Closing Date or such other date as may be specified by
               such Assignee; (d) this Agreement shall be deemed appropriately
               amended to reflect (i) the status of such Assignee as a party
               hereto and (ii) the status and rights of the Lenders hereunder;
               and (e) the Borrower shall take such action as the Agent may
               reasonably request to perfect or maintain the perfection of any
               security interests contemplated by this Agreement or any other
               Loan Document in favor of the Agent or Lenders, including any
               Assignee which becomes a party to this Agreement.

               If the Assignee, or any Participant pursuant to Section 13.6(d)
               hereof, is organized under the laws of a jurisdiction other than
               the United States or any state thereof, such Assignee shall
               execute and deliver to the Borrower, simultaneously with or prior
               to such Assignee's execution and delivery of the counterpart
               joinder described above in Section 13.6(b) and such Participant
               shall execute and deliver to the Lender granting the
               participation, a United States Internal Revenue Service Form 4224
               or Form 1001 (or any successor form), appropriately completed,
               wherein such Assignee or Participant claims entitlement to
               complete exemption from United States Federal Withholding Tax on
               all interest payments hereunder and all fees payable pursuant to
               any of the Loan Documents.  The Borrower shall not be required to
               pay any increased amount to any Assignee or other Lender on
               account of taxes to the extent such taxes would not have been
               payable if the Assignee or Participant had furnished the Forms
               referenced in this Section 13.6(b) unless the failure to furnish
               such a Form results from (i) any act of or failure to act by any
               of the Borrower or (ii) the adoption of or change in any law,
               rule, regulation or guideline affecting such Assignee or
               Participant occurring (y) after the date on which any such
               Assignee executes and delivers the counterpart joinder and
               complies with all other applicable provisions of Section 13.6(b)
               or (z) after the date a Participant is granted its participation.

               Each Lender shall have the right, with the consent of the Agent
               (which consent shall not be unreasonably withheld or delayed), to
               grant participations, each in an amount equal to or greater than
               $5,000,000 to one or more banks or other financial institutions
               (each a "Participant") in all or any part of any Loans and Letter
                        -----------                                             
               of Credit participations owing to such Lender and the Notes held
               by such Lender.  Notwithstanding the foregoing, any participation
               granted by a Lender to an Affiliate of the granting Lender shall
               not be subject to either the consent of the Agent or the minimum
               participation amount.  Each Lender shall retain the sole right to
               approve, without the consent of any Participant, any amendment,
               modification or waiver of any provision of the Loan Documents,
               provided that the documents evidencing any such participation may
               --------                                                         
               provide that, except with the consent of such Participant, such
               Lender will not consent to (a) the reduction in or forgiveness of
               the stated principal of or rate of interest on or commitment fee
               with respect to the portion of any Revolving Credit Loan subject
               to such participation, (b) the extension or postponement of any
               stated date fixed for payment of principal or interest or
               commitment fee with respect to the portion of any Revolving
<PAGE>
 
               Credit Loan subject to such participation, or (c) the waiver or
               reduction of any right to indemnification of such Lender
               hereunder.  Notwithstanding the foregoing, no participation shall
               operate to increase the total Commitments hereunder or otherwise
               alter the substantive terms of this Agreement.  In the event of
               any such sale by a Lender of participating interests to a
               Participant, such Lender's obligations under this Agreement shall
               remain unchanged, such Lender shall remain solely responsible for
               the performance thereof, such Lender shall remain the holder of
               such Notes for all purposes under this Agreement and the Borrower
               and Agent shall continue to deal solely and directly with such
               Lender in connection with such Lender's rights and obligations
               under this Agreement.  Notwithstanding anything to the contrary
               contained herein, the Borrower agrees that provisions of Sections
               4.10 and 4.12 through 4.19 shall inure to the benefit of each
               Participant, and each Lender may enforce such provisions on
               behalf of any of its Participants; provided, however, in no event
                                                  --------                      
               shall the Borrower be required to pay to the Participants of a
               Lender and such Lender, in the aggregate, any amounts in excess
               of the total amount they would otherwise be obligated to pay to
               such Lender under the applicable section referred above had such
               Lender not granted participations pursuant to this Section
               13.6(d).

               Each Lender may furnish any information concerning the Borrower,
               its Subsidiaries and any other Loan Party in the possession of
               such Lender from time to time to assignees and participants
               (including prospective assignees and participants), provided,
               that such Lender shall require any such prospective or actual
               assignee or participant to maintain the confidentiality
               requirements of Section 13.15.  Notwithstanding any other
               provision of this Section 13.6, Fleet agrees for the benefit of
                                 ------------                                 
               the Borrower to retain for its own account a principal amount of
               the Loans and a portion of the Revolving Credit Commitment equal
               in the aggregate to at least 50% of the principal amount from
               time to time outstanding of the Loans and of the Revolving Credit
               Commitment.

               Severability.  Any provision of this Agreement which is
               ------------                                           
               prohibited, unenforceable or not authorized in any jurisdiction
               shall, as to such jurisdiction, be ineffective to the extent of
               such prohibition, unenforceability or non-authorization without
               invalidating the remaining provisions hereof or affecting the
               validity, enforceability or legality of such provision in any
               other jurisdiction.

               GOVERNING LAW.  THIS AGREEMENT SHALL BE GOVERNED BY, AND
               -------------                                           
               CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE COMMONWEALTH OF
               MASSACHUSETTS (WITHOUT REGARD TO CONFLICTS OF LAWS RULES).

               WAIVER OF JURY TRIAL.  THE AGENT, THE LENDERS AND THE BORROWER
               --------------------                                          
               KNOWINGLY, VOLUNTARILY AND INTENTIONALLY AGREE THAT NONE OF THEM
               NOR ANY ASSIGNEE OR SUCCESSOR SHALL (A) SEEK A JURY TRIAL IN 
<PAGE>
 
               ANY LAWSUIT, PROCEEDING, COUNTERCLAIM OR ANY OTHER ACTION BASED
               UPON, OR ARISING OUT OF, OR IN CONNECTION WITH THIS AGREEMENT,
               THE NOTES, ANY RELATED DOCUMENTS OR INSTRUMENTS, ANY COLLATERAL
               OR ANY COURSE OF CONDUCT, COURSE OF DEALINGS OR STATEMENTS
               (WHETHER VERBAL OR WRITTEN) OR ACTIONS OF ANY OF THEM, OR (B)
               SEEK TO CONSOLIDATE ANY SUCH ACTION WITH ANY OTHER ACTION IN
               WHICH A JURY TRIAL CANNOT BE OR HAS NOT BEEN WAIVED. THE
               PROVISIONS OF THIS PARAGRAPH HAVE BEEN FULLY DISCUSSED BY THE
               AGENT, THE LENDERS AND THE BORROWER, AND THESE PROVISIONS SHALL
               BE SUBJECT TO NO EXCEPTIONS. NEITHER THE AGENT, THE LENDERS NOR
               THE BORROWER HAS AGREED WITH OR REPRESENTED TO THE OTHER THAT THE
               PROVISIONS OF THIS PARAGRAPH WILL NOT BE FULLY ENFORCED IN ALL
               INSTANCES. THE BORROWER'S AGREEMENT TO THE FOREGOING CONSTITUTES
               A MATERIAL INDUCEMENT FOR THE AGENT, AND THE LENDERS TO ENTER
               INTO THIS AGREEMENT, FOR THE LENDERS TO MAKE THE LOANS AND FOR
               THE ISSUING BANK TO ISSUE LETTERS OF CREDIT.

               VENUE, CONSENT TO SERVICE OF PROCESS.  THE BORROWER ACCEPT FOR
               ------------------------------------                          
               THEMSELVES AND IN CONNECTION WITH THEIR PROPERTIES, GENERALLY AND
               UNCONDITIONALLY, THE EXCLUSIVE JURISDICTION OF ANY STATE OR
               FEDERAL COURT OF COMPETENT JURISDICTION IN THE COMMONWEALTH OF
               MASSACHUSETTS IN ANY ACTION, SUIT OR PROCEEDING OF ANY KIND
               AGAINST THEM WHICH ARISES OUT OF OR BY REASON OF THIS AGREEMENT,
               THE NOTES, ANY OTHER LOAN DOCUMENT, OR THE TRANSACTIONS
               CONTEMPLATED HEREBY OR THEREBY, IRREVOCABLY AGREE TO BE BOUND BY
               ANY FINAL JUDGMENT RENDERED BY ANY SUCH COURT IN ANY SUCH ACTION,
               SUIT OR PROCEEDING IN WHICH THEY SHALL HAVE BEEN SERVED WITH
               PROCESS IN THE MANNER HEREINAFTER PROVIDED, SUBJECT TO EXERCISE
               AND EXHAUSTION OF ALL RIGHTS OF APPEAL AND TO THE EXTENT THAT
               THEY MAY LAWFULLY DO SO, WAIVE AND AGREE NOT TO ASSERT, BY WAY OF
               MOTION, AS A DEFENSE OR OTHERWISE, IN SUCH ACTION, SUIT OR
               PROCEEDING ANY CLAIMS THAT THEY ARE NOT PERSONALLY SUBJECT TO THE
               JURISDICTION OF SUCH COURT, THAT THEIR PROPERTY IS EXEMPT OR
               IMMUNE FROM ATTACHMENT OR EXECUTION, THAT THE ACTION, SUIT OR
               PROCEEDING IS BROUGHT IN AN INCONVENIENT FORUM OR THAT THE VENUE
               THEREOF IS IMPROPER, AND AGREE THAT PROCESS MAY BE SERVED UPON
               THEM IN ANY SUCH ACTION, SUIT OR PROCEEDING IN THE MANNER
               PROVIDED BY CHAPTER 223A OF THE GENERAL LAWS OF MASSACHUSETTS,
               RULE 4 OF THE MASSACHUSETTS RULES OF CIVIL PROCEDURE OR RULE 4 OF
               THE FEDERAL RULES OF CIVIL PROCEDURE.
<PAGE>
 
               Additional Lenders.  The Borrower, each of the Lenders and the
               ------------------                                            
               Agent may at any time agree to add one or more lenders to this
               agreement pursuant to an instrument in writing specifying such
               new lender's "commitments" (and the reduction in commitments of
               the existing Lenders as a result thereof) in such manner as the
               Borrower, each of the Lenders and the Agent shall agree.  Upon
               the execution of such instrument (and the satisfaction of such
               conditions and other terms as shall therein be specified) such
               additional lender or lenders shall be deemed a "lender" or
               "lenders" for the purposes of this agreement and shall enjoy all
               rights and assume all obligations on the part of the Lenders set
               forth in this agreement, and the Lenders whose commitments are
               then being reduced shall be released from their commitments to
               the extent of such reduction.

               Pledge.  Any Lender may at any time pledge all or any portion of
               ------                                                          
               its rights under the Agreement including any portion of any of
               the Notes to any of the twelve (12) Federal Reserve Banks
               organized under Section 4 of the Federal Reserve Act, 12 U.S.C.
               Section 341.  No such pledge or enforcement thereof shall release
               Fleet from its obligations under any of the Loan Documents.

               Headings.  Section headings in this Agreement are included herein
               --------                                                         
               for convenience of reference only and shall not constitute a part
               of this Agreement for any other purpose.

               Counterparts.  This Agreement may be signed in one or more
               ------------                                              
               counterparts each of which shall constitute an original and all
               of which taken together shall constitute one and the same
               instrument.

               Confidentiality.  The Agent and each Lender and participant will
               ---------------                                                 
               keep confidential all Confidential Information (as defined below)
               and will not, without the Borrower's consent, disclose the same
               to any person other than to directors, officers, employees,
               agents or other representatives (including attorneys, accountants
               and financial advisers) of the Agent or any Lender or prospective
               Lender or any of their respective Affiliate and other than to any
               governmental agency or authority in accordance with applicable
               laws, rules or regulations or to any other third party as such
               Lender may deem reasonably necessary in connection with or in
               response to a subpoena, order, decree, notice of discovery or
               ruling which has been or on its face purports to have been
               issued, filed or served under authority of any court, tribunal,
               arbitration board, commission or similar entity in connection
               with any case or pending matter.  As used herein, the term
               "Confidential Information" shall mean only information prepared
               by the Borrower and furnished to the Lenders or obtained by the
               Lenders hereunder which consists of financial statements and
               projections of the Borrower, the Borrower's form of management
               agreement, business plan, and documents with respect to
               acquisitions by the Borrower or which is identified as
               confidential and which (i) is not ascertainable or obtained from
               public or published information or (ii) is not known or does not
               become known to the public (other than through a breach by the
               Lenders of this Section).
<PAGE>
 
               Amendment and Restatement.  This Agreement amends and restates in
               -------------------------                                        
               its entirety the Original Credit Agreement.  This Agreement and
               the other Loan Documents express the entire understanding of the
               parties with respect to the transactions contemplated hereby,
               except for the letter agreement dated August 5, 1998 between the
               Borrower and the Agent with respect to fees payable to the Agent,
               which letter agreement shall continue in full force and effect
               and shall not be superseded by any of the Loan Documents.
<PAGE>
 
               IN WITNESS WHEREOF, the parties hereto have caused this Agreement
               to be duly executed under seal and delivered by their respective
               officers thereunto duly authorized as of the date first above
               written.

                    AMERICAN DENTAL PARTNERS, INC.


                    By:  /s/ Ronald M. Levenson
                         -------------------------
                    Name:  Ronald M. Levenson
                    Title: Chief Financial Officer
 
 
                    FLEET NATIONAL BANK, Individually and as Agent


                    By: /s/ Ginger Stolzenthaler  
                        --------------------------
                    Ginger C. Stolzenthaler
                    Senior Vice President.


                    BANKBOSTON, N.A., Individually and as Co-Agent


                    By: /s/ Timothy G. Clifford
                        --------------------------
                    Name:  Timothy G. Clifford
                    Title: Director


                    U.S. BANK NATIONAL ASSOCIATION


                    By: /s/ Brian C. O'Neill
                        --------------------------
                    Name:  Brian C. O'Neill
                    Title: Vice President