ADPI American Dental Partners, Inc. (MM)

American Dental Partners, Inc. (NASDAQ: ADPI) announced today that the underwriter of its previously announced public offering has exercised its over-allotment option to purchase an additional 339,000 shares at a price of $12.00 per share to the public with net proceeds to the Company of approximately $3,844,260 after deducting underwriting discounts and commissions. The purchase by the underwriter of the additional shares closed today.

Robert W. Baird & Co. acted as the sole underwriter for the public offering.

American Dental Partners is one of the nation's leading business partners to dental group practices. The Company is affiliated with 26 dental group practices which have 242 dental facilities with approximately 2,131 operatories located in 18 states.

"Safe Harbor" Statement under the Private Securities Litigation Reform Act of 1995: With the exception of the historical information contained in this news release, the matters described herein contain "forward-looking" statements that involve risk and uncertainties that may individually or collectively impact the matters herein described, including but not limited to the Company's risks associated with overall or regional economic conditions, dependence upon affiliated dental practices, contracts its affiliated practices have with third-party payors, government regulation of the dental industry, impact of health care reform, dependence upon service agreements and the impact of any terminations or potential terminations of such contracts, business interruptions, the outcome of pending litigation and the Company's acquisition and affiliation strategy, which are detailed from time to time in the "Risk Factors" section of the Company's SEC reports, including the annual report on Form 10-K for the year ended December 31, 2008 and quarterly reports on Form 10-Q.

Contacts: Gregory A. Serrao Chairman, President and Chief Executive Officer 781-224-880 Breht T. Feigh Executive Vice President, Chief Financial Officer and Treasurer 781-224-0880 American Dental Partners, Inc. 401 Edgewater Place, Suite 430 Wakefield, MA 01880 Phone: 781/224-0880 Fax: 781/224-4216