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                                                                     EXHIBIT 4.5

REVOLVING BUSINESS CREDIT NOTE (LIBOR - BASED INTEREST RATE)
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Due September 30, 2001                                             $7,500,000.00

No.__________________                                   Date: September 30, 1999


PROMISE TO PAY. On or before September 30, 2001, for value received, American
Dental Technologies, Inc. (the "Borrower") promises to pay to Bank One,
Michigan (the "Bank"), or order, at any office of the Bank in the State of
Michigan, the sum of Seven Million Five Hundred Thousand and 00/100 DOLLARS
($7,500,000.00), or such lesser sum as is indicated on Bank records, plus
interest as provided below.

DEFINITIONS.

As used in this note, the following terms have the following respective
meanings.

     "APPLICABLE MARGIN" means with respect to any Floating Rate Loan 0% per
     annum and with respect to any Eurodollar Loan 1.5% per annum.

     "BUSINESS DAY" means a day other than a Saturday or Sunday, or other day
     that commercial banks in Detroit, Michigan are authorized or required to
     close under the laws of the State of Michigan and, with respect to any
     Eurodollar Loan, on which dealings in United States dollar deposits are
     carried out in the London interbank market.

     "CREDIT AGREEMENT" is defined in the paragraph entitled "Credit Agreement"
     below.

     "CREDIT FACILITY" is defined in the paragraph entitled "Credit Facility"
     below.

     "EURODOLLAR LOANS" means any Loan under the Credit Facility when and to the
     extent that its interest rate is determined by reference to the Eurodollar
     Rate.

     "EURODOLLAR RATE" means, with respect to any Eurodollar Loan and the
     related Interest Period, the per annum rate that is equal to the sum of:

     (A) the Applicable margin, plus

     (B) the rate obtained by dividing (i) the per annum rate of interest at
     which deposits in United States dollars for the Interest Period and in an
     aggregate amount comparable to the amount of the Loan are offered to Bank
     One, NA by other prime banks in the London interbank market, at
     approximately 11:00 a.m. London time on the second Business Day prior to
     the first day of the Interest Period by (ii) an amount equal to one minus
     the stated maximum rate (expressed as a decimal) of all reserve
     requirements (including, without limitation, any marginal, emergency,
     supplemental, special or other reserves) specified on the first day of such
     Interest Period by the Board of Governors of the Federal Reserve System (or
     any successor agency) for determining the maximum reserve requirement with
     respect to eurocurrency funding required to be maintained by a Federal
     Reserve System member bank;

     all as conclusively determined by the Bank, such sum to be rounded up, if
     necessary, to the nearest one-hundredth of one percent (1/100 of 1%).

     "FLOATING RATE" means the per annum rate of interest equal to the sum of
     the rate announced by the Bank as its "prime rate" in effect from time to
     time, which is not necessarily the lowest rate charged by the Bank to any
     of its customers, plus the Applicable Margin. Any change in the Bank's
     "prime rate" shall immediately change the Floating Rate.

     "FLOATING RATE LOAN" means any Loan under the Credit Facility when and to
     the extent that its interest rate is determined by reference to the
     Floating Rate.

     "INTEREST PERIOD" means, with respect to any Eurodollar Loan, a period of
     one, two, three or six months agreed upon by the Borrower and the Bank,
     commencing on the Business Day the Loan is made. If the Interest Period
     would end on a day which is not a Business Day, the Interest Period shall
     end on the next succeeding Business Day unless that

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     Business Day would fall in the next calendar month, in which case the
     Interest Period shall end on the immediately preceding Business Day.

     "Loan" and "Loans" are defined in the paragraph entitled "Credit Facility"
     below.

     "Loan Documents" means this note, the Credit Agreement, and any other
     documents executed in connection with this Credit Facility.

CREDIT FACILITY. The Bank has authorized a credit facility to the Borrower in a
principal amount not to exceed the face amount of this note. The credit
facility is in the form of loans (each, a "Loan", and, together, the "Loans")
made from time to time by the Bank to the Borrower. This note evidences the
Borrower's obligation to repay those Loans. The Bank shall, in the ordinary
course of business, make notations in its records of the date, amount, interest
rate and Interest Period of each Loan, the amount of each payment on the Loans,
and other information. Such records shall, in the absence of manifest error, be
conclusive as to the outstanding principal balance of and interest rate or
rates applicable to the Loans. The aggregate principal amount of debt evidenced
by this note shall be the amount reflected from time to time in the records of
the Bank but shall not exceed the face amount of this note. Until maturity, the
Borrower may borrow, pay down, and reborrow under this note so long as the
aggregate principal amount outstanding at any one time does not exceed the face
amount of this note.

CREDIT AGREEMENT. This note evidences a debt under the terms of a Line of
Credit Agreement (the "Credit Agreement") between the Bank and the Borrower
dated concurrently, and any amendments.

INTEREST RATES. Each Loan under the Credit Facility may be outstanding as
either a Floating Rate Loan or a Eurodollar Loan. The Borrower shall pay
interest to the Bank on the outstanding and unpaid principal amount of each
Floating Rate Loan at the Floating Rate and each Eurodollar Loan at the
Eurodollar Rate. Interest shall be calculated on the basis of the actual number
of days elapsed in a year of 360 days. In no event shall the interest rate
applicable to any Loan exceed the maximum rate allowed by law. Any interest
payment which would for any reason be deemed unlawful under applicable law
shall be applied to principal.

NOTICE AND MANNER OF BORROWING. The Borrower shall give the Bank written notice
(effective upon receipt) of any Loan under the Credit Facility no later than
11:00 A.M. Detroit time, one (1) Business Day before each Floating Rate Loan
and three (3) Business Days before each Eurodollar Loan specifying: (A) the
date of the Loan, (B) the amount of the Loan, (C) the type of the Loan
(Floating Rate Loan or Eurodollar Loan), and (D) in the case of a Eurodollar
Loan, the duration of the applicable Interest Period. Each Eurodollar Loan
shall be in a minimum amount of $500,000.00. All notices under this paragraph
are irrevocable. By the Bank's close of business on the date of the Loan and
upon fulfillment of the conditions set forth in the Credit Agreement, the Bank
shall make the Loan available to the Borrower in immediately available funds by
crediting the amount of the Loan to the Borrower's account with the Bank.

CONVERSION AND RENEWALS. The Borrower may elect from time to time to convert
one type of Loan into another or to renew any Loan by giving the Bank written
notice no later than 11:00 A.M. Detroit time one (1) Business Day before
conversion into a Floating Rate Loan and three (3) Business Days before
conversion into or removal of a Eurodollar Loan, specifying: (A) the renewal or
conversion date, (B) the amount of the Loan to be converted or renewed, (C) in
the case of conversion, the type of Loan to be converted into (Floating Rate
Loan or Eurodollar Loan), and (D) in the case of renewals of or conversion into
a Eurodollar Loan, the applicable Interest Period, provided that (i) the
minimum principal amount of each Eurodollar Loan outstanding after a renewal or
conversion shall be $500,000.00 and (ii) a Eurodollar Loan can only be
converted on the last day of the Interest Period for the Loan. All notices
given under this paragraph are irrevocable. If the Borrower fails to give the
Bank the notice specified above for the renewal or conversion of a Eurodollar
Loan by 11:00 a.m. Detroit time three (3) Business Days before the end of the
Interest Period for that Loan, the Loan shall automatically be converted to a
Floating Rate Loan on the last day of the Interest Period for the Loan.

INTEREST PAYMENTS. Interest on the Loans shall be paid as follows:

     (A) For each Floating Rate Loan, on the 30th day of each month beginning
         with the first full month following disbursement of the Loan and at the
         maturity of the Loan;

     (B) For each Eurodollar Loan, on the last day of the Interest Period for
         the Loan and, if the Interest Period is longer than three months, at
         three-month intervals beginning with the day three months from the date
         the Loan is disbursed.

OVERDUE AMOUNTS. Any principal amount not paid when due (at maturity, by
acceleration, or otherwise) shall bear interest thereafter until paid in full,
payable on demand, at a per annum rate equal to:

     (A) For each Floating Rate Loan a rate equal to the Floating Rate plus
         three percent (3%).

     (B) For each Eurodollar Loan, a rate equal to the Eurodollar Rate plus
         three percent (3%) from the time of default in payment of principal
         until the end of the then current Interest Period for the Loan and
         after that at a rate equal to the Floating Rate plus three percent
         (3%).



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PREPAYMENT. The Borrower may prepay all or any part of any Floating Rate Loan
at any time without premium or penalty. The Borrower may prepay any Eurodollar
Loan only at the end of an Interest Period.

FUNDING LOSS INDEMNIFICATION. Upon the Bank's request, the Borrower shall pay
the Bank amounts sufficient (in the Bank's reasonable opinion) to compensate it
for any loss, cost, or expense incurred as a result of:

     (A) Any payment of a Eurodollar Loan on a date other than the last day of
         the Interest Period for the Loan, including, without limitation,
         acceleration of the Loans by the Bank pursuant to this note or the
         Loan Documents; or

     (B) Any failure by the Borrower to borrow or renew a Eurodollar Loan on
         the date specified in the relevant notice from the Borrower to the
         Bank.

ADDITIONAL COSTS. If any applicable domestic or foreign law, treaty, government
rule or regulation now or later in effect (whether or not it now applies to the
Bank) or the interpretation or administration thereof by a governmental
authority charged with such interpretation or administration, or compliance by
the Bank with any guideline, request or directive of such an authority (whether
or not having the force of law), shall (A) affect the basis of taxation of
payments to the Bank of any amounts payable by the Borrower under this note or
the Loan Documents (other than taxes imposed on the overall net income of the
Bank by the jurisdiction or by any political subdivision or taxing authority
of the jurisdiction in which the Bank has its principal office), or (B) impose,
modify or deem applicable any reserve, special deposit or similar requirement
against assets of, deposits with or for the account of, or credit extended by
the Bank, or (C) impose any other condition with respect to this note or the
Loan Documents and the result of any of the foregoing is to increase the cost
to the Bank of maintaining any Eurodollar Loan or to reduce the amount of any
sum receivable by the Bank on such a Loan, or (D) affect the amount of capital
required or expected to be maintained by the Bank (or any corporation
controlling the Bank) and the Bank determines that the amount of such capital
is increased by or based upon the existence of the Bank's obligations under
this note or the Loan Documents and the increase has the effect of reducing the
rate of return on the Bank's (or its controlling corporation's) capital as a
consequence of the obligations under this note or the Loan Documents to a level
below that which the Bank (or its controlling corporation) could have achieved
but for such circumstances (taking into consideration its policies with respect
to capital adequacy) by an amount deemed by the Bank to be material, then the
Borrower shall pay to the Bank, from time to time, upon request by the Bank,
additional amounts sufficient to compensate the Bank for the increased cost or
reduced sum receivable. Whenever the Bank shall learn of circumstances
described in this section which are likely to result in additional costs to the
Borrower, the Bank shall give prompt written notice to Borrower of the basis
for and the estimated amount of any such anticipated additional costs. A
statement as to the amount of the increased cost or reduced sum receivable,
prepared in good faith and in reasonable detail by the Bank and submitted by
the Bank to the Borrower, shall be conclusive and binding for all purposes
absent manifest error in computation.

ILLEGALITY. If any applicable domestic or foreign law, treaty, rule or
regulation now or later in effect (whether or not it now applies to the Bank)
or the interpretation of administration thereof by a governmental authority
charged with such interpretation or administration, or compliance by the Bank
with any guideline, request or directive of such an authority (whether or not
having the force of law), shall make it unlawful or impossible for the Bank to
maintain or find the Eurodollar Loans, then, upon notice to the Borrower by the
Bank, the outstanding principal amount of the Eurodollar Loans, together with
accrued interest and any other amounts payable to the Bank under this note or
the Loan Documents on account of the Eurodollar Loans shall be repaid (A)
immediately upon the Bank's demand if such change or compliance with such
requests, in the Bank's judgment, requires immediate repayment, or (B) at the
expiration of the last Interest Period to expire before the effective date of
any such change or request provided, however, that subject to the terms and
conditions of this note and the Loan Documents the Borrower shall be entitled
to simultaneously replace the entire outstanding balance of any Eurodollar Loan
repaid in accordance with this section with a Floating Rate Loan in the same
amount.

INABILITY TO DETERMINE INTEREST RATE. If the Bank determines that (A)
quotations of interest rates for the relevant deposits referred to in the
definition of Eurodollar Rate are not being provided in the relevant amounts or
for the relevant maturities for purposes of determining the interest rate on a
Eurodollar Loan as provided in this note, or (B) the relevant interest rates
referred to in the definition of Eurodollar Rate do not accurately cover the
cost to the Bank of making or maintaining Eurodollar Loans, then the Bank shall
forthwith give notice of such circumstances to the Borrower, whereupon (1) the
obligation of the Bank to make Eurodollar Loans shall be suspended until the
Bank notifies the Borrower that the circumstances giving rise to the suspension
no longer exists, and (2) the Borrower shall repay in full the then
outstanding principal amount of each Eurodollar Loan, together with accrued
interest, on the last day of the then current Interest Period applicable to the
Loan, provided, however, that, subject to the terms and conditions of this note
and the Loan Documents, the Borrower shall be entitled to simultaneously
replace the entire outstanding balance of any Eurodollar Loan repaid in
accordance with this section with a Floating Rate Loan in the same amount.

OBLIGATIONS DUE ON NON-BUSINESS DAY. Whenever any payment under this note
becomes due and payable on a day that is not a Business Day, if no event of
acceleration has occurred and is continuing, the maturity of the payment
shall be extended to the next succeeding Business Day, except, in the case of a
Eurodollar Loan, if the result of the extension would be to extend the payment
into another calendar month, the payment must be made on the immediately
preceding Business Day.

SECURITY. To secure the payment of this note and all other present or future
liabilities of the Borrower to the Bank, whether several, joint, or joint and
several, the Borrower pledges and grants to the Bank a continuing security
interest in the following described property and all of its additions,
substitutions, increments, proceeds and products, whether now owned or later
acquired ("Collateral"):



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1.   All securities and other property of the Borrower in the custody,
     possession or control of the Bank (other than property held by the Bank
     solely in a fiduciary capacity);

2.   All property or securities declared or acknowledged to constitute security
     for any past, present or future liability of the Borrower to the Bank;

3.   All balances of deposit accounts of the Borrower with the Bank;

4.   The following additional property: all of the Borrower's present and future
     accounts, chattel paper and general intangibles; all of the Borrower's
     present and future inventory and equipment, wherever located; all of the
     Borrowers, patent's copyrights and trademarks.

BANK'S RIGHT TO SETOFF.  The Bank shall have the right at any time to apply its
own debt or liability to the Borrower or to any other party liable on this note
in whole or partial payment of this note or other present or future
liabilities, without any requirement of mutual maturity.

REPRESENTATIONS BY BORROWER.  Each Borrower represents: (a) that the execution
and delivery of this note and the performance of the obligations it imposes do
not violate any law, conflict with any agreement by which it is bound, or
require the consent or approval of any governmental authority or any third
party; (b) that this note is a valid and binding agreement, enforceable
according to its terms; and (c) that all balance sheets, profit and loss
statements, and other financial statements furnished to the Bank are accurate
and fairly reflect the financial condition of the organizations and persons to
which they apply on their effective dates, including contingent liabilities of
every type, which financial condition has not changed materially and adversely
since those dates. Each Borrower, other than a natural person, further
represents: (a) that it is duly organized, existing and in good standing
pursuant to the laws under which it is organized; and (b) that the execution
and delivery of this note and the performance of the obligations it imposes (i)
are within its powers and have been duly authorized by all necessary action of
its governing body; and (ii) do not contravene the terms of its articles of
incorporation or organization, its by laws, or any partnership, operating or
other agreement governing its affairs.

EVENTS OF DEFAULT/ACCELERATION.  If any of the following events occurs, this
note shall be due immediately, without notice, at the Bank's option.

1.   The Borrower or any guarantor of this note ("Guarantor") fails to pay when
     due any amount payable under this note or under any agreement or instrument
     evidencing debt to any creditor;

2.   The Borrower or any Guarantor (a) fails to observe or perform any other
     term of this note; (b) makes any materially incorrect or misleading
     representation, warranty, or certificate to the Bank; (c) makes any
     materially incorrect or misleading representation in any financial
     statement or other information delivered to the Bank; or (d) defaults under
     the terms of any agreement or instrument relating to any debt for borrowed
     money (other than the debt evidenced by this note) such that the creditor
     declares the debt due before its maturity;

3.   There is a default under the terms of any loan agreement, mortgage,
     security agreement, or any other document executed as part of the loan
     evidenced by this note, or any guaranty of the loan evidenced by this note
     becomes unenforceable in whole or in part, or any Guarantor fails to
     promptly perform under its guaranty;

4.   A "reportable event" (as defined in the Employee Retirement Income Security
     Act of 1974 as amended) occurs that would permit the Pension Benefit
     Guaranty Corporation to terminate any employee benefit plan of the Borrower
     or any affiliate of the Borrower;

5.   The Borrower or any Guarantor becomes insolvent or unable to pay its debts
     as they become due;

6.   The Borrower or any Guarantor (a) makes an assignment for the benefit of
     creditors; (b) consents to the appointment of a custodian, receiver, or
     trustee for itself or for a substantial part of its assets; or (c)
     commences any proceeding under any bankruptcy, reorganization, liquidation,
     insolvency or similar laws of any jurisdiction;

7.   A custodian, receiver, or trustee is appointed for the Borrower or any
     Guarantor or for a substantial part of its assets without the consent of
     the party against which the appointment is made and is not removed within
     60 days after such appointment;

8.   Proceedings are commenced against the Borrower or any Guarantor under any
     bankruptcy, reorganization, liquidation, or similar laws of any
     jurisdiction, and such proceedings remain undismissed for 60 days after
     commencement; or the Borrower or Guarantor consents to the commencement of
     such proceedings;

9.   Any judgment is entered against the Borrower or any Guarantor, or any
     attachment, levy, or garnishment is issued against any property of the
     Borrower or any Guarantor;

10.  The Borrower or any Guarantor dies;

11.  The Borrower or any Guarantor, without the Bank's written consent, (a) is
     dissolved, (b) merges or consolidates with any third party, (c) leases,
     sells or otherwise conveys a material part of its assets or business
     outside the ordinary course of business, (d) leases, purchases or otherwise
     acquires a material part of the assets of any other corporation or business
     entity except in the ordinary course of business, or (e) agrees to do any
     of the foregoing (notwithstanding the foregoing, any subsidiary may merge
     or consolidate with any other subsidiary, or with the Borrower so long as
     the Borrower is the survivor);

12.  The loan-to-value ratio of any pledged securities at any time exceeds N/A%,
     and such excess continues for five (5) days after notice from the Bank to
     the Borrower;

13.  There is a substantial change in the existing or prospective financial
     condition of the Borrower or any Guarantor which the Bank in good faith
     determines to be materially adverse;

14.  The Bank in good faith deems itself insecure;


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15.  The acquisition by any Person (as defined below), or two or more Persons
     acting in concert, of beneficial ownership (within the meaning of Rule
     13d-3 of the Securities and Exchange Commission under the Securities
     Exchange Act of 1934) of 20% or more of the outstanding shares of voting
     stock of the Borrower. For purposes of this covenant, "Person" means any
     natural person, corporation, firm, joint venture, partnership, association,
     limited liability company, enterprise, trust or other entity or
     organization, or any government or political subdivision or any agency,
     department of instrumentality thereof.

REMEDIES. If this note is not paid at maturity, whether by acceleration or
otherwise, the Bank shall have all of the rights and remedies provided by any
law or agreement. Any requirement of reasonable notice shall be met if the Bank
sends the notice to the Borrower at least seven (7) days prior to the date of
sale, disposition or other event giving rise to the required notice. The Bank
is authorized to close all or any part of the Collateral to be transferred to
or registered in its name or in the name of any other person, firm or
corporation, with or without designation of the capacity of such nominee. The
Borrower shall be liable for any deficiency remaining after disposition of any
Collateral. The Borrower is liable to the Bank for all reasonable costs and
expenses of every kind incurred in the making or collection of this note,
including, without limitation, reasonable attorneys' fees and court costs.
These costs and expenses shall include, without limitation, any costs or
expenses incurred by the Bank in any bankruptcy, reorganization, insolvency or
other similar proceeding.

WAIVER. Each endorser and any other party liable on this note severally waives
demand, presentment, notice of dishonor and protest, and consents to any
extension or postponement of time of its payment without limit as to the number
or period, to any substitution, exchange or release of all or part of the
Collateral, to the addition of any party, and to the release or discharge of,
or suspension of any rights and remedies against, any person who may be liable
for the payment of this note. No delay on the part of the Bank in the exercise
of any right or remedy shall operate as a waiver. No single or partial exercise
by the Bank of any right or remedy shall preclude any other future exercise of
it or the exercise of any other right or remedy. No waiver or indulgence by the
Bank of any default shall be effective unless in writing and signed by the
Bank, nor shall a waiver on one occasion be construed as a bar to or waiver of
that right on any future occasion.

MISCELLANEOUS. The Borrower, if more than one, shall be jointly and severally
liable, and the term "Borrower" shall mean any one or more of them. This note
shall be binding on the Borrower and its successors, and shall inure to the
benefit of the Bank, its successors and assigns. Any reference to the Bank
shall include any holder of this note. This note is delivered in the State of
Michigan and governed by Michigan law. Section headings are for convenience of
reference only and shall not affect the interpretation of this note.

WAIVER OF JURY TRIAL. The Bank and the Borrower knowingly and voluntarily waive
any right either of them have to a trial by jury in any proceeding (whether
sounding in contract or tort) which is in any way connected with this or any
related agreement, or the relationship established under them. This provision
may only be modified in a written instrument executed by the Bank and the
Borrower.

ADDRESS:                             BORROWER: AMERICAN DENTAL TECHNOLOGIES,INC.

5555 Bear Lane                       By: /s/ BEN J. GALLANT
Corpus Christi, TX 78405                 ---------------------------------------
                                         Ben J. Gallant, President


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