AMERICAN DENTAL PARTNERS, INC. 2005 EQUITY INCENTIVE PLAN NONQUALIFIED STOCK OPTION AGREEMENT

Exhibit 10.1

AMERICAN DENTAL PARTNERS, INC.

2005 EQUITY INCENTIVE PLAN

NONQUALIFIED STOCK OPTION AGREEMENT

American Dental Partners, Inc., a Delaware corporation (the “Company”), has granted to                      (the “Participant”) an option (the “Option”) to purchase              shares of the Company’s common stock, $.01 par value (the “Shares”), for a purchase price of $             per Share (the “Option Price”). The Option has been granted pursuant to the American Dental Partners, Inc. 2005 Equity Incentive Plan, as amended (the “Plan”), and shall include and be subject to all provisions of the Plan, which are hereby incorporated herein by reference. The Option shall also be subject to the following provisions of this agreement:

§1. Vesting. The Option shall be exercisable only with respect to the Shares which have become “vested” from time to time under this agreement. The Option shall vest with respect to 25% of the Shares subject to the Option on each of the first four anniversaries of the date the Option is granted, as set forth at the end of this agreement (the “Grant Date”), so that the Option shall become vested with respect to the following percentages of the total number of Shares subject to the Option (computed cumulatively and rounded to the nearest whole number of Shares) on the following anniversaries of the Grant Date, respectively, subject to the Participant’s continuous status as an employee of the Company or any of its subsidiaries on such dates:

§2. Term. The Option shall expire on tenth anniversary of the Grant Date to the extent not previously exercised but shall be subject to earlier termination as provided in Sections 6 and 13 of the Plan. Except as provided in §3, below, upon termination of the Participant’s employment by the Company and all of its subsidiaries, any portion of the Option which has not become vested as of the date of such termination shall terminate automatically as of such date.

§3. Qualified Retirement. Notwithstanding any other provisions of this agreement or the Plan to the contrary, if the Participant’s employment with the Company and its subsidiaries terminates by reason of a Qualified Retirement (as defined below), then: (a) the Option shall continue to vest on the schedule provided in this agreement and Plan until the earlier of the third anniversary of the date of such Qualified Retirement or the tenth anniversary of the Grant Date (the “Post-Retirement Period”); and (b) the Participant shall have the right to exercise the Option with respect to any portion of the Option that is vested as of the date of such Qualified Retirement, or becomes vested during the Post-Retirement Period, until the end of the Post-Retirement Period; provided that (i) the Participant’s right to exercise the Option shall be subject to all other restrictions and requirements contained in this agreement of the Plan, and (ii) the Option shall terminate automatically, and Participant’s right to exercise the Option shall terminate automatically, if Participant violates any of the provisions of §4 of this agreement.

For purposes of this agreement, the term “Qualified Retirement” shall mean the Participant’s termination of employment with or service to the Company and its subsidiaries (other than by reason of death, disability, or termination by the Company or any of its subsidiaries for cause) if at the time of such termination, Participant’s age is at least 60 and the Participant has at least five years of continuous service with the Company or any of its subsidiaries.

§4. Confidentiality; Noncompetition. The Participant shall not, directly or indirectly, at any time, disclose any Confidential Information (defined below) to any person (other than the Company or its subsidiaries), or use, or assist any person (other than the Company or its subsidiaries) to use, any Confidential Information, excepting only disclosures required by applicable law. In addition, during the Post-Retirement Period, the Participant shall not, directly or indirectly (whether individually or as a shareholder or other owner, partner, member, director, officer, employee, consultant, creditor, or agent of any person, association, or other entity):

(a) Enter into, engage in, or promote or assist (financially or otherwise), directly or indirectly, any business that provides management, consulting, or other services of the type provided by the Company or any of its subsidiaries (hereinafter for purposes of this section, simply the “Company”) in any state in which the Company provides such services;

(b) Induce or encourage any employee, officer, director, agent, supplier, or independent contractor of the Company, to terminate its relationship with the Company, or otherwise interfere or attempt to interfere in any way with the Company’s relationships with its employees, officers, directors, agents, suppliers, independent contractors, patients, or others;

(c) Employ or engage any person who, at any time within the one-year period immediately preceding his or her employment or engagement, was an employee, officer, director, or agent of the Company; or

(d) Make any statement (oral or written) which disparages the reputation of the Company or any Affiliated Company.

For purposes of this §4, the term “Confidential Information” shall mean all trade secrets, proprietary data and other confidential information of Company, including without limitation financial information; information relating to business operations; services; promotional practices; computer software; system/organizational manuals and related documents; professional group organizational manuals and related documents; protocols; guidelines; patient record forms, training, education and service program systems, documents and presentations; quality assurance systems, manuals and programs; privileging, credentialing, grievance, peer review and quality improvement manuals and related documents; prepaid dental programs; and relationships with suppliers, employees, independent contractors, patients or others, and any information that the Company is obligated to treat as confidential by law or pursuant to any course of dealing or any agreement to or by which it is a party or otherwise bound; provided that Confidential Information shall not include any information that is generally available to the public and did not become so as a result of any breach of this agreement by the Participant.

The Participant hereby (i) acknowledges and agrees that the provisions of this §4 are fundamental and essential for the protection of the Company legitimate business and proprietary interests, the provisions are reasonable and appropriate in all respects, and the Company’s remedies at law for any violation or attempted violation by the Participant of any of its obligations under this §4 would be inadequate, and (ii) agrees that in the event of any such violation or attempted violation, the Company shall be entitled to a temporary restraining order, temporary and permanent injunctions, specific performance and other equitable relief, without the necessity of posting any bond or proving any actual damage, in addition to all other rights and remedies that may be available to the Company from time to time.

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§5. Method of Exercise. At any time when the Option is exercisable under the Plan and this agreement, and subject to any applicable restrictions on exercise of the Option under the Plan or this agreement, the Option shall be exercisable, in whole or in part, from time to time during the term of the Option by written notice to the Company at its principal office, which notice shall:

(a) State that the Option is being exercised thereby and specify the number of Shares (which must be a whole number) with respect to which the Option is being exercised, the name of each person in whose name any such Shares should be registered, his address, and his social security number;

(b) Be signed by the person or persons entitled to exercise the Option and, if the Option is being exercised by anyone other than the Participant, be accompanied by proof satisfactory to counsel for the Company of the right of such person or persons to exercise the Option under the Plan and all applicable laws and regulations; and

(c) Contain representations, warranties, and agreements with respect to the investment intention of such person or persons in form and substance satisfactory to counsel for the Company.

§6. Notice of Disposition. The person exercising the Option shall notify the Company when making any disposition of the Shares acquired upon exercise of the Option, whether by sale, gift or otherwise.

§7. Payment of Price. Upon exercise of the Option with respect to any of the Shares and payment of the purchase price and any applicable withholding taxes for such Shares in a manner permissible under the Plan, the Company shall issue the Shares to the specified person or persons as provided in the Plan.

§8. Transferability. The Option shall not be transferable by the Participant except as provided in the Plan. Unless transferred as provided in the Plan, the Option shall be exercisable during the lifetime of the Participant (subject to any other applicable restrictions on exercise) only by the Participant (or his legal representative) for his own account.

§9. Restrictions. The Option and any Shares issued upon exercise of the Option shall be subject to all restrictions in this agreement or in the Plan. As a condition of any exercise of the Option, the Company may require the Participant or his successor to make any representation and warranty to comply with any applicable law or regulation or to confirm any factual matters reasonably requested by counsel for the Company.

§10. Nonqualified Stock Option. The Option is not intended to qualify as an incentive stock option under §422 of the Internal Revenue Code of 1986, as amended.

§11. Construction. In the event of any inconsistency between the provisions of the Plan and the provisions of this agreement, the provisions of the Plan shall control.

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ACCEPTANCE OF AGREEMENT

The Participant, as of the Grant Date set forth above, hereby: (a) acknowledges receiving a copy of the Plan, which has either been previously delivered to the Participant or is attached to this agreement, and represents to the Company that he/she is familiar with all provisions of the Plan; and (b) accepts this agreement and the Option granted to him/her under this agreement subject to all provisions of the Plan and this agreement.

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