<PAGE>
Prospectus Supplement
Filed pursuant to Rule 424(b)(3)
File No. 333-56941
_______________________
AMERICAN DENTAL PARTNERS, INC.
750,000 Shares of Common Stock
and
$25,000,000 Aggregate Principal Amount of
Subordinated Promissory Notes
March 16, 1999
_______________________
This Prospectus Supplement relates to the Prospectus dated November 25,
1998 covering our offer and sale of up to 750,000 shares of our Common Stock and
up to $25,000,000 aggregate principal amount of our Subordinated Promissory
Notes which we may issue from time to time in connection with the future direct
and indirect acquisition and affiliation transactions.
As of March 16, 1999, 730,446 shares of our Common Stock and $24,405,000 of
our Subordinated Promissory Notes remain available for future issuance.
Recent Developments
-------------------
Since December 31, 1998, we have acquired substantially all the assets of
two dental practices and simultaneously entered into a 40-year service agreement
with one of the affiliated dental groups. The dentists of the other dental
group joined an existing affiliate. The two dental groups are Dental Care of
Alabama in Birmingham and Tuscaloosa; and the dental facilities formerly part of
CIGNA HealthCare of Arizona, Inc. in Phoenix. The aggregate purchase price paid
in connection with these transactions consisted of approximately $3.9 million in
cash, $0.1 million in Subordinated Promissory Notes and $0.1 million in deferred
payments.
In addition, we are currently in discussions with a number of dentists and
owners of dental group practices about possible affiliations with us. There can
be no assurance that we will consummate any of these possible affiliations.
Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved any of the securities offered by this
Prospectus or determined that this Prospectus is accurate or complete.
Financial Information
---------------------
Our financial highlights for the three months ended December 31, 1998 and
for the year ended December 31, 1998 are set forth in the tables that follow.
-Tables to Follow-
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AMERICAN DENTAL PARTNERS, INC.
FINANCIAL HIGHLIGHTS
(in thousands, except per share amounts)
<TABLE>
<CAPTION>
Three Months Ended Years Ended
December 31, December 31,
1998 1997 1998 1997
---- ---- ---- ----
<S> <C> <C> <C> <C>
(unaudited)
Net revenue...................... $23,368 $16,650 $84,090 $53,270
------- ------- ------- -------
Operating expenses:
Salaries and benefits............ 11,726 8,813 43,190 28,438
Lab fees and dental supplies..... 3,009 1,944 10,796 6,435
Office occupancy................. 2,103 1,446 7,635 4,814
Other operating expenses......... 1,817 1,831 6,840 6,264
General corporate expenses....... 949 1,077 3,951 3,337
Depreciation..................... 692 426 2,495 1,580
Amortization of intangibles...... 495 296 1,732 645
------- ------- ------- -------
Total operating expenses......... 20,791 15,833 76,639 51,513
------- ------- ------- -------
Earnings from operations......... 2,577 817 7,451 1,757
Interest expense, net............ 247 368 1,085 563
------- ------- ------- -------
Earnings before income taxes..... 2,330 449 6,366 1,194
Income taxes..................... 906 43 2,480 124
------- ------- ------- -------
Net earnings..................... $ 1,424 $ 406 $ 3,886 $ 1,070
======= ======= ======= =======
Net earnings (loss)
per common share:
Basic............................ $ 0.19 $ 0.04 $ 0.59 $ (0.05)
Diluted.......................... $ 0.19 $ 0.04 $ 0.54 $ (0.05)
Weighted average common
shares outstanding:
Basic............................ 7,436 2,394 5,907 2,273
Diluted.......................... 7,671 2,593 6,867 2,273
</TABLE>
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AMERICAN DENTAL PARTNERS, INC.
FINANCIAL HIGHLIGHTS
(in thousands)
<TABLE>
<CAPTION>
December 31, December 31,
1998 1997
---- ----
<S> <C> <C>
ASSETS
Current assets:
Cash and cash equivalents.................... $ 2,091 $ 4,675
Receivables due from affiliated practices.... 4,579 3,207
Other current assets......................... 2,302 2,119
------- -------
Total current assets......................... 8,972 10,001
------- -------
Property and equipment, net.................. 12,943 8,752
------- -------
Non-current assets:
Intangible assets, net....................... 47,152 28,975
Other assets................................. 1,468 231
------- -------
Total non-current assets..................... 48,620 29,206
------- -------
Total assets................................. $70,535 $47,959
======= =======
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
Accounts payable and accrued expenses........ $10,618 $ 8,468
Current maturities of debt................... 1,079 774
------- -------
Total current liabilities.................... 11,697 9,242
------- -------
Non-current liabilities:
Long-term debt............................... 9,980 21,253
Other liabilities............................ 553 258
------- -------
Total non-current liabilities................ 10,533 21,511
------- -------
Total liabilities............................ 22,230 30,753
------- -------
Series A convertible preferred stock......... - 8,641
Series B redeemable preferred stock.......... - 7,656
Stockholders' equity......................... 48,305 909
------- -------
Commitments and contingencies
Total liabilities and stockholders' equity... $70,535 $47,959
======= =======
</TABLE>
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