FOR IMMEDIATE RELEASE:
AMERICAN DENTAL PARTNERS ANNOUNCES THE ACCREDITATION OF ANOTHER AFFILIATE

Contacts:  (781) 224-0880, (781) 224-0880
Gregory A. Serrao, Chairman, President and Chief Executive Officer
Breht T. Feigh, Vice President, Chief Financial Officer and Treasurer

WAKEFIELD, MASSACHUSETTS - January 19, 2000 - American Dental Partners, Inc. (NASDAQ:ADPI) announced today that Longhorn Dental Associates, one of its affiliated dental groups in Texas, has received accreditation status from the Accreditation Association for Ambulatory Health Care ("AAAHC").

The AAAHC is a peer-based, not for profit organization that is nationally recognized for conducting extensive evaluations of ambulatory health care organizations to ensure the highest quality standards. Longhorn Dental Associates is one of eleven group dental practices accredited by the AAAHC in the United States, seven of which are affiliated with American Dental Partners.

Longhorn Dental Associates, founded in 1983, is a multi-specialty group practice with eight offices located throughout Austin, Texas. "Longhorn Dental's accreditation is a recognition of the group's clinical excellence. It is well deserved and is validation of their outstanding, high quality practice of dentistry," said Gregory A. Serrao, Chief Executive Officer. "Since our affiliation with Longhorn Dental in December 1996, the dentists, clinical staff and management team of Longhorn Dental, led by Dr. Raymond Scott, have expended tremendous effort to achieve accreditation. Longhorn Dental has set the standard for high quality patient care in Austin and is the only dental group in Texas accredited by the AAAHC," Mr. Serrao added.

American Dental Partners encourages its affiliated dental groups to pursue AAAHC accreditation as a means to set and maintain measurable quality benchmarks and achieve the highest possible standard of patient care. Dr. Jesley C. Ruff, Vice President and Chief Professional Officer of American Dental Partners, works with the Company's affiliates in the pursuit of accreditation. "We hope that by having our affiliated dental groups be part of a select group of dental practices accredited by the AAAHC, American Dental Partners will be at the forefront of promoting clinical excellence in the dental profession," said Dr. Ruff. "While AAAHC accreditation is a rigorous and demanding process, we believe it will help our affiliated dental groups continue to recruit high quality professionals and enhance relationships with patients and local dental communities," Dr. Ruff added.

American Dental Partners is one of the nation's leading business partners to dental groups. The Company is affiliated with 19 dental groups and operates 155 dental facilities with approximately 1,400 operatories located in 14 states. Seven of the Company's affiliated dental groups are accredited by the Accreditation Association for Ambulatory Health Care.

Note: Some of the information in this press release contains "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. The words "believe," "expect," "hope," "anticipate," "project," and similar expressions, among others, identify forward-looking statements. Forward-looking statements speak only as of the date the statement was made. Such forward-looking statements are subject to uncertainties and other factors that could cause actual results to differ materially from those projected, anticipated or implied. Certain factors that might cause such a difference include, among others, risks associated with the tight labor market, access to and cost of capital, the Company's acquisition and affiliation strategy, management of rapid growth, dependence upon affiliated dental groups, dependence upon service agreements, government regulation of the dental industry and year 2000 compliance issues. Additional risks, uncertainties and other factors are set forth in the "Risk Factors" section of the Company's Registration Statement on Form S-4 (File No. 333-56941).