<PAGE>


                             SECURED PROMISSORY NOTE

$1,500,000                                              El Segundo, California
                                                                 June 15, 2000

         FOR VALUE RECEIVED, the undersigned, MICHAEL T. FIORE, (the "BORROWER")
promises to pay to the order of Gentle Dental Management, Inc. a Delaware
corporation (the "COMPANY"), the principal sum of One Million Five Hundred
Thousand Dollars ($1,500,000), with interest from the date hereof on the unpaid
principal at the rate of six point four percent (6.4%), compounded annually. The
entire unpaid balance of principal and interest shall be payable on May 1, 2004.
All amounts payable under this promissory note (this "NOTE") shall be payable in
lawful money of the United States of America. This Note is subject to the
provisions of that certain First Amendment to the Employment Agreement dated
March 11, 1999 by and between InterDent, Inc. ("InterDent") and the Borrower
effective as of May 8, 2000 (the "AMENDMENT"). The performance of borrower's
obligations hereunder are secured by that certain Pledge and Security Agreement
(the "Pledge Agreement") of even date herewith by and between the Company and
Borrower. Any conflict between the provisions of this Promissory Note and the
Amendment will be governed by the terms of the Amendment.

         The principal and accrued interest due under this Note will be with
full recourse to the Borrower only until May 1, 2002 or at such earlier date if
any of the events set forth in Section (6) of the Amendment occur, at which time
the loan and accrued interest will be with recourse only to the Collateral (as
such term is defined in the Pledge Agreement).

         The Borrower at his option may prepay this Note in whole or in part
without penalty at any time or from time to time prior to the due date for full
payment, on ten (10) days' prior written notice to the Company. Any such
prepayments shall be applied first to accrued and unpaid interest and then to
principal on this Note. The Borrower may prepay this Note in cash or through the
exchange of InterDent Common Stock or options to purchase the Common Stock of
InterDent or DentalXChange, Inc. (based on the fair market value of InterDent or
DentalXChange, Inc. Common Stock, which shall equal the average of the market
closing price of the ten (10) most recent trading days prior to the written
notice if either company is publicly traded, or based on the good faith
determination of the InterDent Directors if either company is not publicly
traded; provided, however, that the InterDent Directors shall engage in
discussions with the DentalXChange Board of Directors before making any
determination of the fair market value of DentalXChange, Inc.).

         If Borrower voluntarily terminates his employment relationship with
InterDent, Inc. or is terminated for cause as defined in the Amendment, the
entire unpaid balance of principal and accrued interest under this instrument
shall become due and payable within ten (10) days.

         If payment is not made when due such failure to pay shall constitute an
Event of Default. After an Event of Default, if suit is commenced to collect
this Note or any portion hereof, or to effect the collection of any judgment for
failure to make payment hereunder when and as due, such attorneys' fees and
costs as the court may deem reasonable shall be added to the principal amount of
this Note. The Borrower hereby waives presentment for payment, protest, notice
of protest and notice of non-payment of this Note.

<PAGE>

         This Note shall be governed by, and construed and enforced in
accordance with the laws of the State of California, without regard to conflicts
of laws principles.

         Any provision of this Note may be amended, waived or modified upon the
written consent of each of the Borrower and the Company.

         IN WITNESS WHEREOF, the undersigned has signed, dated and delivered
this note as of the date and year first above written.

                                                            BORROWER:

                                                            /s/ Michael T. Fiore
                                                            --------------------
                                                            Michael T. Fiore

Acknowledged:

GENTLE DENTAL MANAGEMENT, INC.

/s/ Steven Matzkin
----------------------
Steven Matzkin, D.D.S.
President