Document:

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                                                                    EXHIBIT 10.4

                                                                  EXECUTION COPY

                             STOCKHOLDERS AGREEMENT

          STOCKHOLDERS AGREEMENT dated as of May 15, 2003, by and among Castle
Dental Centers, Inc., a Delaware corporation (the "Company"), Sentinel Capital
Partners II, L.P. ("Sentinel"), General Electric Capital Corporation, a Delaware
corporation ("GE"), Midwest Mezzanine Fund II, L.P., a Delaware limited
partnership ("Midwest"), James M. Usdan ("Usdan"), John M. Slack ("Slack"), and
Thomas Fitzpatrick ("Fitzpatrick"). Sentinel, GE, Midwest, Usdan, Slack and
Fitzpatrick and any other Person who becomes a party hereto and their Permitted
Transferees are collectively referred to as the "Stockholders" and individually
as a "Stockholder." Capitalized terms used herein but not otherwise defined have
the meaning set forth in Section 1.

          WHEREAS, the Company, Sentinel, Fitzpatrick, GE, Midwest, Slack and
Usdan are parties to a Preferred Stock and Subordinated Note Purchase Agreement
dated as of the date hereof (the "Purchase Agreement"). In order to induce
Sentinel, Fitzpatrick, GE, Midwest, Slack and Usdan to enter into the Purchase
Agreement, the Stockholders have agreed to enter into this Agreement for the
purposes, among others, of (i) establishing the composition of the Board, (ii)
assuring continuity in the management and ownership of the Company and (iii)
limiting the manner and terms by which the Stockholder Shares may be
transferred. The execution and delivery of this Agreement is a condition to the
Closing under the Purchase Agreement. It is acknowledged that certain other
parties shall become a party to this Agreement following the date hereof in
conjunction with such parties' execution of a joinder to the Purchase Agreement
and their purchase of certain securities of the Company thereunder.

          NOW, THEREFORE, in consideration of the mutual covenants contained
herein and other good and valuable consideration, the receipt and sufficiency of
which are hereby acknowledged, the parties hereby agree as follows:

          1.     Definitions. As used herein, the following terms shall have the
following meanings:

          "Affiliate" shall mean, as to any Person, any other Person which
directly or indirectly controls, or is under common control with, or is
controlled by, such Person. As used in this definition, "control" (including,
with its correlative meanings, "controlled by" and "under common control with")
shall mean possession, directly or indirectly, of power to direct or cause the
direction of management or policies (whether through ownership of securities or
partnership or other ownership interests, by contract or otherwise); provided,
that beneficial ownership of 10% or more of the voting securities (or the
equivalents) of a Person shall be deemed to be control.

          "Agreement" has the meaning given thereto in the preamble.

          "Approved Sale" means a Sale of the Company which has been approved by
both the Board and Sentinel so long as Sentinel holds as least a majority of the
Sentinel Stockholder Shares outstanding on the date of this Agreement; provided
that the purchaser (or the equivalent) with respect to such Sale of the Company
is not Sentinel or an Affiliate of Sentinel.

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          "Board" means the Company's board of directors.

          "Bylaws" means the Bylaws of the Company and subsequent amendments
thereto.

          "Certificate of Incorporation" means the Certificate of Incorporation
of the Company, as amended from time to time.

          "Change of Control" means: (i) the sale, lease, transfer, conveyance
or other disposition, in one or a series of related transactions, of all or
substantially all the assets of the Company and its Subsidiaries taken as a
whole to any "person" (as such term is used in Section 13(d)(3) of the
Securities Exchange Act), or (ii) the consummation of any transaction (including
any merger or consolidation) the result of which is that any "person" (as
defined above), other than Sentinel Capital Partners II L.P. and/or its
Affiliates, becomes the beneficial owner (as determined in accordance with Rules
13d-3 and 13d-5 under the Securities Exchange Act except that a person will be
deemed to have beneficial ownership of all shares that such person has the right
to acquire, whether such right is exercisable immediately or only after the
passage of time), directly or indirectly, of more than 50% of the Voting
Securities of the Company.

          "Common Stock" means the Company's Common Stock, par value $0.000001
per share.

          "Common Stock Deemed Outstanding" means the number of shares of Common
Stock outstanding, determined on a fully diluted as if converted basis giving
effect to all outstanding Common Stock and all outstanding securities
convertible into or exchangeable for Common Stock and any options (reserved for
issuance as approved by the Board or issued), warrants or other rights to
acquire Common Stock (collectively, "Common Stock Equivalents").

          "Company" has the meaning given thereto in the preamble.

          "Election Notice" has the meaning given thereto in Section 6(a).

          "Family Group" means, with respect to an individual Stockholder, such
Stockholder's spouse and descendants (whether natural or adopted) and any trust
solely for the benefit of such Stockholder and/or such Stockholder's spouse,
their respective ancestors and/or descendants (whether natural or adopted).

          "Fitzpatrick" has the meaning given thereto in the preamble.

          "GE" has the meaning given thereto in the preamble.

          "Immediate Family" means an individual's spouse, descendants (whether
natural or adopted), siblings, parents or grandparents.

          "Indebtedness" means at a particular time, without duplication, (i)
any indebtedness for borrowed money or issued in substitution for or exchange of
indebtedness for borrowed money, (ii) any indebtedness evidenced by any note,
bond, debenture, or other debt security, (iii) any indebtedness for the deferred
purchase price of property or services with

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respect to which a Person is liable, contingently or otherwise, as obligor or
otherwise (other than trade payables and other current liabilities), (iv) any
commitment by which a Person assures a creditor against loss (including
contingent reimbursement obligations with respect to letters of credit), (v) any
indebtedness guaranteed in any manner by a Person (including guarantees in the
form of an agreement to repurchase or reimburse), (vi) any obligations under
capitalized leases with respect to which a Person is liable, contingently or
otherwise, as obligor, guarantor or otherwise, with respect to which obligations
a Person assures a creditor against loss, (vii) any indebtedness secured by a
lien on a Person's assets and (viii) any unsatisfied obligation for "withdrawal
liability" to a "multiemployer plan" as such terms are defined under the
Employee Retirement Income Security Act of 1974, as amended.

          "Issuance Notice" has the meaning given thereto in Section 6(a).

          "Joinder Agreement" means an agreement, in the form of Exhibit A,
pursuant to which a holder of Stockholder Shares becomes a party to, and subject
to the obligations of, this Agreement.

          "Midwest" has the meaning given thereto in the preamble.

          "Non-Sentinel Directors" has the meaning given thereto in Section
2(a)(i)(B).

          "Non-Sentinel Stockholder Shares" means the Stockholder Shares issued
or issuable to, or otherwise held by, GE, Midwest, Usdan and their respective
Affiliates. Any reference herein to a "holders of a majority of the Non-Sentinel
Stockholder Shares", means the holders of a majority of the Non-Sentinel
Stockholder Shares on a fully diluted as if converted basis.

          "Notes" means the Subordinated Promissory Notes issued to Sentinel,
Fitzpatrick, Slack, Usdan and certain other parties pursuant to the Purchase
Agreement.

          "Offered Shares" has the meaning given thereto in Section 6(a).

          "Other Stockholders" means, with respect to a Stockholder, all
Stockholders other than such Stockholder.

          "Ownership Ratio" means, as to a holder of Stockholder Shares at the
time of determination, the percentage obtained by dividing the number of shares
of Common Stock owned by such holder at such time on a fully diluted as if
converted basis, by the aggregate number of shares of Common Stock Deemed
Outstanding at such time.

          "Permitted Transferees" has the meaning given thereto in Section 4(c).

          "Person" means an individual, a partnership, a corporation, a limited
liability company, an association, a joint stock company, a trust, a joint
venture, an unincorporated organization or a governmental entity or any
department, agency or political subdivision thereof.

          "Preemptive Period" has the meaning given thereto in Section 6(a).

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          "Public Sale" means any sale of Stockholder Shares to the public
pursuant to an offering registered under the Securities Act or to the public
effected through a broker, dealer or market maker pursuant to the provisions of
Rule 144 (or any similar rule or rules then in effect) under the Securities Act.

          "Purchase Agreement" has the meaning given thereto in the preamble.

          "Sale Notice" has the meaning given thereto in Section 4(b).

          "Sale of the Company" means (i) a transaction or series of related
transactions closing contemporaneously (including by way of merger,
consolidation, or sale of equity) the result of which is that the holders of the
Common Stock immediately prior to such transaction(s) (on a fully diluted as if
converted basis) are after giving effect to such transaction(s) no longer, in
the aggregate, the "beneficial owners" (as such term is defined in Rule 13d-3
and Rule 13d-5 promulgated under the Securities Exchange Act), directly or
indirectly through one or more intermediaries, of more than 50% of the Common
Stock Deemed Outstanding, or (ii) the sale, lease, transfer, conveyance or other
disposition, in one or a series of related transactions closing
contemporaneously, of all or substantially all of the Company's assets
determined on a consolidated basis.

          "SEC" means the Securities and Exchange Commission.

          "Securities Act" means the Securities Act of 1933, as amended from
time to time.

          "Securities Exchange Act" means the Securities Exchange Act of 1934,
as amended.

          "Sentinel" has the meaning given thereto in the preamble.

          "Sentinel Directors" has the meaning given thereto in Section
2(a)(i)(A).

          "Sentinel Stockholder Shares" means all Stockholder Shares issued or
issuable to, or otherwise held by, Sentinel and its Affiliates. Any reference
herein to a "holders of a majority of the Sentinel Stockholder Shares", means
the holders of a majority of the Sentinel Stockholder Shares on a fully diluted
as if converted basis.

          "Series A-1 Stock" means the Convertible Preferred Stock, Series A-1,
of the Company, par value $0.000001 per share.

          "Series A-2 Stock" means the Convertible Preferred Stock, Series A-2,
of the Company, par value $0.000001 per share.

          "Series B Stock" means the Company's Series B Convertible Preferred
Stock, par value $0.000001 per share.

          "Slack" has the meaning given thereto in the preamble.

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          "Stock Option Plan" means any capital stock plan adopted by the
Company for the benefit of the Company's officers, employees, consultants,
agents or directors which has been or is approved by the Board of Directors,
including the Company's 2002 Stock Option Plan.

          "Stockholder" has the meaning given thereto in the preamble.

          "Stockholder Shares" means (i) any Common Stock, Series A-1 Stock,
Series A-2 Stock, Series B Stock or Warrants held by the Stockholders, (ii) any
Common Stock or Series A-2 Stock issuable upon conversion, exercise or exchange
of the securities referred to in clause (i) above, and (iii) any equity
securities of the Company issued or issuable directly or indirectly with respect
to the securities referred to in clauses (i) or (ii) above by way of stock
dividend or stock split or in connection with a combination of shares,
recapitalization, merger, consolidation or other reorganization. As to any
particular shares constituting Stockholder Shares, such shares will cease to be
Stockholder Shares when they have been sold in a Public Sale or an Approved
Sale.

          "Sub Board" has the meaning given thereto in Section 2(a)(ii).

          "Subsidiary" means, with respect to any Person, any corporation,
partnership, association or other business entity of which (i) if a corporation,
a majority of the total voting power of shares of stock entitled (without regard
to the occurrence of any contingency) to vote in the election of directors,
managers or trustees thereof is at the time owned or controlled, directly or
indirectly, by that Person or one or more of the other Subsidiaries of that
Person or a combination thereof, or (ii) if a partnership, association or other
business entity, a majority of the partnership or other similar ownership
interest thereof is at the time owned or controlled, directly or indirectly, by
any Person or one or more Subsidiaries of that Person or a combination thereof.
For purposes hereof, a Person or Persons shall be deemed to have a majority
ownership interest in a partnership, association or other business entity if
such Person or Persons shall be allocated a majority of partnership, association
or other business entity gains or losses or shall be or control the managing
director or a general partner of such partnership, association or other business
entity.

          "Transaction Documents" means the Purchase Agreement and the other
documents expressly contemplated thereby.

          "Transfer" has the meaning given thereto in Section 4(a).

          "Transferring Stockholder" has the meaning given thereto in Section
4(b).

          "Voting Securities" means securities of the Company ordinarily having
the power to vote for the election of directors of the Company; provided that
when the term "Voting Securities" is used with respect to any other Person it
means the capital stock or other interests of any class or kind ordinarily
having the power to vote for the election of directors or other members of the
governing body of such Person.

          "Usdan" has the meaning given thereto in the preamble.

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          "Warrants" means the warrants to purchase Series A-2 Stock issued to
or held by GE.

          2.     Voting Matters.

          (a)    To the extent permitted by law, each Stockholder shall vote all
voting securities of the Company over which such Stockholder has voting control,
and shall take all other necessary or desirable actions within such
Stockholder's control (whether in such Stockholder's capacity as a stockholder,
director, member of a board committee or officer of the Company or otherwise,
and including, without limitation, attendance at meetings in person or by proxy
for purposes of obtaining a quorum and execution of written consents in lieu of
meetings), and the Company shall take all necessary and desirable actions within
its control (including, without limitation, calling special Board and
stockholder meetings), so that:

          (i)    the authorized number of directors on the Board shall be
established at 7 persons; provided that the Board shall be enlarged upon the
affirmative written consent of the holders of a majority of the Sentinel
Stockholder Shares;

          (ii)   the following persons shall be elected to the Board:

                 (A) so long as Sentinel and its Affiliates own at least a
majority of the Sentinel Stockholder Shares outstanding on the date of this
Agreement, 4 persons designated by holders of a majority of the Sentinel
Stockholder Shares, who shall initially include David S. Lobel, Fitzpatrick,
Paul F. Murphy and Edward Kuntz; provided that if the Board is enlarged as
described in clause (i) above, the holders of a majority of the Sentinel
Stockholder Shares shall be permitted to designate the smallest number of
directors greater than 4 which would be a majority of the Board (i.e., 5 of 8, 5
of 9, 6 of 10) (all such persons designated pursuant to this clause (A), the
"Sentinel Directors");

                 (B) so long as GE, Midwest, Usdan and their Affiliates own at
least a majority of the Non-Sentinel Stockholder Shares outstanding on the date
of this Agreement, 2 persons designated by holders of a majority of the
Non-Sentinel Stockholder Shares; provided that if the Board is enlarged as
described in clause (i) above, the holders of a majority of the Non-Sentinel
Stockholder Shares shall be permitted to designate such number of directors as
are on the enlarged Board and not designated pursuant to clause (A) above and
clause (C) below (all such persons designated pursuant to this clause (B), the
"Non-Sentinel Directors");

                 (C) the Chief Executive Officer of the Company;

          (iii)  the Company shall cause the board of directors of each
Subsidiary of the Company (each a "Sub Board") to be comprised of the same
members as are on the Board;

          (iv)   except as otherwise required by law, two Sentinel Directors and
one Non-Sentinel Director, who shall be appointed by the holders of a majority
of the Sentinel Stockholder Shares and the holders of a majority of the
Non-Sentinel Stockholder Shares respectively (and who may appoint different
directors for each such committee), shall be appointed to the executive
committee, nominating committee, compensation committee and audit committee of
the Board (each of which shall have no more than three (3) members) and such

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other committees of the Board and of the board of directors of each Subsidiary
of the Company as requested by the holders of a majority of the Sentinel
Stockholder Shares; notwithstanding the foregoing, the Non-Sentinel Directors
and the CEO shall be appointed to a committee of the Board which committee shall
be delegated the sole and exclusive power and authority to determine (x) when
and if the debt, or any portion thereof, represented by the Notes is prepaid
pursuant to Section 3 of the Notes, and (y) any debt financing arrangements of
the Company necessary to acquire the funds to affect such prepayment, subject to
any restrictions on such financing set forth in Section 3 of the Notes and
provided that the aggregate proceeds of such debt financing arrangement do not
materially exceed the amount necessary for such prepayment;

          (v)    Sentinel Directors shall be removed from the Board or any
committee thereof (without cause) at the written request of the holders of a
majority of the Sentinel Stockholder Shares, but only upon such written request
and under no other circumstances, except as required by law, and Non-Sentinel
Directors shall be removed from the Board or any committee thereof (without
cause) at the written request of the holders of a majority of the Non-Sentinel
Stockholder Shares, but only upon such written request and under no other
circumstances, except as required by law;

          (vi)   in the event that any Sentinel Director for any reason ceases
to serve as a member of the Board or any committee thereof during such
representative's term of office, the resulting vacancy on the Board or committee
shall be filled by a representative designated by the holders of a majority of
the Sentinel Stockholder Shares and in the event that any Non-Sentinel Director
for any reason ceases to serve as a member of the Board or any committee thereof
during such representative's term of office, the resulting vacancy on the Board
or committee shall be filled by a representative designated by the holders of a
majority of the Non-Sentinel Stockholder Shares.

          (b)    In addition, so long as Sentinel and its Affiliates own at
least a majority of the Sentinel Stockholder Shares outstanding on the date of
this Agreement, the Company shall not, without the affirmative vote of the
holders of a majority of the outstanding Sentinel Stockholder Shares: (i) alter
or change the preferences, rights or powers of the Series B Stock, (ii) create,
authorize or issue any capital stock that ranks prior (whether with respect to
dividends, redemption or upon liquidation, dissolution, winding up or otherwise)
to or pari passu with the Series B Stock, (iii) increase the authorized number
of shares of Series B Stock, (iv) create, authorize or issue any capital stock
of the Company or any Subsidiary of the Company or any security convertible
into, exchangeable for, or that otherwise gives the holder the right to obtain,
capital stock of the Company or any Subsidiary of the Company (other than (x)
the shares of Common Stock or Series A-2 Stock issuable upon conversion,
exercise or exchange of the Stockholder Shares outstanding as of the date
hereof, or (y) options to acquire shares of Common Stock issued to employees,
officers, directors, consultants and agents of the Company, or shares of Common
Stock issuable pursuant to the exercise of such options, pursuant to the Stock
Option Plan, (v) declare or pay a dividend with respect to any Stockholder
Shares, (vi) amend the Company's Certificate of Incorporation or Bylaws except
as specifically contemplated in the Purchase Agreement, (vii) materially amend
the terms of the Company's senior credit facility entered into on the date
hereof, except as required to prepay the debt represented by the Notes pursuant
to Section 3 of the Notes, (viii) effect a Change of Control, (ix) create or
incur, or permit any Subsidiary of the Company to create or incur, Indebtedness
other than Indebtedness

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existing on the date hereof, Indebtedness approved in an annual budget approved
by the Board and other Indebtedness not to exceed $1,000,000 in the aggregate,
except as required to prepay the debt represented by the Notes pursuant to
Section 3 of the Notes, (x) effect a voluntary liquidation, dissolution or
winding up of the Company, (xi) acquire, or permit any Subsidiary of the Company
to acquire, any interest in any company or business (whether by a purchase of
assets, purchase of stock, merger or otherwise), or enter into any joint venture
involving the operation of a business, or make any investment in any company or
business, (xii) enter into, amend, modify or supplement, or permit any
Subsidiary of the Company to enter into, amend, modify or supplement, any
agreement, transaction, commitment or arrangement with any of its or any
Subsidiary's officers, directors, or stockholders holding at least 2% of the
Common Stock, with any Affiliate or with any Immediate Family of any such
individual or with any entity in which any such Person or individual owns a
beneficial interest, except for employment arrangements and benefit programs
approved by the Board or the applicable board of directors of the Company's
Subsidiaries or authorized committees thereof, (xiii) become subject to, or
permit any of its Subsidiaries to become subject to, (including by way of
amendment to or modification of) any agreement or instrument which by its terms
would (under any circumstances) restrict the Company's right to comply (but not
the Company's ability to comply) with these terms of the Series B Stock, or
(xiv) terminate the employment of any senior executive.

          (c)    The Company shall pay the reasonable out-of-pocket expenses
incurred by each director in connection with attending the meetings of the Board
or any Sub Board and any committee thereof.

          (d)    In the event that any provision of the Bylaws or Certificate of
Incorporation is inconsistent with any provision of this Section 2, the
Stockholders shall take such action as may be necessary to amend any such
provision in the Bylaws or the Certificate of Incorporation to remedy such
inconsistency.

          (e)    The Company hereby agrees that as long as GE owns a majority of
the Stockholder Shares held by it on the date of this Agreement and as long as
Midwest owns a majority of the Stockholder Shares held by it on the date of this
Agreement: (i) each of GE and Midwest, as the case may be, will be given
reasonable and adequate notice of each meeting of the Board, which shall be no
less notice than that given to a majority of the members of the Board: (ii) each
of GE and Midwest, as the case may be, shall each have the right to have one
observer attend each such meeting; (iii) each of GE and Midwest, as the case may
be, shall be entitled to observe such meeting by phone or other method whereby
they can hear all of the participants in the meeting; (iv) each of GE and
Midwest, as the case may be, shall be entitled to receive all materials provided
to the members of the Board of Directors in connection with such meeting; and
(v) if the Board intends to take any action pursuant to a written consent, each
of GE and Midwest, as the case may be, will be forwarded copies of such written
consents no later than the date copies are distributed to the members of the
Board.

          (f)    Notwithstanding anything herein to the contrary, nothing
contained in this Agreement shall (i) affect, limit or impair the rights and/or
remedies of GE in its capacity as a lender to the Company or any of its
Subsidiaries pursuant to any agreement under which the Company or any of its
Subsidiaries has or have borrowed money or (ii) be deemed otherwise to

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require or cause GE to take or omit to take any action in its capacity as a
lender or any other holder of debt of the Company or any of its Subsidiaries.

          3.     Conflicting Agreements. Each Stockholder represents that such
Stockholder has not granted and is not a party to any proxy, voting trust or
other agreement which is inconsistent with or conflicts with the provisions of
this Agreement, and no holder of Stockholder Shares shall grant any proxy or
become party to any voting trust or other agreement which is inconsistent with
or conflicts with the provisions of this Agreement.

          4.     Restrictions on Transfer of Stockholder Shares.

          (a)    Transfer of Stockholder Shares. No holder of Stockholder Shares
shall sell, transfer, assign, pledge or otherwise dispose (a "Transfer") of
(whether with or without consideration and whether voluntarily or involuntarily
or by operation of law) any interest in such holder's Stockholder Shares, except
(i) pursuant to the provisions of Section 4(b) below, (ii) in a Public Sale,
(iii) pursuant to an Approved Sale, or (iv) to a Permitted Transferee.

          (b)    Tag Along Rights. At least 30 days prior to any Transfer of
Stockholder Shares by a Stockholder (other than those Transfers described in
clauses (ii), (iii) and (iv) of Section 4(a) above) (the "Transferring
Stockholder"), the Transferring Stockholder shall deliver a written notice (the
"Sale Notice") to the Company, which shall promptly deliver the Sale Notice to
the Other Stockholders, specifying in reasonable detail the identity of the
prospective transferee(s) and the terms and conditions of the Transfer. The
Other Stockholders may elect to participate in the contemplated Transfer by
delivering written notice to Sentinel within 10 days after delivery of the Sale
Notice. If any Other Stockholders have elected to participate in such Transfer,
each of the Transferring Stockholder and such Other Stockholders shall be
entitled to sell in the contemplated Transfer, at the same price and on the same
terms (provided that adequate provision shall be made to account for any
exercise or conversion prices payable by any Stockholder with respect to any
rights to acquire Stockholder Shares), a number of shares of Common Stock (or
Stockholder Shares exercisable for or convertible into such number) equal to the
product of (i) the quotient determined by dividing the number of shares of
Common Stock owned by such Stockholder on a fully diluted as if converted basis
by the aggregate number of shares of Common Stock owned by the Stockholders
participating in such Transfer on a fully diluted as if converted basis, and
(ii) the aggregate number of shares of Common Stock to be sold to the proposed
transferee in the contemplated Transfer on a fully diluted as if converted
basis. Upon consummation of a Transfer contemplated by this clause (b), each
Stockholder shall receive in exchange for the Stockholder Shares Transferred by
such Stockholder pursuant to such Transfer, its pro rata portion of the
aggregate consideration received pursuant to such Transfer based upon the
percentage of all Stockholder Shares on a fully diluted as if converted basis
Transferred pursuant to such Transfer held by such Stockholder. All Stockholders
will bear their pro rata share (based upon the consideration received pursuant
to the Transfer) of the reasonable costs of such Transfer to the extent such
costs are incurred for the benefit of all participating Stockholders and are not
otherwise paid by the Company or the acquiring party. Costs incurred by any
Stockholder on its own behalf will not be considered costs of the transaction
hereunder.

          (c)    Permitted Transfers. The restrictions contained in Sections
4(a) and 4(b) shall not apply with respect to any Transfer of Stockholder Shares
by any Stockholder (i) to

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another Stockholder who is party to this Agreement, (ii) in the case of an
individual Stockholder, pursuant to applicable laws of descent and distribution
or to any member of such Stockholder's Family Group, or (iii) in the case of an
entity, (x) among its Affiliates, partners or employees, or consultants, or (y)
to any employee or director of the Company or any Affiliate of the Company. All
transferees permitted under this Section 4(c) are collectively referred to
herein as "Permitted Transferees."

          (d)    Provisions of General Applicability. Each transaction of
purchase and sale of Stockholder Shares pursuant to this Agreement shall be
completed by delivery of the certificates representing such shares endorsed in
blank and by actual registration of the transfer of such shares on the books of
the Company upon payment of the purchase price to the seller of such shares.

          5.     Sale of the Company.

          (a)    In the event of an Approved Sale, each Stockholder will (i)
consent to and raise no objections against the Approved Sale or the process
pursuant to which the Approved Sale was arranged, (ii) waive any dissenter's
rights and other similar rights, and (iii) if the Approved Sale is structured as
a sale of securities, each Stockholder will agree to sell its Stockholder Shares
(and any other capital stock of the Company) on the terms and conditions of the
Approved Sale; provided that it is acknowledged that each Stockholder retains
his, her or its right to object to the Approved Sale on the basis that the
members of the Board are in breach of their fiduciary duty as members of the
Board.

          (b)    The obligations of each Stockholder under this Section 5 are
subject to the satisfaction of the following conditions: (i) upon consummation
of an Approved Sale, each Stockholder shall receive in exchange for the
Stockholder Shares (and any other capital stock of the Company) held by such
Stockholder the same portion of the aggregate consideration from such sale or
exchange that such Stockholder would have received if such aggregate
consideration had been distributed by the Company in complete liquidation
pursuant to the rights and preferences set forth in the Certificate of
Incorporation, (ii) if the holders of a class or series of capital stock of the
Company are given an option as to the form of consideration to be received, all
holders of shares of such class or series of capital stock shall be given the
same option (excluding any options or similar securities given to an executive
of the Company as an incentive to remain an employee following the Approved
Sale; provided that such incentive compensation is reasonable under the
circumstances and is negotiated by the Company, such executive and the
applicable purchaser in good faith without the intention of allocating incentive
consideration to an executive in excess of what such purchaser would normally
allocate in lieu of paying a larger purchase price for the Company), (iii) each
holder of then currently exercisable rights to acquire Stockholder Shares shall
be given no less than ten (10) days notice to exercise such rights prior to the
consummation of the Approved Sale and participate in such sale as a holder of
such Stockholder Shares, and (iv) with respect to any Approved Sale that implies
an equity value of less than the aggregate "Liquidation Payment" of the
outstanding Series B Stock as of the date of consummation of the Approved Sale,
the Company shall receive a customary fairness opinion with respect to such
Approved Sale from an investment bank reasonably acceptable to the holders of a
majority of the Sentinel Stockholder Shares and the holders of a majority of the
Non-Sentinel Stockholder Shares.

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          (c)    All Stockholders will bear their pro rata share (based upon the
consideration received pursuant to the Approved Sale) of the reasonable costs of
an Approved Sale to the extent such costs are incurred for the benefit of all
Stockholders and are not otherwise paid by the Company or the acquiring party.
Costs incurred by any Stockholder on its own behalf will not be considered costs
of the transaction hereunder.

          (d)    Sentinel and the Company covenant that so long as Sentinel
holds at least a majority of the Sentinel Stockholder Shares outstanding on the
date of this Agreement, they will give GE and Midwest prompt written notice of
the commencement of a process intended to consummate in a Sale of the Company;
provided that GE shall be entitled to such notice only so long as GE owns a
majority of the Stockholder Shares held by it on the date of this Agreement and
Midwest shall be entitled to such notice only so long as Midwest owns a majority
of the Stockholder Shares held by it on the date of this Agreement.

          (e)    Each Stockholder will take all necessary and desirable actions
as directed by the Board and the Approving Stockholders in connection with the
consummation of any Approved Sale, including without limitation executing the
applicable purchase agreement and granting identical indemnification rights;
provided that (i) each Stockholder shall only be severally obligated to join on
a pro rata basis (based on such Stockholder's share of the aggregate proceeds
paid with respect to his or its interest) in any indemnification obligation
agreed to in connection with such Approved Sale, other than any such obligations
that relate to breaches of covenants by such Stockholder or breaches of
representations specifically concerning such Stockholder (i.e. such
Stockholder's ownership of shares, title, authority, investment intent, etc.),
for which such Stockholder shall be fully liable, and (ii) each Stockholder's
indemnity obligation shall be limited to an amount equal to the net cash
proceeds paid to such Stockholder in connection with such Approved Sale (other
than obligations resulting from breaches of covenants by such Stockholder or
breaches of representations specifically concerning such Stockholder, as to
which no limitation shall apply).

          6.     Pre-emptive Rights.

          (a)    Subject to Section 6(b) below, if the Company proposes to issue
any shares of Common Stock or any Common Stock Equivalents, in each case after
the date of this Agreement, the Company will offer to sell to each Stockholder a
number of such securities ("Offered Shares") so that the Ownership Ratio for
such holder immediately after the issuance of such securities (and assuming the
purchase of such Offered Shares) would be equal to the Ownership Ratio for such
holder immediately prior to such issuance of securities. The Company shall give
each such holder at least twenty (20) days prior written notice of any proposed
issuance, which notice shall disclose in reasonable detail the proposed terms
and conditions of such issuance (the "Issuance Notice"). Each such Stockholder
will be entitled to purchase such securities at the same price, on the same
terms (including, if more than one type of security is issued, the same
proportionate mix of such securities), and at the same time as the securities
are issued by delivery of irrevocable written notice (the "Election Notice") to
the Company of such election within ten (10) days after delivery of the Issuance
Notice (the "Preemptive Period"). If any such Stockholder has elected to
purchase any Offered Shares, the sale of such shares shall be consummated as
soon as practical after the delivery of the Election Notice. To the extent such
Stockholders do not elect to, or are not entitled to purchase all of the Offered
Shares, then the

                                     - 11 -

<PAGE>

Company may issue the remaining Offered Shares at a price and on terms no more
favorable to the transferee(s) thereof specified in the Issuance Notice during
the 120-day period following the Preemptive Period.

          (b)    The rights contained in Section 6(a) shall not apply to the
issuance of Common Stock or Common Stock Equivalents: (i) as a stock dividend or
upon any subdivision or stock split of the outstanding shares of Common Stock;
(ii) upon exercise of any warrants or options outstanding as of the date of this
Agreement; (iii) upon exercise or conversion of any Stockholder Shares; (iv) to
officers, directors, consultants and other employees or agents of the Company;
(v) pursuant to the acquisition of another business entity by the Company by
merger, purchase of substantially all of the assets of such entity, or other
transaction whereby the Company acquires not less than a majority of the voting
power of such entity, or (vi) if such issuance is designated in writing by the
holders of a majority of the Sentinel Stockholder Shares as an issuance which
will not be subject to Section 6(a), provided no Common Stock or Common Stock
Equivalents are issued to such holders or their Affiliates pursuant to such
issuance.

          7.     Legend. In addition to any legend required by any other
agreement, each certificate evidencing Stockholder Shares and each certificate
issued in exchange for or upon the transfer of any Stockholder Shares (if such
shares remain Stockholder Shares as defined herein after such transfer) shall be
stamped or otherwise imprinted with a legend in substantially the following
form:

          "THE SECURITIES REPRESENTED BY THIS CERTIFICATE WERE
          ORIGINALLY ISSUED ON __________, AND HAVE NOT BEEN
          REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED. THE
          SECURITIES REPRESENTED BY THIS CERTIFICATE AND ANY INTEREST
          THEREIN MAY NOT BE SOLD, TRANSFERRED, PLEDGED, HYPOTHECATED
          OR OTHERWISE DISPOSED OF, EXCEPT PURSUANT TO (i) AN
          EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF
          1933, AS AMENDED, AND APPLICABLE STATE SECURITIES LAWS OR
          (ii) AN EXEMPTION FROM REGISTRATION UNDER SUCH ACTS. THE
          TRANSFER OF THE SECURITIES REPRESENTED BY THIS CERTIFICATE
          IS SUBJECT TO A STOCKHOLDERS AGREEMENT DATED AS OF MAY 15,
          2003, BY AND AMONG THE ISSUER OF SUCH SECURITIES (THE
          "COMPANY") AND CERTAIN OF THE COMPANY'S STOCKHOLDERS. A COPY
          OF SUCH STOCKHOLDERS AGREEMENT WILL BE FURNISHED WITHOUT
          CHARGE BY THE COMPANY TO THE HOLDER HEREOF UPON WRITTEN
          REQUEST."

The Company shall imprint such legend on certificates evidencing Stockholder
Shares outstanding prior to the date hereof. The legend set forth above shall be
removed from the certificates evidencing any shares which cease to be
Stockholder Shares.

                                     - 12 -

<PAGE>

          8.     Transfers in Violation of Agreement. Any Transfer or attempted
Transfer of any Stockholder Shares in violation of any provision of this
Agreement shall be null and void, and the Company shall not record such Transfer
on its books or treat any purported transferee of such Stockholder Shares as the
owner of such shares for any purpose.

          9.     Transfer of Stockholder Shares.

          (a)    In connection with the Transfer of any Stockholder Shares other
than a Transfer to the public pursuant to an offering registered under the
Securities Act, the holder thereof shall deliver written notice to the Company
describing in reasonable detail the Transfer or proposed Transfer, together with
an opinion of counsel reasonably acceptable to the Company to the effect that
such Transfer of Stockholder Shares may be effected without registration of such
Stockholder Shares under the Securities Act (provided that no such opinion shall
be necessary in conjunction with a Transfer to a Permitted Transferee). No
Transfer of Stockholder Shares (including a Transfer to a Permitted Transferee)
shall be permitted unless and until the prospective transferee agrees to become
a party to this Agreement and be bound by all the terms and conditions hereof by
executing and delivering to the Company, a Joinder Agreement in the form
attached hereto as Exhibit A.

          (b)    Upon the request of a holder of Stockholder Shares, the Company
shall promptly supply to such Person or its prospective transferees all
information regarding the Company required to be delivered in connection with a
Transfer pursuant to Rule 144A (or any similar rule or rules then in effect) of
the SEC.

          10.    Conversion. Each Stockholder agrees that if at any time a
majority of the Series B Stock then outstanding is converted into Common Stock,
such Stockholder will immediately convert all Series A-1 Stock, Series A-2 Stock
and Series B Stock that such Stockholder then holds into Common Stock.

          11.    Amendment; Waiver and Termination. Except as otherwise provided
herein, no amendment, waiver or termination of any provision of this Agreement
shall be effective against the Company or the Stockholders unless such
amendment, waiver or termination is approved in writing by the Company, the
holders of a majority of the Sentinel Stockholder Shares, and the holders of a
majority of the Non-Sentinel Stockholder Shares; provided, however, no amendment
or waiver can be effected if, by its terms, such amendment, modification,
supplement or waiver adversely affects one Stockholder without having the same
relative adverse effect on all Stockholders without the prior written consent of
such adversely affected Stockholder. The failure of any party to enforce any of
the provisions of this Agreement shall in no way be construed as a waiver of
such provisions and shall not affect the right of such party thereafter to
enforce each and every provision of this Agreement in accordance with its terms.

          12.    Severability. Whenever possible, each provision of this
Agreement shall be interpreted in such manner as to be effective and valid under
applicable law, but if any provision of this Agreement is held to be invalid,
illegal or unenforceable in any respect under any applicable law or rule in any
jurisdiction, such invalidity, illegality or unenforceability shall not affect
any other provision or any other jurisdiction, but this Agreement shall be
reformed,

                                     - 13 -

<PAGE>

construed and enforced in such jurisdiction as if such invalid, illegal or
unenforceable provision had never been contained herein.

          13.    Entire Agreement. Except as otherwise expressly set forth
herein, this document and the other Transaction Documents embody the complete
agreement and understanding among the parties hereto with respect to the subject
matter hereof and supersede and preempt any prior understandings, agreements or
representations by or among the parties, written or oral, which may have related
to the subject matter hereof in any way.

          14.    Successors and Assigns. Except as otherwise provided herein,
this Agreement shall bind and inure to the benefit of and be enforceable by the
Company and its successors and assigns and the Stockholders and any subsequent
holders of Stockholder Shares and the respective permitted successors and
assigns of each of them, so long as they hold Stockholder Shares.

          15.    Counterparts. This Agreement may be executed in separate
counterparts each of which shall be an original and all of which taken together
shall constitute one and the same agreement.

          16.    Remedies. The parties hereto shall be entitled to enforce their
rights under this Agreement specifically to recover damages by reason of any
breach of any provision of this Agreement and to exercise all other rights
existing in their favor. The parties hereto agree and acknowledge that money
damages may not be an adequate remedy for any breach of the provisions of this
Agreement and that the Company, and may in its sole discretion apply to any
court of law or equity of competent jurisdiction for specific performance and/or
injunctive relief (without posting a bond or other security) in order to enforce
or prevent any violation of the provisions of this Agreement.

          17.    Notices. All notices, demands or other communications to be
given or delivered under or by reason of the provisions of this Agreement will
be in writing and will be deemed to have been given when delivered personally,
mailed by certified or registered mail, return receipt requested and postage
prepaid, or sent via a nationally recognized overnight courier, or sent via
facsimile to the recipient accompanied by a certified or registered mailing.
Such notices, demands and other communications will be sent to the Company at
its executive office, and to each Stockholder at the address set forth for such
Stockholder in the Company's records.

          18.    GOVERNING LAW. ALL QUESTIONS CONCERNING THE CONSTRUCTION,
VALIDITY AND INTERPRETATION OF THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED
IN ACCORDANCE WITH THE DOMESTIC LAWS OF THE STATE OF NEW YORK, WITHOUT GIVING
EFFECT TO ANY CHOICE OF LAW OR CONFLICT OF LAW PROVISION OR RULE (WHETHER OF THE
STATE OF NEW YORK OR ANY OTHER JURISDICTION) THAT WOULD CAUSE THE APPLICATION OF
THE LAWS OF ANY JURISDICTION OTHER THAN THE STATE OF NEW YORK.

                                     - 14 -

<PAGE>

          19.    Descriptive Headings. The descriptive headings of this
Agreement are inserted for convenience only and do not constitute a part of this
Agreement.

          20.    Waiver of Jury Trial. Each of the parties hereto waives any
right it may have to trial by jury in respect of any litigation based on,
arising out of, under or in connection with this Agreement or any course of
conduct, course of dealing, verbal or written statement or action of any party
hereto.

                                    * * * * *

                                     - 15 -

<PAGE>

          IN WITNESS WHEREOF, the parties hereto have executed this Stockholders
Agreement as of the date first above written.

                                       CASTLE DENTAL CENTERS, INC.

                                       By:
                                          --------------------------------------
                                          Name:
                                          Title:

                                       SENTINEL CAPITAL PARTNERS II, L.P.

                                       By   Sentinel Partners II, L.P.
                                       Its: General Partner

                                       By:  Sentinel Managing Company II, LLC
                                       Its: General Partner

                                       By:
                                          --------------------------------------
                                          Name:
                                          Title:

                                       MIDWEST MEZZANINE FUND II, L.P.

                                       By   ABN AMRO Mezzanine Management II,
                                            L.P.
                                       Its: General Partner

                                       By:  ABN AMRO Mezzanine Management II,
                                            INC.
                                       Its: General Partner

                                       By:
                                          --------------------------------------
                                          Name:  Paul Kreie
                                          Title: Vice President

                                       GENERAL ELECTRIC CAPITAL CORPORATION

                                       By:
                                          --------------------------------------
                                          Name:
                                          Title:

                                     - 16 -

<PAGE>

                                          --------------------------------------
                                          JAMES M. USDAN

                                          --------------------------------------
                                          THOMAS FITZPATRICK

                                          --------------------------------------
                                          JOHN M. SLACK

                                     - 17 -

<PAGE>

                                    EXHIBIT A

                               FORM OF JOINDER TO
                             STOCKHOLDERS AGREEMENT

          THIS JOINDER to the Stockholders Agreement, dated as of May 15, 2003
by and among Castle Dental Centers, Inc., a Delaware corporation (the
"Company"), and certain stockholders of the Company (the "Agreement"), is made
and entered into as of _________ by and between the Company and
_________________ ("Holder"). Capitalized terms used herein but not otherwise
defined shall have the meanings set forth in the Agreement.

          WHEREAS, Holder has acquired certain shares of [________________]
("Holder Stock"), and the Agreement and the Company requires Holder, as a holder
of Holder Stock, to become a party to the Agreement, and Holder agrees to do so
in accordance with the terms hereof.

          NOW, THEREFORE, in consideration of the mutual covenants contained
herein and other good and valuable consideration, the receipt and sufficiency of
which are hereby acknowledged, the parties to this Joinder hereby agree as
follows:

          1.     Agreement to be Bound. Holder hereby agrees that upon execution
of this Joinder, it shall become a party to the Agreement and shall be fully
bound by, and subject to, all of the covenants, terms and conditions of the
Agreement as though an original party thereto and shall be deemed a Stockholder
for all purposes thereof. In addition, Holder hereby agrees that all Holder
Stock held by Holder shall be deemed Stockholder Shares for all purposes of the
Agreement.

          2.     Successors and Assigns. Except as otherwise provided herein,
this Joinder shall bind and inure to the benefit of and be enforceable by the
Company, the Stockholders and their successors and assigns and Holder and any
subsequent holders of Holder Stock and the respective successors and assigns of
each of them, so long as they hold any shares of Holder Stock.

          3.     Counterparts. This Joinder may be executed in separate
counterparts each of which shall be an original and all of which taken together
shall constitute one and the same agreement.

          4.     Governing Law. ALL QUESTIONS CONCERNING THE CONSTRUCTION,
VALIDITY AND INTERPRETATION OF THIS JOINDER SHALL BE GOVERNED BY AND CONSTRUED
IN ACCORDANCE WITH THE DOMESTIC LAWS OF THE STATE OF NEW YORK, WITHOUT GIVING
EFFECT TO ANY CHOICE OF LAW OR CONFLICT OF LAW PROVISION OR RULE (WHETHER OF THE
STATE OF NEW YORK OR ANY OTHER JURISDICTION) THAT WOULD CAUSE THE APPLICATION OF
THE LAWS OF ANY JURISDICTION OTHER THAN THE STATE OF NEW YORK.

                                     - 18 -

<PAGE>

          5.     Descriptive Headings. The descriptive headings of this Joinder
are inserted for convenience only and do not constitute a part of this Joinder.

                                    * * * * *

                                     - 19 -

<PAGE>

          IN WITNESS WHEREOF, the parties hereto have executed this Joinder as
of the date first above written.

                                       CASTLE DENTAL CENTERS, INC.

                                       By:
                                          ------------------------------------
                                       Name:
                                       Title:

                                       [HOLDER]

                                       By:
                                          ------------------------------------

                                     - 20 -<PAGE>

                                                                    EXHIBIT 10.5

                          SUBORDINATED PROMISSORY NOTE

This instrument and the rights and obligations evidenced hereby are subordinate
in the manner and to the extent set forth in that certain Subordination and
Intercreditor Agreement (the "Subordination Agreement") dated as of May 15, 2003
by and among Sentinel Capital Partners II, L.P., a Delaware limited partnership,
Castle Dental Centers, Inc., a Delaware corporation (the "Company") and General
Electric Capital Corporation, a Delaware Corporation, as Agent ("Agent"), to the
indebtedness (including interest) owed by the Company pursuant to that certain
Credit Agreement dated as of May 15, 2003 by and among the Company, Agent and
the lenders from time to time party thereto, as such Credit Agreement has been
and hereafter may be amended, restated, supplemented or otherwise modified from
time to time and to indebtedness refinancing the indebtedness under that
agreement as contemplated by the Subordination Agreement; and each holder of
this instrument, by its acceptance hereof, irrevocably agrees to be bound by the
provisions of the Subordination Agreement.

THIS NOTE HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED,
OR THE SECURITIES LAWS OF ANY STATE AND MAY NOT BE SOLD, TRANSFERRED, OR
OTHERWISE DISPOSED OF EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT
UNDER SUCH ACT AND APPLICABLE STATE SECURITIES LAWS OR PURSUANT TO AN APPLICABLE
EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF SUCH ACT AND SUCH LAWS

                           CASTLE DENTAL CENTERS, INC.

                          SUBORDINATED PROMISSORY NOTE

$                                                             New York, New York
                                                                    May 15, 2003

          FOR VALUE RECEIVED, the undersigned, CASTLE DENTAL CENTERS, INC.
("Borrower"), a Delaware corporation, hereby promises to pay to the order of
_________________ or its registered assigns (the "Holder"), the principal sum of
$_______________ on May 15, 2008 (the "Maturity Date"), with interest thereon
from time to time as provided herein.

          1.     Purchase Agreement. This Subordinated Promissory Note (the
"Note") is issued by the Borrower on the date hereof pursuant to the Preferred
Stock and Subordinated Note Purchase Agreement (the "Purchase Agreement"), dated
as of May 15, 2003 by and between the Borrower, Sentinel Capital Partners II,
L.P. and certain other parties thereto, and is subject to the terms thereof.
This Note, together with all promissory notes issued pursuant to paragraph 5
hereof are hereinafter referred to as the "Notes." The Holder is entitled to the
benefits of this Note and the Purchase Agreement, as it relates to the Note, and
may enforce the agreements of the Borrower contained herein and therein and
exercise the remedies provided for hereby and thereby or otherwise

<PAGE>

available in respect hereto and thereto. Capitalized terms used herein without
definition are used herein with the meanings ascribed to such terms in the
Purchase Agreement.

          2.     Interest. The Borrower promises to pay interest ("Interest") on
the principal amount of this Note (including any Basic Interest or PIK Interest
added to the principal amount of this Note as provided in Sections 2(a) and 2(b)
below) at the rate of 20% per annum (the "Interest Rate"). Interest on this Note
shall accrue from and including the date of issuance through and until repayment
of the principal amount of this Note and payment of all Interest in full, and
shall be computed on the basis of a 360-day year of twelve 30-day months.
Interest shall be paid as follows:

          (a)    Basic Interest. The Borrower shall pay Interest ("Basic
Interest") on the principal amount of this Note at the rate of 10% per annum,
quarterly on each May 15, August 15, November 15 and February 15 of each year
or, if any such date shall not be a Business Day, on the next succeeding
Business Day to occur after such date (each date upon which Basic Interest shall
be so payable, an "Interest Payment Date"), beginning on August 15, 2003, by
wire transfer of immediately available funds to an account at a bank designated
in writing by the Holder; provided that if for any reason any portion of any
such payment of Basic Interest is not made on the applicable Interest Payment
Date, the amount of Basic Interest not so paid shall be added to the principal
amount of this Note until such time as such Basic Interest is paid. In the
absence of any such written designation, any such Interest payment shall be
deemed made on the date a check in the applicable amount payable to the order of
Holder is received by the Holder at its last address as reflected in Borrower's
note register; if no such address appears, then to such Holder in care of the
last address in such note register of any predecessor holder of this Note (or
its predecessor).

          (b)    PIK Interest. The Borrower shall pay Interest ("PIK Interest")
on the principal amount of this Note at a rate of 10% per annum, quarterly on
each Interest Payment Date, by adding an amount equal to the aggregate accrued
but unpaid PIK Interest as of such Interest Payment Date to the principal amount
of this Note.

          (c)    No Usurious Interest. In the event that any interest rate(s)
provided for in this Section 2 shall be determined to be unlawful, such interest
rate(s) shall be computed at the highest rate permitted by applicable law. Any
payment by the Borrower of any interest amount in excess of that permitted by
law shall be considered a mistake, with the excess being applied to the
principal amount of this Note without prepayment premium or penalty; if no such
principal amount is outstanding, such excess shall be returned to Borrower.

          3.     Optional Prepayment. Borrower shall be permitted at any time
and from time to time to prepay all or a portion of the principal and accrued
Interest on the Notes; provided that (A) such prepayments shall only be
permitted to be made with (i) cash on hand (provided such cash is not the
proceeds of a financing), and/or (ii) proceeds of senior secured debt (provided
that the terms of the pricing and interest rate of such debt shall not be less
favorable from the Borrower's perspective than those of the senior debt
represented by the credit facility entered into by the Company on May 15, 2003
and provided that no equity of the Borrower or instruments convertible or
exercisable for equity of the Borrower shall be issued to the applicable
lender(s) in partial consideration of the incurrence of such debt), (B) such
prepayments shall be in a minimum amount

                                        2

<PAGE>

of $1,000,000 (or such lesser amount of aggregate principal and Interest of the
Notes that is outstanding at such time), (C) such prepayments shall be applied
to accrued Interest first and then to outstanding principal, and (D) such
prepayments shall be made pro rata with respect to each Note based on the
aggregate principal and accrued Interest outstanding under each such Note.
Borrower shall also be permitted at any time and from time to time to prepay all
or a portion of the principal and accrued Interest on the Notes if Sentinel
consents in writing, provided that such prepayments shall be made pro rata with
respect to each Note based on the aggregate principal and accrued Interest
outstanding under each such Note.

          4.     Acceleration. On the earlier to occur of (i) the consummation
of a Change of Control, (ii) the Company's issuance after May 15, 2003 of equity
securities pursuant to a public offering registered pursuant to the Securities
Act of 1933 with a gross offering price equal to or exceeding the aggregate
principal and accrued Interest on the Notes, or (iii) a Liquidation Event, the
outstanding principal of and all accrued Interest on this Note shall
automatically become immediately due and payable, without presentment, demand,
protest or notice of any kind, all of which are hereby expressly waived.

     "Change of Control" means: (i) the sale, lease, transfer, conveyance or
other disposition, in one or a series of related transactions, of all or
substantially all the assets of the Borrower and its subsidiaries taken as a
whole to any "person" (as such term is used in Section 13(d)(3) of the
Securities Exchange Act of 1934, as amended (the "Exchange Act")), or (ii) the
consummation of any transaction (including any merger or consolidation) the
result of which is that any "person" (as defined above), other than Sentinel
Capital Partners II, L.P. and or its affiliates, becomes the beneficial owner
(as determined in accordance with Rules 13d-3 and 13d-5 under the Exchange Act
except that a person will be deemed to have beneficial ownership of all shares
that such person has the right to acquire, whether such right is exercisable
immediately or only after the passage of time), directly or indirectly, of more
than 50% of the Common Stock of the Company (on a fully diluted as if converted
basis).

     A "Liquidation Event" shall have occurred if (A) an involuntary proceeding
shall be commenced or an involuntary petition shall be filed in a court of
competent jurisdiction seeking (a) relief in respect of the Borrower or of a
substantial part of its property or assets, under Title 11 of the United States
Code, as now constituted or hereafter amended, or any other Federal or state
bankruptcy, insolvency, receivership or similar law, (b) the appointment of a
receiver, trustee, custodian, sequestrator, conservator or similar official for
the Borrower, or for a substantial part of its property or assets, or (c) the
winding up or liquidation of the Borrower; and such proceeding or petition shall
continue undismissed for 60 days, or an order or decree approving or ordering
any of the foregoing shall be entered, or (B) the Borrower shall (a) voluntarily
commence any proceeding or file any petition seeking relief under Title 11 of
the United States Code, as now constituted or hereafter amended, or any other
Federal or state bankruptcy, insolvency, receivership or similar law, (b) apply
for or consent to the appointment of a receiver, trustee, custodian,
sequestrator, conservator or similar official for the Borrower, or for a
substantial part of its property or assets, (c) make a general assignment for
the benefit of creditors, (d) become unable, admit in writing its inability or
fail generally to pay its debts as they become due or (e) take any action for
the purpose of effecting any of the foregoing.

                                        3

<PAGE>

          5.     Register; Assignment. The Borrower shall maintain a register
(the "Note Register") in its principal offices for the purpose of registering
the Note and any transfer or partial transfer thereof, which register shall
reflect and identify, at all times, the ownership of record of any interest in
the Note. Upon the issuance of this Note, the Borrower shall record the name and
address of the initial purchaser of this Note in the Note Register as the first
Holder. Upon surrender for registration of transfer or exchange of this Note at
the principal offices of the Borrower, the Borrower shall, at its expense,
execute and deliver one or more new Notes of like tenor and of denominations of
at least $1,000 (except as may be necessary to reflect any principal amount not
evenly divisible by $1,000) of a like aggregate principal amount, registered in
the name of the Holder or a transferee or transferees. Every Note surrendered
for registration of transfer or exchange shall be duly endorsed, or be
accompanied by written instrument of transfer duly executed by the Holder of
such Note or such holder's attorney duly authorized in writing. This Note may be
transferred or assigned, in whole or in part, by the Holder at any time.

          6.     Replacement of Note. On receipt by the Borrower of an affidavit
of an authorized representative of the Holder stating the circumstances of the
loss, theft, destruction or mutilation of this Note (and in the case of any such
mutilation, on surrender and cancellation of such Note), the Borrower, at its
expense, will promptly execute and deliver, in lieu thereof, a new Note of like
tenor. If required by the Borrower, such Holder must provide indemnity
sufficient in the reasonable judgment of the Borrower to protect the Borrower
from any loss which they may suffer if a lost, stolen or destroyed Note is
replaced.

          7.     Covenants Bind Successors and Assigns. All the covenants,
stipulations, promises and agreements in this Note contained by or on behalf of
the Borrower shall bind its successors and assigns, whether so expressed or not.

          8.     Notices. All notices, demands and other communications provided
for or permitted hereunder shall be made in writing and shall be by registered
or certified first-class mail, return receipt requested, telecopier (with
receipt confirmed), courier service or personal delivery at the addresses set
forth in the Company's records. All such notices and communications shall be
deemed to have been duly given when: delivered by hand, if personally delivered;
when delivered by courier, if delivered by commercial overnight courier service;
if mailed, five Business Days after being deposited in the mail, postage
prepaid; or if telecopied, when receipt is acknowledged.

          9.     Amendment. Amendments and modifications of the Notes may be
made only pursuant to a writing signed by the Borrower and holders of Notes
representing a majority of the aggregate outstanding principal represented by
the Notes at the time of such amendment or modification.

          10.    GOVERNING LAW. THIS AGREEMENT SHALL BE GOVERNED BY, CONSTRUED
IN ACCORDANCE WITH, AND ENFORCED UNDER, THE LAW OF THE STATE OF NEW YORK
APPLICABLE TO AGREEMENTS OR INSTRUMENTS ENTERED INTO AND PERFORMED ENTIRELY
WITHIN SUCH STATE.

                                        4

<PAGE>

          11.    Severability. If any one or more of the provisions contained
herein, or the application thereof in any circumstance, is held invalid, illegal
or unenforceable in any respect for any reason, the validity, legality and
enforceability of any such provision in every other respect and of the remaining
provisions hereof shall not be in any way impaired, unless the provisions held
invalid, illegal or unenforceable shall substantially impair the benefits of the
remaining provisions hereof.

          12.    Headings. The headings in this Note are for convenience of
reference only and shall not limit or otherwise affect the meaning hereof.

                                       CASTLE DENTAL CENTERS, INC.

                                       By:
                                          --------------------------------------
                                          Name:
                                          Title:

                [SIGNATURE PAGE TO SUBORDINATED PROMISSORY NOTE]

                                        5

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00052-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00052-of-00352.parquet"}]]