<PAGE>

================================================================================

                      SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C. 20549

                               -----------------

                                 FORM 10-K/A-1


[X]  ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
     SECURITIES EXCHANGE ACT OF 1934

                  For the fiscal year ended December 31, 2000
                                      OR

[ ]  TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
     SECURITIES EXCHANGE ACT OF 1934

                      For the transition period from   to

                        Commission File Number: 1-13263

                          CASTLE DENTAL CENTERS, INC.

                                   Delaware
        (State or other jurisdiction of incorporation or organization)

                                  76-0486898
                     (I.R.S. Employer Identification No.)

                      1360 Post Oak Boulevard, Suite 1300
                                Houston, Texas
                   (Address of principal executive offices)

                                     77056
                                  (Zip Code)

                                (713) 479-8000
             (Registrant's telephone number, including area code)

       Securities Registered Pursuant to Section 12(b) of the Act:  None
          Securities Registered Pursuant to Section 12(g) of the Act:
                         Common Stock, $.001 Par Value
                               (Title of Class)

Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days.  Yes [X]  No [ ]

Indicate by check mark if the disclosure of delinquent filers pursuant to Item
405 of Regulation S-K ( 229.405 under the Securities Exchange Act of 1934) is
not contained herein, and will not be contained, to the best of registrant's
knowledge, in definitive proxy or information statements incorporated by
reference in Part III of this Form 10-K or any amendment to this Form 10-K. [X]

As of April 16, 2001, there were 6,417,206 shares of Castle Dental Centers, Inc.
Common Stock, $.001 par value, issued and outstanding, of which 3,293,363,
having an aggregate market value of approximately $0.4 million, were held by
non-affiliates of the registrant.

Documents Incorporated by Reference:  None.

================================================================================
<PAGE>

                                   PART III

ITEM 10.  DIRECTORS AND EXECUTIVE OFFICERS OF THE REGISTRANT

Board of Directors

The following sets forth information as to the current directors and executive
officers of the Company, including their ages, present principal occupations,
other business experience during the last five years, memberships on committees
of the Board of Directors and directorships in other publicly-held companies.


                                                                        Director
     Name               Age     Position with the Company                 Since
     ----               ---     -------------------------               --------

Ira Glazer               49     Chief Executive Officer

Jack H. Castle, Jr.      46     Chairman of the Board                       1995

Jack H. Castle, D.D.S.   79     Director                                    1995

Robert J. Cresci (1)(2)  57     Director                                    1995

G. Kent Kahle (1)        49     Director                                    1995

Emmett E. Moore(1)       58     Director                                    1997

John M. Slack            53     Vice President and Chief Financial Officer

________________________
(1) Member of the Audit Committee.
(2) Member of the Compensation Committee.

Jack H. Castle, Jr. became a director in December 1995. He was a co-founder of
the Company in 1981 and served as Chief Executive Officer from 1990 until
February 2001. He became the Company's Chairman in August 1996. Mr. Castle
received a B.A. from Rollins College and a Masters of Business Administration
from Wake Forest University. Mr. Castle is the son of Jack H. Castle, D.D.S.

Jack H. Castle, D.D.S. became a director in December 1995 and served as Chairman
of the Company from 1981 until August 1996. He is also the sole owner of Jack H.
Castle, D.D.S., P.C., a dental practice managed by the Company (the "Texas PC").
Prior to co-founding the Company, Dr. Castle operated a single location dental
practice. Dr. Castle graduated from the University of Houston in 1943 and
received a Doctorate of Dental Surgery from the University of Texas Health
Science Center in Houston in 1945. He served in the United States Navy from 1947
to 1949. Dr. Castle is the father of Jack H. Castle, Jr.

Robert J. Cresci became a director in December 1995. Mr. Cresci has been a
Managing Director of Pecks Management Partners Ltd., an investment management
firm, since September 1990. Mr. Cresci currently serves on the boards of
Sepracor, Inc., Inc., Aviva Petroleum Ltd., Film Roman, Inc., Quest Educational
Corporation, Jfax.Com, Inc., Candlewood Hotel Co., Inc., SeraCare, Inc., E-Stamp
Corporation and several private companies.

G. Kent Kahle became a director in December 1995. He has been a Managing
Director of The GulfStar Group, Inc., an investment banking firm, since 1990.
From 1982 to 1990 Mr. Kahle held various positions with Rotan Mosle, Inc., most
recently as Senior Vice President and Director. Mr. Kahle has a Masters of
Business Administration from The Wharton School of the University of
Pennsylvania and an A.B. from Brown University. He currently serves on the board
of Total Safety Corporation, U.S. Legal Support, Inc, Plassein Packaging Corp.
and De-Ro Products, Inc.

                                       2
<PAGE>

Emmett E. Moore became a director in September 1997. Since June 1999, Mr. Moore
has been Chairman of the Board and Chief Executive Officer of MedEvolve, Inc., a
provider of internet-based information technology solutions to physicians'
offices. From November 1997 until joining MedEvolve, he was engaged in private
consulting and investments related to healthcare. From April 1995 until November
1997, Mr. Moore was the Chairman of the Board and Chief Executive Officer of
Physicians Resource Group, Inc., a publicly-traded ophthalmology practice
management company. Mr. Moore received B.B.A., J.D. and M.P.A. degrees from the
University of Texas, and is a certified public accountant.

Executive Officers

The Board elects executive officers annually at its first meeting following the
annual meeting of stockholders. Information concerning Ira Glazer and John M.
Slack is set forth below.

Ira Glazer became acting Chief Executive Officer of the Company in February
2001. He is a Senior Vice President of Getzler & Co., a New York-based
turnaround specialist. Prior to joining Getzler & Co., Mr. Glazer was with
Maidenform Worldwide Inc., where he served as Chief Financial Officer and Chief
Operating Officer. Before joining Maidenform, Mr. Getzler spent ten years with
Chase Manhattan Bank, where he was a Vice President and Division Executive
in middle market lending. Mr. Glazer received a B.B.A. from Pace University in
1974.

John M. Slack joined the Company in December 1995 as Vice President and Chief
Financial Officer. From November 1994 through November 1995, he served as Vice
President and Chief Financial Officer of Team, Inc., a publicly-held
environmental services company. From 1985 through August 1994, Mr. Slack was
Vice President and Chief Financial Officer of Serv-Tech, Inc., a publicly-held
industrial services company. Mr. Slack received a B.S. in international
economics from Georgetown University in 1969.

Section 16(a) Beneficial Ownership Reporting Compliance

Section 16(a) of the Securities Exchange Act of 1934 requires the Company's
directors, officers and persons holding more than ten percent of a registered
class of the Company's equity securities to file with the SEC and any stock
exchange or automated quotation system on which the Common Stock may then be
listed or quoted (i) initial reports of ownership, (ii) reports of changes in
ownership and (iii) annual reports of ownership of Common Stock and other equity
securities of the Company. Such directors, officers and ten-percent stockholders
are also required to furnish the Company with copies of all such filed reports.

Based solely upon review of the copies of such reports furnished to the Company
and written representations that no other reports were required during 2000, the
Company believes that all of the Company's executive officers and directors
complied with Section 16(a) reporting requirements during 2000.

                                       3
<PAGE>

ITEM 11. EXECUTIVE COMPENSATION

Summary Compensation Table

The following table provides certain summary information concerning compensation
earned by the Company's Chief Executive Officer and each of the other executive
officers of the Company (the "Named Executive Officers") whose compensation
exceeded $100,000 during the year ended December 31, 2000.


<TABLE>
<CAPTION>
                                                            Annual Compensation                Long-term Compensation
                                               ---------------------------------------------   -----------------------
                                                                                Other Annual    Restricted   Number of    All Other
Name and Principal                              Salary            Bonus         Compensation   Stock Awards   Options   Compensation
     Position                     Year            ($)              ($)               ($)           ($)        Granted       ($)(1)
------------------                ----          ------            -----         ------------   ------------  ---------  ------------
<S>                               <C>           <C>               <C>           <C>            <C>           <C>          <C>
Jack H. Castle, Jr.(2)            2000          251,790               -                  -               -           -        3,365
Chief Executive                   1999          249,925               -                  -               -      75,000        3,504
Officer                           1998          243,663               -                  -               -      75,000       12,388

G. Daniel Siewert III (2)         2000          202,115               -                  -               -           -       12,000
President,                        1999          199,929               -                  -               -      75,000       12,000
Chief Operating Officer           1998          199,320               -                  -               -      75,000       12,000

John M. Slack                     2000          150,000               -                  -               -           -        9,912
Vice President,                   1999          144,231               -                  -               -      50,000        7,407
Chief Financial Officer,          1998          142,026               -                  -               -      50,000            -
 Treasurer and Secretary
</TABLE>

(1)  Other compensation paid to Mr. Castle, Mr. Siewert and Mr. Slack in 1998,
     1999 and 2000 consisted of automobile allowances.
(2)  Mr. Castle resigned as Chief Executive Officer and Mr. Siewert resigned as
     President and Chief Operating Officer, each as of February 15, 2001.

Stock Options

There were no stock options granted to the Named Executive Officers during 2000.

Aggregate Option Exercises in 2000 and Year-End 2000 Option Values

The following table reflects certain information concerning the number of
unexercised options held by the Named Executive Officers and the value of such
officers' unexercised options as of December 31, 2000. No options were exercised
by the Named Executive Officers during the year ended December 31, 2000.


<TABLE>
<CAPTION>
                                                                             Number of                  Value of Unexercised
                                                                        Unexercised Options            "In-the-Money" Options
                                                                        at December 31, 2000           at December 31, 2000(1)
                                    Shares Acquired     Value        ---------------------------    ----------------------------
       Name                           on Exercise      Realized      Exercisable   Unexercisable    Exercisable    Unexercisable
       ----                           -----------      --------      -----------   -------------    -----------    -------------
<S>                                   <C>              <C>           <C>           <C>              <C>            <C>
Jack H. Castle, Jr...................      0              $0            116,250       133,750           $0              $0
G. Daniel Siewert III................      0               0            126,250       133,750            0               0
John M. Slack........................      0               0             75,500        74,500            0               0
</TABLE>

(1)  Options are "in-the-money" if the closing market price of the Company's
     Common Stock exceeds the exercise price of the options. The exercise price
     of the options granted to the Named Executive

                                       4
<PAGE>

     Officers ranges from $2.3125 to $10.00 per share. None of the options
     granted to the Named Executive Officers were "in-the-money" at December 31,
     2000.

Compensation Committee Interlocks and Insider Participation

In 2000, the members of the Compensation Committee were Elizabeth A. Tilney and
Robert J. Cresci. Ms. Tilney resigned from the board of directors in February
2001.  Mr. Cresci is a party to certain transactions with the Company.  See
"Certain Relationships and Related Transactions."


ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

Principal Stockholders

The following table sets forth information as of March 31, 2001 with respect to
beneficial ownership of the Company's Common Stock by (i) each director, (ii)
each executive officer, (iii) the executive officers and directors as a group,
and (iv) each person known to the Company who beneficially owns 5% or more of
the outstanding shares of its voting securities. Unless otherwise indicated,
each of the stockholders has sole voting and investment power with respect to
the shares beneficially owned.

<TABLE>
<CAPTION>
                                                        Number of    Percentage
                                                         Shares      of Shares
     Name and Address of                              Beneficially  Beneficially
      Beneficial Owner                                    Owned        Owned
     -------------------                              ------------  ------------
<S>                                                   <C>           <C>
Jack H. Castle, Jr. (1)(2)..........................    1,444,450      22.2

Jack H. Castle, D.D.S. (2)(3).......................      974,000      15.2

Loretta Castle (2)(3)...............................      974,000      15.2

Castle Interests, Ltd. (2)..........................      514,000       8.0
1360 Post Oak Boulevard,
Suite 1300, Houston, Texas 77056

Pecks Management Partners, Ltd. (4).................      913,243      14.2
One Rockefeller Plaza, Suite 900
New York, New York 10020

Robert J. Cresci (5)................................      928,423      14.5

Capital Group International, Inc....................      625,000       9.7
11100 Santa Monica Blvd., 15th Floor
Los Angeles, California 90025

Hathaway & Associates Ltd...........................      449,400       7.0
119 Rowayton Avenue
Rowayton Connecticut 06853

Benson Associates, LLC..............................      400,400       6.2
111 S.W. Fifth Avenue, Suite 2130
Portland, Oregon 97204

G. Kent Kahle (6)...................................       23,750        *

John M. Slack (7)...................................       90,000       1.4

Emmett E. Moore (8).................................       15,000        *

All directors and executive officers as a group
 (8 persons) (9)....................................    2,961,243      44.5%
</TABLE>

                                       5
<PAGE>

*  Less than 1%

(1)  Includes 714,000 shares held by the Castle 1995 Gift Trust f/b/o Jack H.
     Castle, Jr., of which Mr. Castle is Trustee. Includes options to acquire
     116,250 shares of Common Stock issued under the Castle Dental Centers, Inc.
     Omnibus Stock and Incentive Plan (the "Plan") which are exercisable within
     60 days. Excludes options to acquire 133,750 shares of Common Stock which
     are not exercisable within 60 days.

(2)  Includes 514,000 shares of Common Stock owned of record by Castle Interest,
     Ltd., a Texas limited partnership of which Jack H. Castle, D.D.S., Loretta
     Castle and Jack H. Castle, Jr. are the three general partners. The general
     partners of Castle Interests, Ltd. cannot act to vote or dispose of shares
     of Common Stock held by Castle Interests, Ltd. without the unanimous vote
     of all of the general partners. Loretta Castle is the wife of Jack H.
     Castle, D.D.S. and the mother of Jack H. Castle, Jr.

(3)  Includes 103,000 shares of Common Stock owned jointly by Jack H. Castle,
     D.D.S. and Loretta Castle.

(4)  Includes 615,033, 121,708, and 176,502 shares of Common Stock owned of
     record by Delaware State Employees' Retirement Fund, Declaration of Trust
     for Defined Benefit Plans of ICI American Holdings Inc. and Declaration of
     Trust for Defined Benefit Plans of Zeneca Holdings Inc., respectively (the
     "Pecks Investors"). Pecks Management Partners Ltd. ("Pecks"), as investment
     manager for the Pecks Investors, has sole investment and voting power with
     respect to such shares. Mr. Cresci, a director of the Company, is a
     Managing Director of Pecks. Pecks disclaims beneficial ownership of such
     shares.

(5)  Includes all shares deemed to be beneficially owned by Pecks, of which Mr.
     Cresci is a Managing Director. As a result, Mr. Cresci may be deemed to
     share voting and investment power with respect to such shares. Mr. Cresci
     disclaims beneficial ownership of such shares. See note 4 above. Also
     includes options to acquire 15,000 shares of Common Stock under the
     Directors' Plan which are exercisable within 60 days. Excludes options to
     acquire 10,000 shares of Common Stock which are not exercisable within 60
     days.

(6)  Includes options to acquire 17,500 shares of Common Stock under the
     Directors' Plan which are exercisable within 60 days. Excludes options to
     acquire 15,000 shares of Common Stock which are not exercisable within 60
     days.

(7)  Includes options to acquire 75,500 shares of Common Stock issued under the
     Plan which are exercisable within 60 days. Excludes options to acquire
     74,500 shares of Common Stock which are not exercisable within 60 days.

(8)  Includes options to acquire 15,000 shares of Common Stock issued under the
     Plan which are exercisable within 60 days. Excludes options to acquire
     10,000 shares of Common Stock which are not exercisable within 60 days.

(9)  Includes (i) 714,000 shares of Common Stock held by the Castle 1995 Gift
     Trust f/b/o Jack H. Castle, Jr., (ii) 514,000 shares of Common Stock held
     by Castle Interests, Ltd. and (iii) 913,243 shares of Common Stock
     beneficially owned by the Pecks Investors.


ITEM 13.  CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS

Mr. Kahle, a director of the Company, is a Managing Director of The GulfStar
Group, Inc., which has provided investment banking and advisory services to the
Company. The Company has paid The GulfStar

                                       6
<PAGE>

Group, Inc. for investment banking and financial advisory services provided to
the Company in connection with certain acquisitions. In 1998, The GulfStar
Group, Inc. received a $183,332 advisory fee in connection with the acquisition
of Dental Consulting Services, LLC. The directors of the Company other than Mr.
Kahle approve the payments made to The GulfStar Group, Inc. by the Company.

At December 31, 2000, Jack H. Castle, Jr., the Company's Chief Executive
Officer, G. Daniel Siewert, the Company's President and Chief Operating Officer,
and John M. Slack, Vice-President and Chief Financial Officer, had outstanding
loans in the aggregate amount of $307,000 from the Company.  These loans are
repayable over varying periods ranging from one to five years and bear interest
at rates ranging from zero to six percent.

Mr. Cresci, a director of the Company, is a Managing Director of Pecks
Management Partners Ltd., the investment advisor to the Pecks Investors, which
owns 948,243 shares of Common Stock. Pursuant to the provisions of the
Stockholders Agreement between the Company, Pecks Management Partners Ltd. and
certain members of Jack H. Castle, Jr.'s family, for so long as certain
ownership thresholds with respect to the Common Stock are maintained, the other
shareholders party to such agreement are obligated to vote their shares of
Common Stock in favor of the designee of the Pecks Investors to be a member of
the Company's board of directors and Mr. Cresci is currently such nominee.

In December 1995, the Company acquired all of the stock of Jack H. Castle,
D.D.S., Inc., a professional corporation of which Jack H. Castle, D.D.S., a
director of the Company, was the sole owner. In connection with that
transaction, the Company paid Jack H. Castle, D.D.S. $6.0 million in cash and
entered into a Deferred Compensation Agreement with Jack H. Castle, D.D.S.
pursuant to which the Company has agreed to pay Jack H. Castle, D.D.S. $2.6
million in 20 quarterly installments of $131,500 beginning March 1996 and ending
in December 2000.

In connection with the purchase of the stock of Jack H. Castle, D.D.S., Inc.,
the Company also entered into a management services agreement with Jack H.
Castle, D.D.S., P.C., a professional corporation of which Jack H. Castle, D.D.S.
is the sole owner. Pursuant to the management services agreement, Jack H.
Castle, D.D.S., P.C. receives an annual payment of $100,000 for services
performed in connection therewith. The professional corporation employs or
contracts with all of the dental professionals practicing at the Company's
dental offices in Texas under the Management Agreement. The Company provides the
professional corporation with, among other things, equipment, supplies, support
services, non-dental personnel, office space, management, administration,
financial record keeping and reporting services. The Management Agreement is for
a term of 25 years, with automatic renewal thereafter.

The Company receives a management fee under the Management Agreement with Jack
H. Castle, D.D.S., P.C. equal to the Company's costs plus a base management fee
and a performance fee. The base management fee is equal to 12.5% of adjusted
gross revenues and the performance fee is equal to the professional
corporation's net income after payment of all other fees and expenses. The
Company's costs include all direct and indirect costs, overhead and expenses
relating to the Company's provision of services to the professional corporation
under the Management Agreement.

In addition to the Management Agreement with Jack H. Castle, D.D.S., P.C., the
Company has a contractual right to designate or approve the licensed dentist or
dentists who own the professional corporation's capital stock in the event Jack
H. Castle, D.D.S. ceases to be affiliated with the Company for any reason.

The Company is party to a lease agreement with Goforth, Inc., a company owned by
Jack H. Castle, Jr., the Company's Chairman and Chief Executive Officer. The
lease agreement relates to the Castle Dental Center located at 2101 West Loop
South in Houston, Texas, a 6,781 square foot free-standing building. The Company
has agreed to pay Goforth, Inc. a minimum guaranteed rental of $12,000 per month
through January 2001 and $13,200 per month from January 2001 through January
2006. The Company has also agreed to pay

                                       7
<PAGE>

additional rent of approximately $1,600 per month for insurance, taxes and
common area maintenance. The Company believes that this lease agreement is on
terms no less favorable to the Company than could have been obtained with an
independent third party.

Pursuant to a Registration Rights Agreement dated as of December 18, 1995, as
amended, the Pecks Investors and certain members of Jack H. Castle, Jr.'s family
have been granted certain registration rights by the Company with respect to the
shares of Common Stock owned by them.

                                       8
<PAGE>

                                  SIGNATURES

     Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, as amended, the Registrant has duly caused this Annual
Report on Form 10-K/A-1 to be signed on its behalf by the undersigned, thereunto
duly authorized, on this 30th day of April, 2001.

                                  CASTLE DENTAL CENTERS, INC.


                                  By: /s/ JOHN M. SLACK
                                      ------------------------------------------
                                      John M. Slack
                                      Vice President and Chief Financial Officer

     Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, as amended, this Annual Report on Form 10-K/A-1 has been
signed below by the following persons in the capacities indicated below on this
30th day of April, 2001.

                Signature                               Title
                ---------                               -----

         /s/ JACK H. CASTLE, JR.*               Chairman of the Board
-------------------------------------------
            Jack H. Castle, Jr.


             /s/ IRA GLAZER*                     Chief Executive Officer
-------------------------------------------   (Principal Executive Officer)
                Ira Glazer


            /s/ JOHN M. SLACK*                     Vice President and
-------------------------------------------     Chief Financial Officer
              John M. Slack                    (Principal Financial and
                                                  Accounting Officer)

        /s/ JACK H. CASTLE, D.D.S.*                     Director
-------------------------------------------
            Jack H. Castle, D.D.S.


          /s/ ROBERT J. CRESCI*                         Director
-------------------------------------------
             Robert J. Cresci


           /s/ G. KENT KAHLE*                           Director
-------------------------------------------
              G. Kent Kahle


          /s/ EMMETT E. MOORE*                          Director
-------------------------------------------
             Emmett E. Moore


*By:        /s/ JOHN M. SLACK
-------------------------------------------
     John M. Slack, Attorney-in-Fact


                                       9