American Dental Partners Announces Common Stock Offering

WAKEFIELD, MA--(Marketwire - August 18, 2009) - American Dental Partners, Inc. (NASDAQ: ADPI)
announced today that it has commenced a public offering of 2,260,000 shares
of common stock. American Dental Partners will grant the underwriter in
the offering an option to purchase up to 339,000 additional shares of
common stock at the same price per share to cover any over-allotments.

American Dental Partners expects to use the net proceeds from the offering
for repayment of outstanding indebtedness and other general and working
capital purposes.

Robert W. Baird & Co. will act as the sole underwriter for the offering.
The offering is being made only by means of a prospectus and related
prospectus supplement, copies of which may be obtained upon request to
Robert W. Baird & Co. Incorporated, 777 East Wisconsin Avenue, Galleria
Level, Milwaukee, Wisconsin 53202-5391, or by calling 1-800-792-2413.
Copies of the prospectus and prospectus supplement are also available on
the Securities and Exchange Commission website at www.sec.gov.

The shares are being offered pursuant to an effective registration
statement. This press release does not constitute an offer to sell these
securities or a solicitation of an offer to buy these securities, nor shall
there be any sale of these securities in any state or jurisdiction in which
such an offer, solicitation or sale would be unlawful prior to registration
or qualification under the securities laws of any such state or
jurisdiction.

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 its ability to refinance its credit
facilities on satisfactory terms, 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.