Exhibit 99.1

American Dental Partners, Inc.

401 Edgewater Place, Suite 430

Wakefield, MA 01880

Phone: 781/224-0880                            Fax: 781/224-4216

For Immediate Release

AMERICAN DENTAL PARTNERS REPORTS

SECOND QUARTER FINANCIAL RESULTS

WAKEFIELD, MASSACHUSETTS – July 25, 2011 – American Dental Partners, Inc. (NASDAQ: ADPI) announced financial results today for the quarter ended June 30, 2011.

Comparing results for the second quarter of 2011 with results for the second quarter of 2010:

Comparing results for the six months ending June 30, 2011 with results for the six months ending June, 30, 2010:

For the quarter, patient revenue of the Company’s affiliated dental group practices and Arizona’s Tooth Doctor for Kids was $115,953,000 and same market patient revenue increased 1.0% year-over-year. For the six months ending June 30, 2011, patient revenue of the Company’s affiliated dental group practices and Arizona’s Tooth Doctor for Kids was $233,541,000 and same market patient revenue increased 1.4% year-over-year.

Cash flow from operations was $11,904,000 for the quarter and $25,441,000 for the six months ending June 30, 2011. Amounts paid for acquisitions amounted to $2,563,000 during the quarter and $2,713,000 for the six months ending June 30, 2011. The Company completed seven in-market acquisitions during the quarter and nine in-market acquisitions during the six months ending June 30, 2011. Acquisitions completed during the quarter generated approximately $692,000 of patient revenue in the quarter and are expected to generate patient revenue of approximately $3,300,000 on an annualized basis. Capital expenditures were $4,469,000 for the quarter and $6,845,000 for the six months ending June 30, 2011. The Company completed one de novo facility during the six months ending June 30, 2011.

The Company recognized $545,000, $323,000 net of tax or $0.02 per diluted share, of stock-based compensation expense during the quarter, as compared to $432,000, $260,000 net of tax or $0.02 per diluted share, for the same quarter last year.

As previously announced, the Company refinanced its credit facility in May 2011 by entering into an amended $180,000,000 senior secured credit facility, which includes a $100,000,000 revolving credit facility and an $80,000,000 term loan facility. As a result, included in interest expense, net, for the quarter was $370,000 of expenses associated with the amendment of the Company’s credit facility, $219,000 net of tax or $0.01 per diluted share.

Patient Revenue of the Affiliated Practices

The Company does not consolidate the financial statements of the practices affiliated with the Company by means of service agreements with its financial statements. Patient revenue of the affiliated practices is, however, a financial measure used by the Company’s management to monitor operating performance and to help identify and analyze trends of the affiliated practices that may affect the Company’s business. Most of the operating expenses incurred by the Company, pursuant to the service agreements, are on behalf of the affiliated practices in the operation of dental facilities. These expenses are significantly affected by the patient revenue of the affiliated practices.

Use of Non-GAAP Financial Measures

Adjusted net earnings and adjusted net earnings excluding service agreement amortization are non-GAAP financial measures. In accordance with the requirements of Regulation G of the Securities and Exchange Commission, please see the attached financial tables for a presentation of the most comparable GAAP measures, the reconciliation to those GAAP measures and all additional reconciliations required by Regulation G.

The Company believes non-GAAP financial measures, such as adjusted net earnings and adjusted net earnings excluding service agreement amortization, are important financial measures for understanding its financial performance. Amortization expense of intangible assets related to service agreements with the affiliated practices is presented separately and excluded from the Company’s adjusted net earnings excluding service agreement amortization, a non-GAAP financial measure, due to its magnitude and non-cash impact on the Company’s ongoing operations and because, unlike depreciation of the Company’s dental facilities, it requires no recurring capital investment. The primary limitations associated with the Company’s use of non-GAAP measures are that these measures may not be directly comparable to the amounts reported by other companies. Management compensates for these limitations by providing a detailed reconciliation of the non-GAAP financial measures to the most directly comparable GAAP measures in this press release.

Conference Call

For further discussion of these events and a comprehensive review of the quarter ending June 30, 2011, the Company will host its previously announced conference call on Tuesday, July 26, 2011 at 9:00 a.m., EDT, which will be broadcast live over the Internet at www.amdpi.com. The call will be hosted by Gregory A. Serrao, Chairman, President and Chief Executive Officer. To access the webcast, participants should visit the Investors section of the website at least 15 minutes prior to the start of the conference call to download and install any necessary audio software. A replay of the webcast will be available at www.amdpi.com approximately two hours after the call through 6:00 p.m., EDT, Tuesday, August 2, 2011.

About American Dental Partners, Inc.

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 278 dental facilities with approximately 2,387 operatories located in 21 states.

Use of Forward-Looking Statements

“Safe Harbor” Statement under the Private Securities Litigation Reform Act of 1995: With the exception of the historical information contained in this press release, the matters described herein contain “forward-looking” statements that involve risk and uncertainties that may individually or collectively affect 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 the 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 filings with the Securities and Exchange Commission, including its annual report on Form 10-K and quarterly reports on Form 10-Q.

AMERICAN DENTAL PARTNERS, INC.

FINANCIAL HIGHLIGHTS

(in thousands, except per share amounts)

(unaudited)

AMERICAN DENTAL PARTNERS, INC.

FINANCIAL HIGHLIGHTS

(in thousands)

(unaudited)

AMERICAN DENTAL PARTNERS, INC.

SUPPLEMENTAL OPERATING DATA

(unaudited)

Selected Statistical Data

Patient Revenue and Same Market Patient Revenue Growth (c)

(in thousands)

AMERICAN DENTAL PARTNERS, INC.

SUPPLEMENTAL OPERATING DATA

(in thousands)

(unaudited)

Components of Same Market Patient Revenue Growth (in thousands)

Reconciliation of GAAP Net Earnings, as Reported, to Non-GAAP Diluted Adjusted Net Earnings

(in thousands, except per share amounts)