Exhibit 4.1.6

                         AMENDMENT AGREEMENT NO. 4

                  AMENDMENT AGREEMENT NO. 4 dated as of June 15, 2000 (this
"Agreement"), to the AMENDED AND RESTATED CREDIT AGREEMENT, dated as of June 15,
1999 (as heretofore amended and as may be further amended, modified or
supplemented from time to time the "Credit Agreement"), among GENTLE DENTAL
SERVICE CORPORATION, a Washington corporation ("Dental Service"), GENTLE DENTAL
MANAGEMENT, INC., a Delaware corporation ("Dental Management") and DENTAL CARE
ALLIANCE, INC., a Delaware corporation ("DCA"; DCA, Dental Service and Dental
Management, each a "Borrower" and collectively, the "Borrowers"), the Guarantors
named therein, the financial institutions from time to time party thereto
(collectively, the "Lenders"), UNION BANK OF CALIFORNIA, N.A., as administrative
agent for the Lenders (in such capacity, the "Administrative Agent") and THE
CHASE MANHATTAN BANK ("Chase") , as syndication agent for the Lenders (in such
capacity, the "Syndication Agent").

                  WHEREAS, the Borrowers, the Guarantors and the Lenders desire
to amend certain provisions of the Credit Agreement as set forth herein;

                  NOW, THEREFORE, the Borrowers, the Guarantors, the Lenders,
the Administrative Agent and the Syndication Agent hereby agree as follows:

SECTION 1 CAPITALIZED TERMS. Capitalized terms used herein and not defined shall
have the respective meanings assigned to such terms in the Credit Agreement.

SECTION 2 AMENDMENTS TO THE CREDIT AGREEMENT. Upon the fulfillment of the
conditions set forth in Section 4 hereof the Credit Agreement is hereby amended
as follows:

2.1  Section 1.01 of the Credit Agreement is hereby amended by adding the
     following definitions in the appropriate alphabetical order:

                           "`Senior Subordinated Note' shall mean the Borrowers'
                  Senior Subordinated Note due September 30, 2005 in the
                  original principal amount of $25,500,000, and all instruments
                  or documents related thereto, including, without limitation,
                  the Securities Purchase Agreement referred to therein, in each
                  case as amended, modified or supplemented from time to time in
                  accordance with their respective terms and the limitations set
                  forth in Section 7.17 hereof and the Subordination Agreement.



<PAGE>




                           `Subordination Agreement' shall mean the
                  Subordination Agreement made as of June 15, 2000 among the
                  Administrative Agent, the holder of the Senior Subordinated
                  Note, the Borrowers and Holdings."

2.2      The definition of "Adjusted Total Funded Debt" contained in Section
         1.01 of the Credit Agreement is hereby amended by adding the phrase
         "but shall include the Senior Subordinated Note" at the end of the
         proviso in the first sentence thereof.

2.3  Clause (i)(x) of the definition of "Fixed Charge Coverage Ratio" contain in
     Section 1.01 of the Credit Agreement is hereby amended in its entirety to
     read as follows:

                           "(i) the sum of (x) Funds Flow from Operations of
                           such person for such period plus the unused (treating
                           Letter of Credit usage as usage) availability under
                           the Total Revolving Credit Commitment and the `Total
                           Revolving Credit Commitment' under the 2000 Credit
                           Agreement as of the date of determination less"

2.4      The definition of "Subordinated Indebtedness" contained in Section1.01
         of the Credit Agreement is hereby amended by adding the phrase "and the
         Senior Subordinated Note" immediately following the term "Convertible
         Subordinated Notes" referred to therein.

2.5  Article VII of the Credit Agreement is hereby amended by adding a new
     Section 7.21 at the end thereof to read in its entirety as follows:

                           "Section 7.21. Minimum Annual EBITDA. Permit for each
                  of the Fiscal Years listed in the table below, EBITDA of
                  Holdings and its subsidiaries on a Consolidated basis to be
                  less than the total amount set forth opposite such Fiscal
                  Year:

                           Fiscal Year Ending:         Minimum Annual EBITDA
                           ------------------          ---------------------

                           December 31, 2001                $26,450,000

                           December 31, 2002                 29,900,000

                           December 31, 2003                 33,810,000

                           December 31, 2004                 38,180,000

2.6  The first parenthetical of clause (g) of Article VIII of the Credit
     Agreement is hereby amended in its entirety to read as follows:

<PAGE>




                    "(excluding Indebtedness outstanding hereunder or under the
                           Senior Subordinated Note.)"

2.7  Article VIII of the Credit Agreement is hereby amended by (i) adding an
     "or" at the end of clause (n) thereof and (ii) adding a new clause (o) at
     the end thereof to read as follows:

                                    "(o) default shall be made with respect to
                  any Indebtedness or obligations under the Senior
                  Subordinated Note;"

2.8  Clause (iii) of Section 11.08(b) of the Credit Agreement is hereby amended
     by adding the following parenthetical after the word "Collateral:"

                           "(or grant any other Lien on any of the Collateral)"

SECTION 3 CONFIRMATION OF LOAN DOCUMENTS. Each Loan Party, by its execution and
delivery of this Agreement, irrevocably and unconditionally ratifies and
confirms in favor of the Administrative Agent that it consents to the terms and
conditions of the Credit Agreement as it has been amended by this Agreement and
that notwithstanding this Agreement, each Loan Document to which such Loan Party
is a party shall continue in full force and effect in accordance with its terms,
as it has been amended on the date hereof, and is and shall continue to be
applicable to all of the Obligations.

SECTION 4 CONDITIONS PRECEDENT. This Agreement shall become effective upon the
execution and delivery of counterparts hereof by the Borrowers, the Guarantors,
the Required Lenders and each of the Agents to the Administrative Agent and the
fulfillment of the following conditions:

4.1  All legal matters in connection with this Agreement shall be satisfactory
     to the Agents and their respective counsel in their sole discretion.

4.2      The Administrative Agent shall have received a certificate signed by a
         Financial Officer of each Borrower and Guarantor that (i) both before
         and after giving effect to the transactions contemplated herein all
         representations and warranties contained in this Agreement or otherwise
         made in writing to the Administrative Agent in connection herewith
         shall be true and correct in all material respects on and as of the
         date hereof (except insofar as such representations and warranties
         relate expressly to an earlier date) and (ii) both before and after
         giving effect to the transactions contemplated herein there exists no
         unwaived Default or Event of Default.



<PAGE>



4.3      Messrs. Kaye, Scholer, Fierman, Hays & Handler, LLP and Buchalter,
         Nemer, Fields & Younger, counsel to the Agents, shall have received
         payment in full for all unpaid legal fees charged, and all costs and
         expenses incurred, by such counsel through the date hereof and all
         legal fees charged, and all costs and expenses incurred, by such
         counsel in connection with the transactions contemplated under this
         Agreement and the other Loan Documents and instruments in connection
         herewith and therewith.

4.4  The Administrative Agent shall have received such other documents as the
     Agents or their counsel shall reasonably deem necessary.

SECTION 5         MISCELLANEOUS.
                  --------------

5.1      Each Borrower and each Guarantor reaffirms and restates the
         representations and warranties set forth in Article IV of the Credit
         Agreement, as amended by this Agreement and after giving effect to the
         transactions contemplated herein, and all such representations and
         warranties shall be true and correct in all material respects on and as
         of the date hereof (except insofar as such representations and
         warranties relate expressly to an earlier date). Each Loan Party
         represents and warrants (which representations and warranties shall
         survive the execution and delivery hereof) to the Agent that:

                  (a) It has the corporate power and authority to execute,
         deliver and carry out the terms and provisions of this Agreement and
         the transactions contemplated hereby and has taken or caused to be
         taken all necessary corporate action to authorize the execution,
         delivery and performance of this Agreement and the transactions
         contemplated hereby;

                  (b) No consent of any other person (including, without
         limitation, shareholders or creditors of any Loan Party), and no action
         of, or filing with any governmental or public body or authority is
         required to authorize, or is otherwise required in connection with the
         execution, delivery and performance of this Agreement;

                  (c) This Agreement has been duly executed and delivered on
         behalf of each Loan Party by a duly authorized officer, and constitutes
         a legal, valid and binding obligation of each Loan Party enforceable in
         accordance with its terms, subject to bankruptcy, reorganization,
         insolvency, moratorium and other similar laws affecting the enforcement
         of creditors' rights generally and the exercise of judicial discretion
         in accordance with general principles of equity; and



<PAGE>



                  (d) The execution, delivery and performance of this Agreement
         will not violate any law, statute or regulation, or any order or decree
         of any court or governmental instrumentality, or conflict with, or
         result in the breach of, or constitute a default under any contractual
         obligation of any Loan Party.

5.2      Except, as herein expressly amended, the Credit Agreement is ratified
         and confirmed in all respects and shall remain in full force and effect
         in accordance with its terms.

5.3      All references to the Credit Agreement contained in the Credit
         Agreement and the other Loan Documents and the other documents and
         instruments delivered pursuant to or in connection therewith shall mean
         the Credit Agreement, as amended hereby and as may in the future be
         amended, restated, supplemented or modified from time to time.

5.4      This Agreement may be executed by the parties hereto individually or in
         combination, in one or more counterparts, each of which shall be an
         original and all of which shall constitute one and the same agreement.

5.5      Delivery of an executed counterpart of a signature page to this
         Agreement by telecopier shall be effective as delivery of a
         manually executed counterpart of this Agreement.

5.6      THIS AGREEMENT SHALL BE GOVERNED BY, AND CONSTRUED AND INTERPRETED IN
         ACCORDANCE WITH, THE LAWS OF THE STATE OF CALIFORNIA WITHOUT REGARD TO
         CHOICE OR CONFLICT OF LAW PRINCIPLES THEREOF.

5.7      The parties hereto shall, at any time and from time to time following
         the execution of this Agreement, execute and deliver all such further
         instruments and take all such further actions as may be reasonably
         necessary or appropriate in order to carry out the provisions of this
         Agreement.



<PAGE>



                  IN WITNESS WHEREOF, the Borrowers, Guarantors, the
Administrative Agent, the Syndication Agent and the Required Lenders have caused
this Agreement to be duly executed by their respective authorized officers as of
the day and year first above written.


                                   GENTLE DENTAL SERVICE CORPORATION,
as a Borrower


                                   By:                  MICHAEL THOMAS FIORE
                                                        --------------------
                                            Name:  Michael T. Fiore
                                            Title:     President

                                   GENTLE DENTAL MANAGEMENT, INC.,
                                   as a Borrower


                                   By:                  MICHAEL THOMAS FIORE
                                                        --------------------
                                            Name:  Michael T. Fiore
                                            Title:     President

                                   DENTAL CARE ALLIANCE, INC.,
                                   as a Borrower


                                   By:                 DAVID P. NICHOLS
                                                       ----------------
                                            Name: David P. Nichols
                                            Title:    Chief Financial Officer

                                   GMS HAWAII ACQUISITION COMPANY, as aGuarantor


                                   By:                  MICHAEL THOMAS FIORE
                                                        --------------------
                                            Name:  Michael T. Fiore
                                            Title:     President



<PAGE>



                                   GMS DENTAL GROUP MANAGEMENT OF HAWAII, INC.,
                                      as a Guarantor


                                   By:                  MICHAEL THOMAS FIORE
                                                        --------------------
                                            Name:  Michael T. Fiore
                                            Title:     President

                                   GMS DENTAL GROUP MANAGEMENT OF SOUTHERN
                                      CALIFORNIA, INC., as a Guarantor


                                   By:                  MICHAEL THOMAS FIORE
                                                        --------------------
                                            Name:  Michael T. Fiore
                                            Title:     President


                                   GMS DENTAL GROUP MANAGEMENT OF THE MOUNTAIN
                                       STATES, INC., as a Guarantor


                                   By:                  MICHAEL THOMAS FIORE
                                                        --------------------
                                            Name:  Michael T. Fiore
                                            Title:     President

                                   GENTLE DENTAL MANAGEMENT - PACIFIC NORTHWEST,
                                          INC., as a Guarantor


                                   By:                  MICHAEL THOMAS FIORE
                                                        --------------------
                                            Name:  Michael T. Fiore
                                            Title:     President

                                   GENTLE DENTAL OF IRVINE, as a  Guarantor


                                   By:                  MICHAEL THOMAS FIORE
                                                        --------------------
                                            Name:  Michael T. Fiore
                                            Title:     President



<PAGE>



                                   GDSC OF PIEDMONT, INC., as a Guarantor


                                   By:                  MICHAEL THOMAS FIORE
                                                        --------------------
                                            Name:  Michael T. Fiore
                                            Title:     President


                                   GENTLE DENTAL LEGACY, INC.,
                                   as a Guarantor


                                   By:                  MICHAEL THOMAS FIORE
                                                        --------------------
                                            Name:  Michael T. Fiore
                                            Title:     President


                                   DENTAL CARE ALLIANCE OF FLORIDA, INC., as a
                                     Guarantor


                                   By:                 DAVID P. NICHOLS
                                                       ----------------
                                            Name: David P. Nichols
                                            Title:     Chief Financial Officer


                                   DENTAL CARE ALLIANCE OF MICHIGAN, INC., as a
                                       Guarantor


                                   By:                 DAVID P. NICHOLS
                                                       ----------------
                                            Name: David P. Nichols
                                            Title:     Chief Financial Officer

                                   DENTAL CARE ALLIANCE OF GEORGIA, INC., as a
                                     Guarantor


                                   By:                 DAVID P. NICHOLS
                                                       ----------------
                                            Name: David P. Nichols
                                            Title:     Chief Financial Officer



<PAGE>



                                   DENTAL CARE ALLIANCE OF INDIANA, INC.,
                                       as a Guarantor


                                   By:                 DAVID P. NICHOLS
                                                       ----------------
                                            Name: David P. Nichols
                                            Title:     Chief Financial Officer

                                   DENTAL ONE ASSOCIATES, INC., as a Guarantor


                                   By:                 DAVID P. NICHOLS
                                                       ----------------
                                            Name: David P. Nichols
                                            Title:     Chief Financial Officer

                                   DENTAL CARE ALLIANCE OF PENNSYLVANIA, INC.,
                                     as a Guarantor


                                   By:                 DAVID P. NICHOLS
                                                       ----------------
                                            Name: David P. Nichols
                                            Title:     Chief Financial Officer

                                   SERRA PARK DENTAL SERVICES, INCORPORATED,
                                     as a Guarantor


                                   By:                  MICHAEL THOMAS FIORE
                                                        --------------------
                                            Name:  Michael T. Fiore
                                            Title:     President

                                   SPDS DMI, INCORPORATED, as a Guarantor


                                   By:                  MICHAEL THOMAS FIORE
                                                        --------------------
                                            Name:  Michael T. Fiore
                                            Title:     President



<PAGE>



                                   UNION BANK OF CALIFORNIA, N.A., as
                                      Administrative Agent and as a Lender


                                   By:                 NANCY PERKINS
                                                       -------------
                                            Name: Nancy A. Perkins
                                            Title:    Vice President


                                   THE CHASE MANHATTAN BANK, as Syndication
                                       Agent and as a Lender


                                   By:                 CAROL EDKINS
                                                       ------------
                                            Name: Carol A. Edkins
                                            Title:    Vice President

                                   U.S. BANK NATIONAL ASSOCIATION, as a Lender


                                   By:                 MARK OLAN
                                                       ---------
                                            Name: Mark. R. Olan
                                            Title:    Sr. Vice President

                                   FLEET CAPITAL CORPORATION, as a Lender


                                   By:
                                      ----------------------------------
                                            Name:
                                            Title:

                                   BANK OF AMERICA, N.A. (successor by merger
                                     to NationsBank, N. A.), as a Lender


                                   By:__________________________________
                                            Name:
                                            Title:



<PAGE>



                                   FIRST NATIONAL BANK, as a Lender


                                   By:                 DAVID S. WALTERS
                                                       ----------------
                                            Name: David S. Walters
                                            Title:    Vice President

                                   CITIZENS BANK OF MASSACHUSETTS,
                                   as a Lender


                                   By:                 MICHAEL OVELLET
                                                       ---------------
                                            Name: Michael Ovellet
                                            Title:    Asst. Vice President

                                   SOVEREIGN BANK, as a Lender


                                   By:                 J BECKER
                                                       --------
                                            Name: J Becker
                                            Title:    Sr. Vice President



Solely as to Sections 3 and 5:   INTERDENT, INC., as a Guarantor


                                   By:                  MICHAEL THOMAS FIORE
                                                        --------------------
                                            Name:  Michael T. Fiore
                                            Title:     President