REGISTRATION RIGHTS AGREEMENT

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Exhibit 4.2

REGISTRATION RIGHTS AGREEMENT
  
by and among
   
IDI ACQUISITION CORP.,
   
INTERDENT SERVICE CORPORATION,
   
INTERDENT, INC.
   
and
   
JEFFERIES & COMPANY, INC.

  
Dated as of December 15, 2004

        This Registration Rights Agreement, dated as of December 15, 2004 (this " Agreement "), is entered into by and among (i) IDI Acquisition Corp., a Delaware corporation (the " Company "), and InterDent Service Corporation, a Washington corporation (" Service " and together with the Company, the " Issuers "), (ii) InterDent, Inc., a Delaware corporation, the owner of all of the capital stock of Service (" Parent "), and (iii) Jefferies & Company, Inc. (the " Initial Purchaser "), which has agreed to purchase the Issuers' 10 ³ / 4 % Senior Secured Notes due 2011 (the " Series A Notes ") pursuant to the Purchase Agreement. Substantially concurrent with the issuance of the Series A Notes, the Company will be merged with and into Service (the " Merger ") pursuant to an Agreement and Plan of Merger, between the Company, Service and Parent (the " Merger Agreement "). Service will survive the Merger and upon the filing of the appropriate Merger documents with the Delaware Secretary of State and Washington Secretary of State, will assume all of the obligations of the Company under the Indenture, the Notes and this Agreement.

        This Agreement is made pursuant to the Purchase Agreement, dated as of December 10, 2004 (the " Purchase Agreement "), by and among the Issuers, Parent and the Initial Purchaser. In order to induce the Initial Purchaser to purchase the Series A Notes, the Issuers and Parent have agreed to provide, subject to the conditions in this Agreement, the registration rights set forth in this Agreement. The execution and delivery of this Agreement is a condition to the obligations of the Initial Purchaser set forth in Section 9 of the Purchase Agreement. Capitalized terms used herein and not otherwise defined shall have the meaning assigned to them in the Indenture, dated December 15, 2004 (the " Indenture "), among the Issuers, Parent and Wells Fargo Bank, National Association, as Trustee, relating to the Series A Notes and the Series B Notes (defined below).

        The parties hereby agree as follows:

SECTION 1. DEFINITIONS

        As used in this Agreement, the following capitalized terms shall have the following meanings:

        " Act " means the Securities Act of 1933, as amended, and the rules and regulations of the SEC promulgated thereunder.

        " Affiliate " has the meaning set forth in Rule 144 of the Act.

        " Agreement " has the meaning set forth in the preamble of this Agreement.

        " Broker-Dealer " means any broker or dealer registered under the Exchange Act.

        " Business Day " means any day except a Saturday, Sunday or any other day on which banking institutions in the City of New York, or in the city of the corporate trust office of the Trustee, are authorized or obligated by law or regulation to close.

        " Closing Date " means the date of this Agreement.

        " Company " has the meaning set forth in the preamble.

        " Consummate " means, and an Exchange Offer shall be deemed Consummated for purposes of this Agreement upon, the occurrence of (a) the filing and effectiveness under the Act of the Exchange Offer Registration Statement relating to the Series B Notes to be issued in the Exchange Offer, (b) the maintenance of such Exchange Offer Registration Statement continuously effective and the keeping of the Exchange Offer open for a period not less than the period required pursuant to Section 3(b) and (c) the delivery by the Issuers to the Registrar under the Indenture of Series B Notes in the same aggregate principal amount as the aggregate principal amount of Series A Notes tendered by Holders thereof pursuant to the Exchange Offer.

        " Consummation Deadline " has the meaning set forth in Section 3(a).

        " Exchange Act " means the Securities Exchange Act of 1934, as amended, and the rules and regulations of the SEC promulgated thereunder.

        " Exchange Effectiveness Deadline " has the meaning set forth in Section 3(a).

        " Exchange Filing Deadline " has the meaning set forth in Section 3(a).

        " Exchange Offer " means the exchange and issuance by the Issuers of a principal amount of Series B Notes (which shall be registered pursuant to the Exchange Offer Registration Statement) equal to the outstanding principal amount of Series A Notes that are validly tendered by such Holders in connection with such exchange and issuance.

        " Exchange Offer Registration Statement " means the Registration Statement relating to the Exchange Offer, including the related Prospectus.

        " Guarantors " means Parent and each future subsidiary of the Company, if any, that is required by the terms of the Indenture to guarantee the Series A Notes and/or Series B Notes.

        " Holders " shall have the meaning set forth in Section 2.

        " Indemnified Party " has the meaning set forth in Section 8(c).

        " Indemnifying Party " has the meaning set forth in Section 8(c).

        " Indenture " has the meaning set forth in the preamble of this Agreement.

        " Initial Purchaser " has the meaning set forth in the preamble of this Agreement.

        " Issuers " has the meaning set forth in the preamble of this Agreement.

        " Parent " has the meaning set forth in the preamble of this Agreement.

        " Person " means any individual, corporation, partnership, joint venture, association, joint stock company, trust, unincorporated organization, limited liability company or government or other entity.

        " Prospectus " means the prospectus included in a Registration Statement at the time such Registration Statement is declared effective (including without limitation, a prospectus that discloses information previously omitted from a prospectus filed as part of an effective Registration Statement in reliance on Rule 430A under the Act), as amended or supplemented by any prospectus supplement and by all other amendments thereto, including post-effective amendments, and all material incorporated by reference into such Prospectus.

        " Purchase Agreement " has the meaning set forth in the preamble of this Agreement.

        " Recommencement Date " has the meaning set forth in Section 6(d).

        " Registration Default " has the meaning set forth in Section 5.

        " Registration Statement " means any registration statement of the Issuers and the Guarantors relating to (a) an offering of Series B Notes pursuant to an Exchange Offer or (b) the registration for resale of Transfer Restricted Securities pursuant to the Shelf Registration Statement, in each case, (i) that is filed pursuant to the provisions of this Agreement and (ii) including the Prospectus included therein, all amendments and supplements thereto (including post-effective amendments) and all exhibits and materials incorporated by reference therein.

        " Rule 144 " means Rule 144 promulgated under the Act.

        " SEC " shall mean the Securities and Exchange Commission.

        " Series A Notes " has the meaning set forth in the preamble of this Agreement.

        " Series B Notes " means the Issuers' 10 ³ / 4 % Series B Senior Secured Notes due 2011 to be issued pursuant to the Indenture (a) in the Exchange Offer or (b) as contemplated by Section 4.

        " Shelf Effectiveness Deadline " has the meaning set forth in Section 4(a).

        " Shelf Filing Deadline " has the meaning set forth in Section 4(a).

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        " Shelf Registration Statement " has the meaning set forth in Section 4(a).

        " Suspension Notice " has the meaning set forth in Section 6(d).

        " TIA " means the Trust Indenture Act of 1939 as in effect on the date of the Indenture.

        " Transfer Restricted Securities " means each Series A Note until (i) the date on which such Series A Note has been exchanged by a Person other than a Broker-Dealer for a Series B Note in the Exchange Offer; (ii) following the exchange by a Broker-Dealer in the Exchange Offer of a Series A Note for a Series B Note, the date on which the Series B Note is sold or otherwise disposed of to a purchaser who receives from such Broker-Dealer on or prior to the date of such sale a copy of the prospectus contained in the Exchange Offer Registration Statement; (iii) the date on which such note has been registered under the Act and disposed of in accordance with the Shelf Registration Statement; or (iv) the date on which such note is distributed to the public pursuant to Rule 144.

SECTION 2. HOLDERS

        A Person is deemed to be a holder of Transfer Restricted Securities (each, a " Holder ") whenever such Person owns Transfer Restricted Securities.

SECTION 3. REGISTERED EXCHANGE OFFER

        (a)   Unless the Exchange Offer shall not be permitted by applicable law or SEC policy, the Issuers and the Guarantors shall (i) cause the Exchange Offer Registration Statement to be filed with the SEC not later than 120 days after the Closing Date (such 120th day being the " Exchange Filing Deadline "), (ii) use commercially reasonable efforts to cause such Exchange Offer Registration Statement to be declared effective by the SEC on or prior to 210 days after the Closing Date (such 210th day being the " Exchange Effectiveness Deadline "), and (iii) commence the Exchange Offer promptly following the declaration of effectiveness of such Exchange Offer Registration Statement and Consummate the Exchange Offer on or prior to the date 30 Business Days after the Exchange Offer Registration Statement is declared effective (such 30th day being the " Consummation Deadline "). The Exchange Offer shall be on the appropriate form permitting (x) registration of the Series B Notes to be offered in exchange for the Series A Notes that are Transfer Restricted Securities and (y) resales of Series B Notes by Broker-Dealers that tendered into the Exchange Offer Series A Notes that such Broker-Dealer acquired for its own account as a result of market-making activities or other trading activities (other than Series A Notes acquired directly from the Issuers or any of their Affiliates) as contemplated by Section 3(c).

        (b)   The Issuers and the Guarantors shall use their respective commercially reasonable efforts to cause the Exchange Offer Registration Statement to be effective continuously, and shall keep the Exchange Offer open for a period of not less than the minimum period required under applicable securities laws to Consummate the Exchange Offer; provided, however, that in no event shall such period be less than 20 Business Days. The Issuers and the Guarantors shall cause the Exchange Offer to comply with all applicable securities laws. No securities other than the Series B Notes shall be included in the Exchange Offer Registration Statement.

        (c)   The Issuers and the Guarantors shall include a " Plan of Distribution " section in the Prospectus contained in the Exchange Offer Registration Statement and indicate therein that any Broker-Dealer who holds Transfer Restricted Securities that were acquired for the account of such Broker-Dealer as a result of market-making activities or other trading activities (other than Series A Notes acquired directly from the Issuers or any of their Affiliate), may exchange such Transfer Restricted Securities pursuant to the Exchange Offer. Such " Plan of Distribution " section shall also contain all other information with respect to such sales by such Broker-Dealers that the SEC may require in order to permit such sales pursuant thereto, but such " Plan of Distribution " shall not name any such Broker-

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Dealer or disclose the amount of Transfer Restricted Securities held by any such Broker-Dealer, except to the extent required by the SEC as a result of a change in policy, rules or regulations after the date of this Agreement.

        Because any such Broker-Dealer may be deemed to be an " underwriter " within the meaning of the Act and must, therefore, deliver a prospectus meeting the requirements of the Act in connection with the initial sale of any Series B Notes received by such Broker-Dealer in the Exchange Offer, the Issuers and the Guarantors shall permit the use of the Prospectus contained in the Exchange Offer Registration Statement by such Broker-Dealer to satisfy such prospectus delivery requirement. To the extent necessary to ensure that the Prospectus contained in the Exchange Offer Registration Statement is available for sales of Series B Notes by Broker-Dealers, the Issuers and the Guarantors agree to use their respective commercially reasonable efforts to keep the Exchange Offer Registration Statement continuously effective, supplemented, amended and current as required by and subject to the provisions of Section 6(a) and (c) and in conformity with the requirements of this Agreement, the Act and the policies, rules and regulations of the SEC as announced from time to time, for a period of 180 days from the Consummation Deadline or such shorter period as will terminate when all Transfer Restricted Securities covered by such Registration Statement have been sold pursuant thereto. The Issuers and the Guarantors shall provide sufficient copies of the latest version of such Prospectus to such Broker-Dealers, promptly upon request, and in no event later than one day after such request, at any time during such period.

SECTION 4. SHELF REGISTRATION

        (a)    Shelf Registration . If, (i) the Exchange Offer is not permitted by applicable law or SEC policy (after the Issuers and the Guarantors have complied with the procedures set forth in Section 6(a)(iii)(A)) or (ii) any Holder notifies the Issuers prior to the 20th Business Day following the Consummation Deadline that (A) it is prohibited by law or SEC policy from participating in the Exchange Offer; or (B) it may not resell the Series B Notes acquired by it in the Exchange Offer to the public without delivering a prospectus and the Prospectus contained in the Exchange Offer Registration Statement is not appropriate or available for such resales by such Holder; or (C) it is a Broker-Dealer and holds Series A Notes acquired directly from the Issuers or any of their Affiliates, then the Issuers and the Guarantors will:

        (x)   use their respective commercially reasonable efforts, to cause to be filed, on or prior to 30 days after the earlier of (i) the date on which the Issuers determine that the Exchange Offer Registration Statement cannot be filed as a result of clause (a)(i) of this Section 4 and (ii) the date on which the Issuers receive the notice specified in clause (a)(ii) of this Section 4, (such earlier date, the " Shelf Filing Deadline "), a shelf registration statement for an offering to be made on a continuous basis pursuant to Rule 415 under the Act (which may be an amendment to the Exchange Offer Registration Statement (the " Shelf Registration Statement ")), relating to all Transfer Restricted Securities provided, however , that notwithstanding this Section 4(a)(x), the Issuers and the Guarantors shall not be required to file the Shelf Registration Statement prior to Exchange Offer Filing Deadline; and

        (y)   use their respective commercially reasonable efforts to cause such Shelf Registration Statement to become effective on or prior to 90 days after the earlier of (i) the date on which the Issuers determine that the Exchange Offer Registration Statement cannot be filed as a result of clause (a)(i) of this Section 4 and (ii) the date on which the Issuers receive the notice specified in clause (a)(ii) of this Section 4, (such 90th day the " Shelf Effectiveness Deadline ").

        If, after the Issuers have filed an Exchange Offer Registration Statement that satisfies the requirements of Section 3(a), the Issuers are required to file and make effective a Shelf Registration Statement solely because the Exchange Offer is not permitted under applicable law (i.e.,

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clause (a)(ii) of this Section 4), then the filing of the Exchange Offer Registration Statement shall be deemed to satisfy the requirements of clause (x) of this Section 4(a); provided , that in such event, the Issuers shall remain obligated to meet the Shelf Effectiveness Deadline set forth in clause (y) of this Section 4(a).

        To the extent necessary to ensure that the Shelf Registration Statement is available for sales of Transfer Restricted Securities by the Holders thereof entitled to the benefit of this Section 4(a) and the other securities required to be registered therein pursuant to Section 6(b)(ii), the Issuers and the Guarantors shall use their respective commercially reasonable efforts to keep any Shelf Registration Statement required by this Section 4(a) continuously effective, supplemented, amended and current as required by and subject to the provisions of Sections 6(b) and (c) and in conformity with the requirements of this Agreement, the Act and the policies, rules and regulations of the SEC as announced from time to time, for a period of at least two years (as extended pursuant to Section 6(d) following the Closing Date, or such shorter period as will terminate when all Transfer Restricted Securities covered by such Shelf Registration Statement have been sold pursuant thereto.

        (b)    Provision by Holders of Certain Information in Connection with the Shelf Registration Statement .    No Holder may include any of its Transfer Restricted Securities in any Shelf Registration Statement pursuant to this Agreement unless and until such Holder furnishes to the Issuers in writing, within 10 days after receipt of a request therefor, the information specified in Item 507 or 508 of Regulation S-K, as applicable, of the Act for use in connection with any Shelf Registration Statement or Prospectus or preliminary Prospectus included therein. No Holder shall be entitled to liquidated damages pursuant to Section 5 unless and until such Holder shall have provided all such information. Each selling Holder agrees to promptly furnish additional information as requested by the SEC or as required to be disclosed in order to make the information previously furnished to the Issuers by such Holder not materially misleading.

SECTION 5. LIQUIDATED DAMAGES

        If (a) any Registration Statement required by this Agreement is not filed with the SEC on or prior to the applicable Exchange Offer Filing Deadline or Shelf Filing Deadline, (b) any such Registration Statement has not been declared effective by the SEC on or prior to the applicable Exchange Effectiveness Deadline or Shelf Effectiveness Deadline, (c) the Exchange Offer has not been Consummated on or prior to the Consummation Deadline or (d) the Shelf Registration Statement or the Exchange Offer Registration Statement is filed and declared effective but thereafter ceases to be effective or usable in connection with resales of Transfer Restricted Securities during the periods specified in this Agreement (each such event referred to in clauses (a) through (d) above, a " Registration Default "), then the Issuers and the Guarantors hereby jointly and severally agree to pay to each Holder of Transfer Restricted Securities affected thereby liquidated damages at a rate equal to 0.25% per annum on the outstanding principal amount of Transfer Restricted Securities held by such Holder with respect to the first 90-day period immediately following the occurrence of the first Registration Default. The amount of the liquidated damages shall increase at a rate of 0.25% per annum on the outstanding principal amount of Transfer Restricted Securities held by such Holder with respect to each subsequent 90-day period until all Registration Defaults have been cured, up to a maximum rate of liquidated damages of 1.00% per annum of the outstanding principal amount of Transfer Restricted Securities held by such Holder; provided , that the Issuers and the Guarantors shall in no event be required to pay liquidated damages for more than one Registration Default at any given time. Notwithstanding anything to the contrary set forth herein, (i) upon filing of the Exchange Offer Registration Statement (and/or, if applicable, the Shelf Registration Statement), in the case of clause (a) of this Section 5, (ii) upon the effectiveness of the Exchange Offer Registration Statement (and/or, if applicable, the Shelf Registration Statement), in the case of clause (b) of this Section 5, (iii) upon Consummation of the Exchange Offer, in the case of clause (c) of this Section 5, or

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(iv) upon the filing of a post-effective amendment to the Registration Statement or an additional Registration Statement that causes the Exchange Offer Registration Statement (and/or, if applicable, the Shelf Registration Statement) to again be declared effective or made usable in the case of clause (d) of this Section 5, the liquidated damages payable with respect to the Transfer Restricted Securities as a result of such clauses (a), (b), (c) or (d) of this Section 5, as applicable, shall cease.

        All accrued liquidated damages will be paid by the Issuers and the Guarantors to the Holders entitled thereto, in the manner provided for the payment of interest in the Indenture, on the next scheduled Interest Payment Date (as such date is defined in the Indenture), as more fully set forth in the Indenture and the Notes. Notwithstanding the fact that any Notes for which liquidated damages are due cease to be Transfer Restricted Securities, all obligations of the Issuers and the Guarantors to pay such accrued liquidated damages with respect to securities shall survive until such time as such obligations with respect to the Notes have been satisfied in full. The liquidated damages set forth above shall be the exclusive monetary remedy available to the Holders for a Registration Default.

SECTION 6. REGISTRATION PROCEDURES

        (a)    Exchange Offer Registration Statement .    In connection with the Exchange Offer, the Issuers and the Guarantors shall (i) comply with all applicable provisions of Section 6(c), (ii) use their respective commercially reasonable efforts to effect such exchange and to permit the resale of Series B Notes by Broker-Dealers that tendered in the Exchange Offer Series A Notes that such Broker-Dealer acquired for its own account as a result of its market-making activities or other trading activities (other than Series A Notes acquired directly from the Issuers or any of their Affiliates) being sold in accordance with the intended method or methods of distribution thereof, and (iii) comply with all of the following provisions:

        (A)  If, following the date hereof there has been announced a change in SEC policy with respect to exchange offers such as the Exchange Offer, that in the reasonable opinion of counsel to the Issuers raises a substantial question as to whether the Exchange Offer is permitted by applicable law, the Issuers and the Guarantors hereby agree to seek a no-action letter or other favorable decision from the SEC allowing the Issuers and the Guarantors to Consummate an Exchange Offer for such Transfer Restricted Securities. The Issuers and the Guarantors hereby agree to pursue the issuance of such a decision to the SEC staff level. In connection with the foregoing, the Issuers and the Guarantors hereby agree to take all such other commercially reasonable actions as may be requested by the SEC or otherwise required in connection with the issuance of such decision, including without limitation (1) participating in telephonic conferences with the SEC, (2) delivering to the SEC staff an analysis prepared by counsel to the Issuers setting forth the legal basis, if any, upon which such counsel has concluded that such an Exchange Offer should be permitted and (3) diligently pursuing a resolution (which need not be favorable) by the SEC staff.

        (B)  As a condition to its participation in the Exchange Offer, each Holder of Transfer Restricted Securities (including, without limitation, any Holder who is a Broker-Dealer) shall furnish, if requested by the Issuers, prior to the Consummation of the Exchange Offer, a written representation to the Issuers and the Guarantors (which shall be contained in the letter of transmittal contemplated by the Exchange Offer Registration Statement or be deemed made by virtue of tendering into the Exchange Offer pursuant to the provisions of the Exchange Offer Prospectus) to the effect that (1) it is not an Affiliate of the Issuers, (2) it is not engaged in, and does not intend to engage in, and has no arrangement or understanding with any Person to participate in, a distribution of the Series B Notes to be issued in the Exchange Offer and (3) it is acquiring the Series B Notes in its ordinary course of business. As a condition to its participation in the Exchange Offer, each Holder using the Exchange Offer to participate in a distribution of the Series B Notes shall acknowledge and agree that, if the resales are of Series B Notes obtained

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by such Holder in exchange for Series A Notes acquired directly from the Issuers or an Affiliate thereof, it (x) could not, under SEC policy as in effect on the date of this Agreement, rely on the position of the SEC enunciated in Morgan Stanley and Co., Inc. (available June 5, 1991) and Exxon Capital Holdings Corporation (available May 13, 1988), as interpreted in the SEC's letter to Shearman & Sterling dated July 2, 1993, and similar no-action letters (including, if applicable, any no-action letter obtained pursuant to clause (a)(iii)(A) of this Section 6), and (y) must comply with the registration and prospectus delivery requirements of the Act in connection with a secondary resale transaction and that such a secondary resale transaction must be covered by an effective registration statement containing the selling security holder information required by Item 507 or 508, as applicable, of Regulation S-K.

        (C)  To the extent required by SEC policies and procedures, prior to effectiveness of the Exchange Offer Registration Statement, the Issuers and the Guarantors shall provide a supplemental letter to the SEC (1) stating that the Issuers and the Guarantors are registering the Exchange Offer in reliance on the position of the SEC enunciated in Exxon Capital Holdings Corporation (available May 13, 1988), Morgan Stanley and Co., Inc. (available June 5, 1991) as interpreted in the SEC's letter to Shearman & Sterling dated July 2, 1993, and, if applicable, any no-action letter obtained pursuant to clause (a)(iii)(A) of this Section 6, (2) including a representation that neither any Issuer nor any Guarantor has entered into any arrangement or understanding with any Person to distribute the Series B Notes to be received in the Exchange Offer and that, to the best of the Issuers' and each Guarantor's information and belief, each Holder participating in the Exchange Offer is acquiring the Series B Notes in its ordinary course of business and has no arrangement or understanding with any Person to participate in the distribution of the Series B Notes received in the Exchange Offer and (3) any other undertaking or representation required by the SEC as set forth in any no-action letter obtained pursuant to clause (a)(iii)(A) of this Section 6, if applicable.

        (b)    Shelf Registration Statement .    In connection with the Shelf Registration Statement, the Issuers and the Guarantors shall:

        (i)    comply with all the provisions of Section 6(c) and use their respective commercially reasonable efforts to effect such registration to permit the sale of the Transfer Restricted Securities being sold in accordance with the intended method or methods of distribution thereof (as indicated in the information furnished to the Issuers pursuant to Section 4(b)), and pursuant thereto the Issuers and the Guarantors shall prepare and file with the SEC a Registration Statement relating to the registration on any appropriate form under the Act, which form shall be available for the sale of the Transfer Restricted Securities in accordance with the intended method or methods of distribution thereof within the time periods and otherwise in accordance with the provisions hereof; and

        (ii)   issue, upon the request of any Holder or purchaser of Series A Notes covered by any Shelf Registration Statement contemplated by this Agreement, Series B Notes having an aggregate principal amount equal to the aggregate principal amount of Series A Notes sold pursuant to the Shelf Registration Statement and surrendered to the Issuers for cancellation; the Issuers shall register the Series B Notes on the Shelf Registration Statement for this purpose and issue the Series B Notes to the purchaser(s) of securities subject to the Shelf Registration Statement in the names as such purchaser(s) shall designate.

        (c)    General Provisions .    In connection with any Registration Statement that the Issuers and the Guarantors elect to file pursuant to Section 3 or are required to file pursuant to Section 4 and any related Prospectus, the Issuers and the Guarantors shall:

        (i)    use their respective commercially reasonable efforts to keep such Registration Statement continuously effective and provide all requisite financial statements for the period specified in

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Sections 3 or 4 of this Agreement, as applicable. Upon the occurrence of any event that would cause any such Registration Statement or the Prospectus contained therein (A) to contain an untrue statement of material fact or omit to state any material fact necessary to make the statements therein not misleading or (B) not to be effective and usable for resale of Transfer Restricted Securities during the period required by this Agreement, the Issuers and the Guarantors shall file promptly an appropriate amendment to such Registration Statement o