Document:

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                                                                    Exhibit 10.5

                          CONVERTIBLE SUBORDINATED NOTE

NEITHER THIS NOTE NOR THE COMMON STOCK ISSUABLE UPON CONVERSION HEREOF HAS BEEN
REGISTERED UNDER THE UNITED STATES SECURITIES ACT OF 1933, AS AMENDED, NOR THE
SECURITIES LAWS OF ANY STATE. NEITHER THIS NOTE NOR THE COMMON STOCK ISSUABLE
UPON CONVERSION HEREOF MAY BE SOLD, PLEDGED, HYPOTHECATED OR OTHERWISE
TRANSFERRED AT ANY TIME, EXCEPT UPON (1) SUCH REGISTRATION, OR (2) DELIVERY TO
THE ISSUER OF THIS NOTE OF AN OPINION OF COUNSEL REASONABLY ACCEPTABLE TO THE
ISSUER THAT REGISTRATION IS NOT REQUIRED FOR SUCH TRANSFER, OR (3) THE
SUBMISSION TO THE ISSUER OF THIS NOTE OF OTHER EVIDENCE, REASONABLY ACCEPTABLE
TO THE ISSUER, TO THE EFFECT THAT ANY SUCH SALE, PLEDGE, HYPOTHECATION OR
TRANSFER WILL NOT BE IN VIOLATION OF THE UNITED STATES SECURITIES ACT OF 1933,
AS AMENDED, OR OTHER APPLICABLE SECURITIES LAWS OF ANY STATE, OR ANY RULES OR
REGULATIONS PROMULGATED THEREUNDER.

THE PAYMENT OF THE PRINCIPAL OF, AND INTEREST ON, AND ALL OTHER AMOUNTS OWING IN
RESPECT OF THE INDEBTEDNESS EVIDENCED BY, THIS NOTE, IS AND SHALL BE EXPRESSLY
SUBORDINATED, TO THE EXTENT AND IN THE MANNER SET FORTH HEREIN AND IN THAT
CERTAIN SUBORDINATION AND INTERCREDITOR AGREEMENT DATED AS OF JULY 19, 2002, OR
ANY OTHER SUBORDINATION AGREEMENT NOW OR HEREAFTER EXECUTED, BY THE ISSUER OF
THE NOTE AND THE HOLDER IN FAVOR OF BANK OF AMERICA, N.A., A NATIONAL BANKING
ASSOCIATION, ITS SUCCESSORS OR ASSIGNS, AS AGENT FOR THE HOLDERS OF SENIOR DEBT
AND THE OTHER PARTIES SIGNATORY THERETO (THE "SUBORDINATION AGREEMENT"). A COPY
OF THE SUBORDINATION AGREEMENT IS ON FILE AT THE MAIN HOUSTON OFFICE OF THE
ISSUER AND IS AVAILABLE FOR INSPECTION AT SUCH OFFICE.

[HELLER AND MIDWEST ONLY - THE SECURITIES REPRESENTED BY THIS CERTIFICATE ARE
SUBJECT TO CERTAIN RESTRICTIONS ON TRANSFER AND CERTAIN VOTING AGREEMENTS ALL AS
SET FORTH IN A CERTAIN INVESTORS AGREEMENT OF CASTLE DENTAL CENTERS, INC., DATED
AS OF JULY 19, 2002, A COPY OF WHICH WILL BE MAILED TO THE HOLDER WITHOUT CHARGE
WITHIN FIVE DAYS OF A WRITTEN REQUEST THEREFOR.]

THE SECURITIES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN
RESTRICTIONS SET FORTH IN A STOCKHOLDERS AGREEMENT, DATED AS OF JULY 19, 2002. A
COPY OF SUCH AGREEMENT MAY BE OBTAINED BY THE HOLDER HEREOF AT THE COMPANY'S
PRINCIPAL PLACE OF BUSINESS WITHOUT CHARGE.

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$_______________________                                          July, 19, 2002
                                                               Chicago, Illinois

FOR VALUE RECEIVED, CASTLE DENTAL CENTERS, INC., a Delaware corporation (the
"Company"), hereby promises to pay to the order of __________________________,
a[n] ___________________ or [its/his] registered assigns ("Holder") the
principal amount of__________________________________ AND __/00 DOLLARS
($______________), on July __, 2007 (the "Maturity Date"). The Company further
promises to pay interest on the outstanding unpaid principal amount hereof, as
provided in the Purchase Agreement (as defined below), from the date hereof
until payment in full hereof at the applicable rate specified in subsection
3.02(a) of the Purchase Agreement; provided, however, that if Holder so elects,
following the occurrence and during the continuance of an Event of Default, the
Company promises to pay to Holder interest on the unpaid principal amount hereof
at the applicable rate specified in subsection 3.02(b) of the Purchase
Agreement. Interest shall be payable in accordance with the provisions specified
in subsection 3.02(c) of the Purchase Agreement.

     This Convertible Subordinated Note (hereinafter referred to as the "Note")
is one of the notes (collectively, together with all notes issued in connection
with the Purchase Agreement (as defined below), the "Notes") being issued by the
Company pursuant to the terms of the Senior Subordinated Note and Warrant
Purchase Agreement, dated as of July 19, 2002 (the "Purchase Agreement"),
executed by and among the Company, the Holder and the other parties thereto. All
terms which are capitalized and used herein (which are not otherwise
specifically defined herein) and which are defined in the Purchase Agreement
shall have the meanings set forth in the Purchase Agreement.

     1.      Payments of Principal and Interest. The principal amount hereof and
all accrued and unpaid interest hereon, to the extent that it has not been
converted into shares of Common Stock pursuant to Section 2 hereof, shall be
payable in full on the Maturity Date. All payments of principal and interest on
this Note shall be made in lawful money of the United States of America by wire
transfer of immediately available funds to such account as the Holder may from
time to time designate by written notice in accordance with the provisions of
this Note. If a payment hereunder becomes due and payable on a day that is not a
Business Day, the payment may be made on the next succeeding Business Day, and
such extension of time shall be included in the computation of the amount of
interest due on such succeeding Business Day. Checks, drafts or similar items of
payment received by Holder shall not constitute payment, but credit therefor
shall, solely for the purpose of computing interest earned by Holder, be given
in accordance with the Purchase Agreement. In no contingency or event whatsoever
shall interest charged hereunder, however such interest may be characterized or
computed, exceed the highest rate permissible under any law which a court of
competent jurisdiction determines is applicable hereto. In the event that such a
court determines that Holder has received interest hereunder in excess of the
highest rate applicable hereto, such excess shall be applied in accordance with
the terms of the Purchase Agreement.

     2.      Conversion of Notes. This Note shall be convertible into shares of
the

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Company's common stock, $.001 par value per share (the "Common Stock"), on the
terms and conditions set forth in this Section 2.

     (a)     Holder's Conversion Right; Mandatory Conversion. Subject to the
provisions of Section 2(c), at any time or times on or after the Issuance Date,
the Holder may convert, all or any part of the outstanding and unpaid principal
of and interest on this Note (the amount being converted, the "Conversion
Amount") into fully paid and nonassessable shares of Common Stock in accordance
with Section 2(d), at the Conversion Rate (as defined below).

     (b)     Conversion Rate. The number of shares of Common Stock issuable upon
any conversion of all or any part of this Note pursuant to Section 2(a) shall be
determined according to the following formula (the "Conversion Rate"):

                                Conversion Amount
                                Conversion Price

     (c)     Regulatory Problem. In the event the Holder determines that it has
a Regulatory Problem (as defined below), the Holder shall have the right to
transfer this Note without regard to any restriction on transfer set forth in
this Note or the Purchase Agreement (other than applicable securities laws
restrictions) and the Company agrees to take all such actions as are reasonably
requested by the Holder in order to (i) effectuate and facilitate any transfer
by the Holder of this Note to any Person designated by Holder (subject to
compliance with applicable federal and state securities laws) or (ii) to permit
the Holder (or any Affiliate thereof) to exchange all or any portion of the
Common Stock then held by, or issuable to, it on a "share-for-share" basis for
shares of a class of non-voting stock of the Company, which non-voting stock
shall be identical in all respects to such Common Stock, except such stock shall
be non-voting and shall be convertible into Common Stock on such terms as are
requested by such Holder in light of regulatory considerations then prevailing.
The Company agrees to enter into such additional agreements, adopt such
amendments hereto and to the Certificate of Incorporation of the Company and to
take such additional actions as are reasonably requested by the Holder in order
to effectuate the intent of the foregoing. For purposes hereof, a "Regulatory
Problem" means any set of facts or circumstances wherein the Holder reasonably
believes it is not entitled to hold, or exercise any significant right with
respect to, the Common Stock. For purposes of this Note, the term Common Stock
shall be deem to include any non-voting common stock to be issued pursuant to
this Section 2(c).

     (d)     Mechanics of Conversion. Any conversion of all or any portion of
this Note shall be conducted in the following manner:

     (i)     Holder's Delivery Requirements. To convert this Note into shares of
Common Stock on any date set forth in the Conversion Notice (as hereinafter
defined) by the Holder (the "Conversion Date"), the Holder hereof shall (A)
deliver, by facsimile (or otherwise deliver), for receipt on or prior to 11:59
p.m. New York time on such date, a fully executed notice of conversion in the
form attached hereto as Exhibit A (the "Conversion Notice") to the Company with
a copy thereof to the Company's designated transfer agent (the "Transfer Agent")
and (B) if all of the shares of Common Stock then represented by this Note are
being converted, surrender to a common carrier for delivery to the Company as
soon as practicable following such

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date the original Note (or an indemnification undertaking with respect to such
Note in the case of its loss, theft or destruction).

     (ii)    Company's Response. Upon receipt by the Company of a Conversion
Notice, the Company shall (A) promptly, and in no event later than two (2)
Business Days after receipt, send, via facsimile, a confirmation of receipt of
such Conversion Notice to such Holder and the Transfer Agent, which confirmation
shall constitute an instruction to the Transfer Agent to process such Conversion
Notice in accordance with the terms herein, and (B) on or before the third
Business Day following the date of receipt by the Company of such Conversion
Notice (the "Share Delivery Date"): (i) issue and deliver to the address as
specified in the Conversion Notice, a certificate, registered in the name of the
Holder, for the number of shares of Common Stock to which the Holder is
entitled, or (ii) provided the Transfer Agent is participating in The Depository
Trust Company ("DTC") Fast Automated Securities Transfer Program and provided
that the Holder is eligible to receive shares through DTC, upon the request of
the Holder, credit the aggregate number of shares of Common Stock to which the
Holder is entitled upon such conversion to the Holder's balance account with DTC
through its Deposit Withdrawal Agent Commission system. If the Note is delivered
to the Company by the Holder and less than the entire outstanding principal of
and accrued interest on, this Note is submitted for conversion, the Company
shall, as soon as practicable and in no event later than three (3) Business Days
after receipt of the Note (the "Note Delivery Date") and at its own expense,
issue and deliver to the Holder a new Note for the amount not converted.

     (iii)   Dispute Resolution. In the case of a dispute as to the
determination of the arithmetic calculation of the Conversion Rate, the Company
shall instruct the Transfer Agent to issue to the Holder the number of shares of
Common Stock that is not disputed and shall transmit an explanation of the
disputed arithmetic calculations to the Holder via facsimile within two (2)
Business Days of receipt of such Holder's Conversion Notice or other date of
determination. If such Holder and the Company are unable to agree upon the
determination of the arithmetic calculation of the Conversion Rate within one
(1) Business Day of such disputed arithmetic calculation being transmitted to
the Holder, then the Company shall within one (1) Business Day submit via
facsimile the disputed arithmetic calculation of the Conversion Rate to the
Company's independent, outside accountant. Furthermore, in the event the holders
of Notes holding a majority of the then outstanding principal amount of all the
Notes, on the one hand, and the Company, on the other hand, are unable to agree
on the Fair Market Value in accordance with the definition of Closing Bid Price,
then the Company shall submit as soon as reasonably practicable after it becomes
apparent that such holders and the Company do not agree as to the Fair Market
Value, the disputed determination of the Fair Market Value to an independent,
reputable investment bank selected by the Company and approved by the holders
holding a majority of the then outstanding principal amount of all the Notes.
The Company shall cause the investment bank or the accountant, as the case may
be, to perform the determinations or calculations and notify the Company and all
the holders of the Notes of the results no later than forty-eight (48) hours
from the time it receives the disputed determinations or calculations. Such
investment bank's or accountant's determination or calculation, as the case may
be, shall be binding upon the Company and all the holders of the Notes. Within
one (1) Business Day of the accountant's determination of the calculation of the
Conversion Rate, the Company shall deliver to the Holder the balance of Common
Stock that such Holder is entitled to as provided herein (such date also deemed
to be a Share Delivery Date) and any failure to do so will subject the

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Company to the provisions of subsection (v) below.

     (iv)    Record Holder. The Person or Persons entitled to receive the shares
of Common Stock issuable upon a conversion of this Note shall be treated for all
purposes as the record holder or holders of such shares of Common Stock on the
Conversion Date.

     (v)     Company's Failure to Timely Convert.

     (A)     Cash Damages. If within three (3) Business Days after the Company's
receipt of the Conversion Notice (i) the Company shall fail to issue and deliver
a certificate to the Holder or, at the Holder's election, credit the Holder's
balance account with DTC for the number of shares of Common Stock to which such
Holder is entitled upon such Holder's conversion of this Note or (ii) the
Company shall fail to issue a new Note representing the principal amount to
which such Holder is entitled, if any, pursuant to Section 2(d)(ii), in addition
to all other available remedies which such Holder may pursue hereunder and under
the Purchase Agreement (including, but not limited to, indemnification
thereunder), the Company shall pay additional damages to such Holder for each
date after the Share Delivery Date such conversion is not timely effected and/or
each date after the Note Delivery Date such new Note is not delivered in an
amount equal to 0.5% of the sum of (a) the product of (I) the number of shares
of Common Stock not issued to the Holder on or prior to the Share Delivery Date
and to which such Holder is entitled and (II) the Closing Bid Price of the
Common Stock on the Share Delivery Date, and (b) in the event the Company has
failed to deliver a new Note to the Holder on or prior to the Note Delivery
Date, the product of (y) the number of shares of Common Stock issuable (without
regard to any limitations on conversions herein or elsewhere, including, but not
limited to, any limitations as a result of the actual number of shares of Common
Stock authorized for issuance by the Company) upon conversion of the principal
amount represented by the new Note, as of the Note Delivery Date and (z) the
Closing Bid Price of the Common Stock on the Note Delivery Date. If the Company
fails to pay the additional damages set forth in this Section 2(d)(v) within
five (5) Business Days of the date incurred, then the Holder entitled to such
payments shall have the right at any time, so long as the Company continues to
fail to make such payments, to require the Company, upon written notice, to
immediately issue, in lieu of such cash damages, the number of shares of Common
Stock equal to the quotient of (X) the aggregate amount of the damages payments
described herein divided by (Y) the Conversion Price in effect on such
Conversion Date as specified by the Holder in the Conversion Notice.

     (B)     Void Conversion Notice. If for any reason the Holder has not
received all of the shares of Common Stock to which it is entitled to prior to
the tenth (10th) Business Day after the expiration of the Share Delivery Date
with respect to a conversion of this Note, then the Holder, upon written notice
to the Company, may void its Conversion Notice with respect to, and retain or
have returned or restored as of the Conversion Date, as the case may be, any
principal amount and accrued and unpaid interest on this Note that has not been
converted pursuant to such Holder's Conversion Notice; provided that the voiding
of a Holder's Conversion Notice shall not effect the Company's obligations to
make any payments which have accrued prior to the date of such notice pursuant
to Section 2(d)(v)(A) or otherwise.

     (vi)    Book-Entry. Notwithstanding anything to the contrary set forth
herein, upon conversion of any portion of this Note in accordance with the terms
hereof, the Holder thereof

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shall not be required to physically surrender this Note to the Company unless
the full Conversion Amount then outstanding is being converted. The Company
shall maintain records showing the Conversion Amount so converted and the dates
of such conversions or shall use such other method, reasonably satisfactory to
the Holder, so as to account for the dollars of principal and interest that are
represented by the Note where conversions have occurred without the physical
surrender of this Note. Notwithstanding the foregoing, if any portion of this
Note is converted as aforesaid, thereafter, the Holder may not transfer this
Note unless the Holder first physically surrenders this Note to the Company,
whereupon the Company will forthwith issue and deliver to the Holder a new Note
of like tenor, registered as the Holder may request, representing in the
aggregate the remaining principal amount represented by this Note. The Holder,
by acceptance of this Note or such new Note, acknowledges and agrees that, by
reason of the provisions of this paragraph, following conversion of any portion
of this Note, the principal amount represented by this Note may be less than the
principal amount set forth on the face hereof.

     (vii)   Fractional Shares. No fractional shares of Common Stock or scrip
shall be issued to any Holder in connection with the conversion of this Note.
Instead of any fractional shares of Common Stock that would otherwise be
issuable to such Holder, the Company will pay to such Holder a cash adjustment
in respect of such fractional interest in an amount equal to that fractional
interest of the Closing Bid Price on the Conversion Date.

     (viii)  Pro Rata Conversion. In the event the Company receives a Conversion
Notice from more than one holder of the Notes for the same Conversion Date and
the Company, after fully complying with Section 3(b) below, can convert some,
but not all, of such Notes, the Company shall convert from each holder of such
Notes electing to have Notes converted at such time a pro rata amount of such
holder's Note submitted for conversion based on the amount of the Note submitted
for conversion on such date by such holder relative to the aggregate amount of
all amounts of all the Notes submitted for conversion on such date.

     (e)     Taxes. The Company shall pay any and all taxes that may be payable
with respect to the issuance and delivery of Common Stock upon the conversion of
the Notes.

     (f)     Certain Adjustments. In addition to any other adjustments provided
herein, this Note and the number of shares of Common Stock to which this Note is
convertible into will be subject to adjustment from time to time as provided in
this Section 2(f).

     (i)     Adjustment of Conversion Price upon Subdivision or Combination of
Common Stock. If the Company at any time subdivides (by any stock split, stock
dividend, recapitalization or otherwise) one or more classes of its outstanding
shares of Common Stock into a greater number of shares, the Conversion Price in
effect immediately prior to such subdivision will be proportionately reduced. If
the Company at any time combines (by combination, reverse stock split or
otherwise) one or more classes of its outstanding shares of Common Stock into a
smaller number of shares, the Conversion Price in effect immediately prior to
such combination will be proportionately increased.

     (ii)    Other Events. If any event occurs of the type contemplated by the
provisions of this Section 2(f) but not expressly provided for by such
provisions, then the Company's Board of Directors will make an appropriate
adjustment in the Conversion Price so as to protect the rights

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of the Holder.

     (g)     Other Rights of Holder.

     (i)     Reorganization, Reclassification, Consolidation, Merger or Sale.
Any recapitalization, reorganization, reclassification, consolidation, merger,
sale of all or substantially all of the Company's assets to another Person,
conveyance to another Person of the property of the Company as an entirety or
substantially as an entirety or other transaction which is effected in such a
way that holders of Common Stock are entitled to receive (either directly or
upon subsequent liquidation) Capital Stock, securities or assets with respect to
or in exchange for Common Stock is referred to herein as an "Organic Change."
Prior to the consummation of, and as a condition to, any (i) sale or other
conveyance of all or substantially all of the Company's assets to an acquiring
Person or (ii) other Organic Change, the Company, or such other successor or
purchasing Person, as the case may be, shall make lawful and adequate provision
whereby the holder of this Note shall have the right thereafter to receive on
conversion of such Note the kind and amount of securities and property
receivable upon such Organic Change by a holder of the number of securities
issuable upon conversion of such Note immediately prior to such Organic Change.
The above provisions of this Section 2(g)(i) shall similarly apply to successive
Organic Changes.

     (ii)    Purchase Rights. If at any time the Company grants, issues or sells
any Options, Convertible Securities or rights to purchase stock, warrants,
securities or other property pro rata to the record holders of any class of
Common Stock (the "Purchase Rights"), then the Holder will be entitled to
acquire, upon the terms applicable to such Purchase Rights, the aggregate
Purchase Rights which such holder could have acquired if the Holder had held the
number of shares of Common Stock acquirable upon complete conversion of this
Note (without taking into account any limitations or restrictions on the
convertibility of the Note, including, but not limited to, any limitations as a
result of the actual number of shares of Common Stock authorized for issuance by
the Company) immediately before the date on which a record is taken for the
grant, issuance or sale of such Purchase Rights, or, if no such record is taken,
the date as of which the record holders of Common Stock are to be determined for
the grant, issue or sale of such Purchase Rights. For purposes of this Section
2(g)(ii), (i) "Convertible Securities" means any stock or securities (other than
Options) directly or indirectly convertible into or exchangeable or exercisable
for Common Stock, and (ii) "Options" means any rights, warrants or options to
subscribe for or purchase Common Stock or Convertible Securities.

     (iii)   Distribution of Securities. If securities of the Company or
securities of any subsidiary of the Company are distributed pro rata to holders
of any or all of the Company's securities, such number of securities will be
distributed to the holder of this Note or its assignee upon conversion of its
rights hereunder as such Note holder or assignee would have been entitled to if
this Note had been converted prior to such distribution, giving effect to all
adjustments called for by this Note. The provisions with respect to adjustment
of the Common Stock provided in this Note will also apply to the securities of
the Company and securities of any subsidiary to which the Note holder or its
assignee is entitled under this Section 2(g)(iii).

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     3.      Reservation of Shares. The Company covenants and agrees as follows:

     (a)     All shares of Common Stock that are issued upon the conversion of
this Note will, upon issuance, be validly issued, fully paid and nonassessable,
not subject to any preemptive rights, and free from all taxes, liens, security
interests, charges, and other encumbrances with respect to the issuance thereof,
other than taxes in respect of any transfer occurring contemporaneously with
such issue.

     (b)     The Company will at all times have authorized and reserved, and
keep available free from preemptive rights, a sufficient number of shares of
Common Stock to provide for the exercise of the rights represented by this Note
and if there is ever an insufficient amount of shares of Common Stock to provide
for the exercise of the rights represented by this Note (an "Authorized Share
Failure"), the Company shall immediately take all action necessary to cause the
number of the Company's authorized shares of Common Stock to be sufficient to
accomplish the Holder's right of conversion hereunder. Without limiting the
generality of the foregoing sentence, as soon as practicable after the date of
the occurrence of an Authorized Share Failure, but in no event later than 75
days after the occurrence of such Authorized Share Failure, the Company shall
hold a meeting of its stockholders for the authorization of either an increase
in the number of authorized shares of Common Stock or a reverse stock split with
respect to the Common Stock. In connection with such meeting, the Company shall
provide each stockholder with a proxy statement and shall use its best efforts
to solicit its stockholders' approval of such increase in authorized shares of
Common Stock or reverse stock split and to cause its board of directors to
recommend to the stockholders that they approve such proposal.

     (c)     The Company will not, by amendment of its Certificate of
Incorporation or through any reorganization, transfer of assets, consolidation,
merger, dissolution, issue or sale of securities, or any other voluntary action,
avoid or seek to avoid the observance or performance of any of the terms to be
observed or performed by it hereunder, but will at all times in good faith
assist in the carrying out of all the provisions of this Note and in the taking
of all such action as may reasonably be requested by the holder of this Note in
order to protect the exercise privilege of the holder of this Note against
dilution or other impairment, consistent with the tenor and purpose of this
Note.

     4.      Voting Rights. Prior to conversion of all or any portion of this
Note, the Holder shall have no voting rights, except as required by law,
including but not limited to the General Corporation Law of the State of
Delaware, and as expressly provided in this Note.

     5.      Note Holder Not Deemed a Stockholder; Notice of Corporate Action.
Except as otherwise specifically provided herein, the Holder shall not be
entitled to vote or receive dividends or be deemed the holder of shares of the
Company for any purpose, nor shall anything contained in this Note be construed
to confer upon the holder hereof, as such, any of the rights of a stockholder of
the Company or any right to vote, give or withhold consent to any corporate
action (whether any reorganization, issue of stock, reclassification of stock,
consolidation, merger, conveyance or otherwise), receive notice of meetings,
receive dividends or subscription rights, or otherwise, prior to the issuance to
the Holder of the Common Stock which he, she, or it is then entitled to receive
upon the due exercise of this Note. In addition, nothing contained in this Note
shall be construed as imposing any liabilities on such holder to purchase any
securities

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(upon conversion of this Note or otherwise) or as a stockholder of the Company,
whether such liabilities are asserted by the Company or by creditors of the
Company. Notwithstanding this Section 5, the Company will provide the Holder
with copies of the same notices and other information given to the stockholders
of the Company generally, contemporaneously with the giving thereof to the
stockholders. Furthermore, so long as this Note has not been converted or
redeemed in full:

     (A)     Immediately upon any adjustment of the Conversion Price, the
Company will give written notice thereof to the Holder of such adjustment and a
certificate of a firm of independent public accountants of recognized national
standing selected by the Board of Directors of the Company (who shall be
appointed at the Company's expense and who may be the independent public
accountants regularly employed by the Company) setting forth the number of
shares of Common Stock and the Conversion Price after such adjustment, setting
forth a brief statement of the facts requiring such adjustment and setting forth
the computation by which such adjustment was made.

     (B)     The Company will give written notice to the Holder at least twenty
(20) Business Days prior to the date on which the Company closes its books or
takes a record (i) with respect to any dividend or distribution upon the Common
Stock, (ii) with respect to any pro rata subscription offer to holders of Common
Stock or (iii) for determining rights to vote with respect to any Organic Change
(as defined in Section 2(g)(i)), dissolution or liquidation, provided that such
information shall have been made known to the public prior to or in conjunction
with such notice being provided to such holder.

     (C)     The Company will also give written notice to Holder at least twenty
(20) days prior to the date on which any Organic Change, dissolution or
liquidation will take place, provided that such information shall have been made
known to the public prior to or in conjunction with such notice being provided
to such holder.

     6.      (a) Transferability and Negotiability of Note. Title to this Note
may be transferred by endorsement (by the holder hereof executing the Assignment
Form attached hereto as Exhibit B) and delivery in the --------- same manner as
negotiable instruments transferable by endorsement and delivery.

     (b)     Exchange of Note Upon a Transfer. This Note shall be transferable
by the holder hereof to any of its Affiliates or any other Person subject only
to the restrictions set forth in the legend on the first page of this Note and
the restrictions set forth in the Stockholders Agreement [and the Investors
Agreement]. On surrender of this Note for exchange, properly endorsed on the
Assignment Form and subject to the provisions hereof with respect to compliance
with the Securities Act, the Company at its expense shall issue to or on the
order of such holder a new note of like tenor representing the remaining amount
(principal and interest) of this Note which has not been so transferred and
assigned.

     7.      Reissuance of Notes. Subject to Section 2(d)(vi), in the event of a
conversion or redemption pursuant to this Note of less than all of the
Conversion Amount represented by this Note, the Company shall promptly cause to
be issued and delivered to the Holder, upon tender by the Holder of the Note
converted or redeemed, a new note of like tenor representing the

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remaining amount (principal and interest) of this Note which has not been so
converted or redeemed.

     8.      Definitions. As used herein, unless the context otherwise requires,
the following terms have the following meanings:

     "Affiliate" of any Person shall mean (i) any Person directly or indirectly
controlled by, controlling or under common control with such first Person, (ii)
any director or officer of such first Person or of any Person referred to in
clause (i) above and (iii) if any Person in clause (i) above is an individual,
any member of the immediate family (including parents, spouse and children) of
such individual and any trust whose principal beneficiary is such individual or
one (1) or more members of such immediate family and any Person who is
controlled by any such member or trust. For purposes of this definition, any
Person which owns directly or indirectly ten percent (10%) or more of the
securities having ordinary voting power for the election of directors or other
governing body of a corporation or ten percent (10%) or more of the partnership
or other ownership interests of any other Person (other than as a limited
partner of such other Person) will be deemed to "control" (including, with its
correlative meanings, "controlled by" and "under common control with") such
corporation or other Person.

     "Business Day" means any day other than Saturday, Sunday or other day on
which commercial banks in the city of New York are authorized or required by law
to remain closed.

     "Capital Stock" or "capital stock" means (i) with respect to any Person
that is a corporation, any and all shares, interests, participations, rights in,
or other equivalents (however designated and whether voting and/or non-voting)
of corporate stock, and (ii) with respect to any other Person, any and all
partnership, limited partnership, limited liability company or other equity
interest of such Person, whether outstanding on the date of the Note or issued
after the date of the Note, and any and all rights or warrants exercisable or
exchangeable for or convertible into such capital stock.

     "Closing Bid Price" means, for any security as of any date, the last
closing bid price for such security on the Principal Market as reported by
Bloomberg Financial Markets ("Bloomberg"), or, if the Principal Market begins to
operate on an extended hours basis and does not designate the closing bid price,
then the last bid price of such security prior to 4:00 p.m. New York Time (or
such other time as the Principal Market publicly announces is the official close
of trading) as reported by Bloomberg, or, if the foregoing do not apply, the
last closing bid price of such security in the over-the-counter market on the
electronic bulletin board for such security as reported by Bloomberg, or, if no
closing bid price is reported for such security by Bloomberg, the last closing
trade price of such security as reported by Bloomberg, or, if no last closing
trade price is reported for such security by Bloomberg, the average of the bid
prices of any market makers for such security as reported in the "pink sheets"
by the National Quotation Bureau, Inc. If the Closing Bid Price cannot be
calculated for such security on such date on any of the foregoing bases, the
Closing Bid Price of such security on such date shall be the fair market value
(the "Fair Market Value") as mutually determined by the Company, on the one
hand, and the holders of a majority of the then outstanding principal amount of
the Notes. If the Company and such holders are unable to agree upon the Fair
Market Value, then such dispute shall be resolved pursuant to Section 2(d)(iii)
above. All such determinations to be appropriately

<PAGE>

adjusted for any stock dividend, stock split or other similar transaction during
such period.

     "Conversion Price" means initially [.53566616], as such price may be
subsequently adjusted as provided herein.

     ["Investors Agreement" means that certain Investors Agreement, dated as of
July 19, 2002, by and among the Company, Holder and certain other parties
thereto. Heller and Midwest only]

     "Issuance Date" means the date of original issuance date of the Note.

     "Person" means any individual, limited liability company, partnership,
joint venture, association, joint-stock company, corporation, trust,
unincorporated organization, estate and other entity or government or any
department or agency thereof.

     "Principal Market" means the principal securities exchange or trading
market for the Common Stock.

     "Securities Act" means the Securities Act of 1933, as amended.

     "Stockholders Agreement" means that certain Stockholders Agreement, dated
as of July 19, 2002, among the Company and each of the stockholders and warrant
holders a party thereto.

     9.      Lost or Stolen Notes. Promptly upon receipt by the Company of
evidence satisfactory to the Company of the loss, theft, destruction or
mutilation of any Note, and, in the case of loss, theft or destruction, of an
indemnification undertaking by the Holder to the Company in a form reasonably
acceptable to the Company and, in the case of mutilation, upon surrender and
cancellation of the Notes, the Company shall execute and deliver new notes of
like tenor and date; provided, however, the Company shall not be obligated to
re-issue notes if the Holder contemporaneously requests the Company to convert
such remaining principal amount into Common Stock.

     10.     Payment of Collection, Enforcement and Other Costs. If any suit or
action is instituted or attorneys are employed to collect or enforce this Note
or any part thereof, the Company hereby promises and agrees to pay all costs of
collection, including attorneys' fees and court costs.

     11.     Cancellation. After all principal and accrued interest at any time
owed on this Note has been paid in full, this Note shall automatically be deemed
canceled, shall be surrendered to the Company for cancellation and shall not be
reissued.

     12.     Waiver of Notice. To the extent permitted by law, the Company
hereby waives demand, notice, protest and all other demands and notices in
connection with the delivery, acceptance, performance, default or enforcement of
this Note and the Purchase Agreement.

     13.     Governing Law. The corporate laws of the State of Delaware shall
govern all issues concerning the relative rights of the Company and its
stockholders. All other questions concerning the construction, validity,
enforcement, interpretation and performance of this Note

<PAGE>

shall be governed by the laws of the State of Illinois, without giving effect to
provisions thereof regarding conflict of laws.

     14.     Remedies, Characterizations, Other Obligations, Breaches and
Injunctive Relief. The remedies provided in this Note shall be cumulative and in
addition to all other remedies available under this Note, at law or in equity
(including a decree of specific performance and/or other injunctive relief), no
remedy contained herein shall be deemed a waiver of compliance with the
provisions giving rise to such remedy and nothing herein shall limit a holder's
right to pursue actual damages for any failure by the Company to comply with the
terms of this Note. The Company covenants to each Holder of Notes that there
shall be no characterization concerning this instrument other than as expressly
provided herein. Amounts set forth or provided for herein with respect to
payments, conversion and the like (and the computation thereof) shall be the
amounts to be received by the Holder thereof and shall not, except as expressly
provided herein, be subject to any other obligation of the Company (or the
performance thereof). The Company acknowledges that a breach by it of its
obligations hereunder will cause irreparable harm to the holders of the Notes
and that the remedy at law for any such breach may be inadequate. The Company
therefore agrees that, in the event of any such breach or threatened breach, the
holders of the Notes shall be entitled, in addition to all other available
remedies, to an injunction restraining any breach, without the necessity of
showing economic loss and without any bond or other security being required.

     15.     Specific Shall Not Limit General; Construction. No specific
provision contained in this Note shall limit or modify any more general
provision contained herein. This Note shall be deemed to be jointly drafted by
the Company and all holders and shall not be construed against any person as the
drafter hereof.

     16.     Failure or Indulgence Not Waiver. No failure or delay on the part
of this Note in the exercise of any power, right or privilege hereunder shall
operate as a waiver thereof, nor shall any single or partial exercise of any
such power, right or privilege preclude other or further exercise thereof or of
any other right, power or privilege.

     17.     Amendments. Any provision of this Note may be amended, modified or
waived with the prior written consent of the Company and the holders of fifty
one percent (51%) of the then-outstanding principal balance of the Notes;
provided, however, no amendment, modification or waiver can be effected if, by
its terms, such amendment, modification or waiver adversely affects one (1)
Holder without having the same adverse effect on all other Holders without the
prior written consent of such adversely affected Holder.

     18.     Notices. Whenever notice is required to be given under this Note,
unless otherwise provided herein, such notice shall be given in accordance with
the notice provisions in the Purchase Agreement. Any party may by notice given
in accordance with this Section 18 designate another address or person for
receipt of notices hereunder.

     19.     Registration Rights. If the holder hereof is a party to, or an
assignee of rights under, that certain Registration Rights Agreement, dated as
of July 19, 2002, by and among the Company and the Persons who are signatories
thereto, such holder shall be entitled to include with such holder's registrable
securities any shares of Common Stock or other securities received

<PAGE>

upon conversion of this Note, all on the terms and conditions as set forth in
such Registration Rights Agreement.

                 - Remainder of Page Intentionally Left Blank -
                            [Signature Page Follows]

<PAGE>

     IN WITNESS WHEREOF, the Company has executed this Note as of the day and
year first written above.

                                      CASTLE DENTAL CENTERS, INC., a
                                      Delaware corporation

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

                                              Note - ___________________________

<PAGE>

                                    EXHIBIT A

                           CASTLE DENTAL CENTERS, INC.
                                CONVERSION NOTICE

Reference is made to the Note issued by Castle Dental Centers, Inc. (the
"Company"). In accordance with and pursuant to the Note, the undersigned hereby
elects to convert the Conversion Amount (as defined in the Note) of the Note,
indicated below into shares of Common Stock, par value $.001 per share (the
"Common Stock"), of the Company as of the date specified below.

Date of Conversion:

Aggregate Conversion Amount to be converted:

Note no(s). of Note to be converted:

Please confirm the following information:

Conversion Price:

Number of shares of Common Stock to be issued:

Please issue the Common Stock into which the Note is being converted and, if
applicable, any check drawn on an account of the Company in the following name
and to the following address:

Issue to:

Facsimile Number:

Authorization:
By:
Title:

Dated:

Account Number:
 (if electronic book-entry transfer):

Transaction Code Number
 (if electronic book-entry transfer):

                                              Note - ___________________________

<PAGE>

                                EXHIBIT B TO NOTE

                                 ASSIGNMENT FORM

          FOR VALUE RECEIVED the undersigned registered owner of this Note
hereby sells, assigns and transfers unto the assignee named below all of the
rights of the undersigned under this Note, with respect to the principal amount
set forth below:

Name and Address of Assignee                               Principal Amount

and does hereby irrevocably constitute and appoint _______________________
attorney-in-fact to register such transfer onto the books of Castle Dental
Centers, Inc. maintained for the purpose, with full power of substitution in the
premises.

Date:                                    Print
                                         Name:
                                                     -------------------------
                                         Signature:
                                                     -------------------------
                                         Witness:
                                                     -------------------------

                                              Note - ___________________________<PAGE>

                                                                    Exhibit 10.6

                    SUBORDINATION AND INTERCREDITOR AGREEMENT

     THIS SUBORDINATION AND INTERCREDITOR AGREEMENT (this "Agreement") is
entered into as of July 19, 2002, by and among HELLER FINANCIAL, INC., a
Delaware corporation ("Heller"), MIDWEST MEZZANINE FUND II, L.P., a Delaware
limited partnership ("Midwest"), JAMES M. USDAN, an individual ("Usdan"; Usdan,
Heller and Midwest, are sometimes referred to individually as a "Junior
Creditor" and collectively as the "Junior Creditors"), CASTLE DENTAL CENTERS,
INC., a Delaware corporation (the "Company"), CASTLE DENTAL CENTERS OF
CALIFORNIA, L.L.C., a Delaware limited liability company ("Castle West"), CASTLE
DENTAL CENTERS OF FLORIDA, INC., a Florida corporation ("Castle Florida"),
CASTLE DENTAL CENTERS OF TENNESSEE, INC., a Tennessee corporation ("Castle
Tennessee"), CASTLE DENTAL CENTERS OF TEXAS, INC., a Texas corporation and
successor by merger to Dental World, Inc., a Texas corporation, and Castle
Dental Centers of Austin, Inc., a Texas corporation ("Castle Texas"), DENTCOR,
INC., a Florida corporation ("Dentcor"), CDC OF CALIFORNIA, INC., a Delaware
corporation ("CDC"), CASTLE TEXAS HOLDINGS, INC., a Delaware corporation
("Holdings"), and ACADEMY FOR DENTAL ASSISTANTS, INC., a Florida corporation
("Academy"), in favor of BANK OF AMERICA, N.A., a national banking association
formerly known as NationsBank, N.A., as agent ("Agent") for all Lenders party to
the Credit Agreement described below.

                                 R E C I T A L S

     A. The Company, Agent and Lenders have entered into the Credit Agreement,
pursuant to which, among other things, Agent and the Lenders have agreed,
subject to the terms and conditions set forth in the Credit Agreement, to
restructure certain loans and other financial accommodations to the Company.

     B. The Company and the Junior Creditors have entered into the Note Purchase
Agreement, pursuant to which, among other things, each Junior Creditor is
extending credit to the Company as evidenced by the Junior Notes.

     C. As an inducement to and as one of the conditions precedent to the
agreement of Lenders to consent to the transactions contemplated by the Note
Purchase Agreement, Lenders have required the execution and delivery of this
Agreement by the Junior Creditors, the Company and the Subsidiaries.

     NOW, THEREFORE, in order to induce Agent and Lenders to consent to the
transactions contemplated by the Note Purchase Agreement, and for other good and
valuable consideration, the receipt and sufficiency of which hereby are
acknowledged, the parties hereto hereby agree as follows:

     1. Definitions. All capitalized terms used in this Agreement without
definition shall have the meanings ascribed to such terms in the Credit
Agreement. In addition, the following terms shall have the following meanings in
this Agreement:

<PAGE>

Credit Agreement shall mean that certain Second Amended and Restated Credit
Agreement of even date herewith by and among the Company, Agent and the
financial institutions party thereto as Lenders, as the same may hereafter be
amended, restated, supplemented or otherwise modified from time to time as
permitted hereunder.

Enforcement Action means any action to enforce or attempt to enforce any right
or remedy available to any of the Junior Creditors to collect the Junior Debt,
including any action or proceeding (a) to accelerate the maturity of, or demand
as immediately due and payable, all or any part of the Junior Debt, or (b) to
commence, continue or participate in any judicial, arbitral or other proceeding,
or any collection, foreclosure or enforcement action of any kind, against the
Company or any Subsidiary or any of the Company's or any Subsidiary's assets
seeking, directly or indirectly, to enforce any rights or remedies, or to
enforce any of the obligations incurred by the Company or any Subsidiary, under
or in connection with the Junior Debt.

Junior Debt shall mean all of the obligations of the Company to the Junior
Creditors evidenced by the Junior Notes and all other amounts now or hereafter
owed by the Company to any Junior Creditor under any of the Junior Debt
Documents.

Junior Debt Documents shall mean the Junior Notes, the Note Purchase Agreement
and any other loan document pertaining to Junior Debt; provided, however, the
term "Junior Debt Documents" shall not include any "Warrants" (as such term is
defined in the Note Purchase Agreement).

Junior Notes shall mean, collectively: (i) that certain Convertible Promissory
Note of even date herewith in the principal amount of $500,000.00 made by
Company to the order of Heller, (ii) that certain Convertible Promissory Note of
even date herewith in the principal amount of $500,000.00 made by Company to the
order of Midwest and (iii) that certain Convertible Promissory Note of even date
herewith in the principal amount of $700,000.00 made by Company to the order of
Usdan, in each instance as the same may be amended, substituted, supplemented or
otherwise modified from time to time as permitted hereunder.

Loan Documents shall have the meaning specified in the Credit Agreement.

Note Purchase Agreement shall mean that certain Senior Subordinated Note and
Warrant Purchase Agreement of even date herewith by and among the Company and
each of the Junior Creditors, as the same may hereafter be amended, restated,
supplemented or otherwise modified from time to time as permitted hereunder.

Proceeding shall mean any voluntary or involuntary insolvency, bankruptcy,
receivership, custodianship, liquidation, dissolution, reorganization,
assignment for the benefit of creditors, appointment of a custodian, receiver,
trustee or other officer with similar powers or any other proceeding for the
liquidation, dissolution or other winding up of a Person.

Reorganization Subordinated Securities shall mean (a) any equity securities
issued in

                                       2

<PAGE>

substitution of all or any portion of the Junior Debt that are subordinated in
right of payment to the Senior Debt (or any notes or other securities issued in
substitution of all or any portion of the Senior Debt), and (b) any notes or
other debt securities issued in substitution of all or any portion of the Junior
Debt that are subordinated to the Senior Debt (or any notes or other securities
issued in substitution of all or any portion of the Senior Debt) to the same
extent that the Junior Debt is subordinated to the Senior Debt pursuant to the
terms of this Agreement.

Senior Creditor shall mean the Agent and any party to the Credit Agreement as a
Lender.

Senior Debt shall mean: (a) all principal, interest, fees, reimbursements,
indemnifications and other amounts now or hereafter owed by the Company to
Senior Creditors under the Credit Agreement and other Loan Documents and (b) any
increases, extensions and rearrangements of the foregoing obligations under any
amendments, supplements and other modifications of the documents and agreements
creating the foregoing obligations to the extent permitted under Section 3
hereof; provided, however, that in no event shall the principal amount of the
Senior Debt exceed the sum of the aggregate principal amount of Senior Debt
outstanding on the date hereof plus $2,000,000, reduced by the amount of any
repayments and prepayments thereof (it being understood that no amounts expended
by any Senior Creditor to preserve the value of, or otherwise protect, the
Collateral, shall be subject to, or included within, the foregoing limitations).

Subsidiaries shall mean, collectively, Academy, Castle West, Castle Florida,
Castle Tennessee, Castle Texas, Dentcor, CDC, Holdings and any other Person now
or hereafter guaranteeing payment or performance of the Junior Debt. Each of the
Subsidiaries may be referred to individually as a Subsidiary.

2. Subordination.

     2.1 Subordination of Junior Debt to Senior Debt. The Company and each
Subsidiary covenants and agrees, and each Junior Creditor by its acceptance of a
Junior Note (whether upon original issue or upon transfer or assignment)
likewise covenants and agrees, that unless and until the Senior Debt shall have
been irrevocably paid in full, the payment and performance of the Junior Debt is
hereby made expressly subordinate and junior in right of payment and performance
to the prior payment and performance of all obligations and liabilities under
the Senior Debt to the extent and in the manner set forth in this Section 2.
Each holder of Senior Debt, whether now outstanding or hereafter created,
incurred, assumed or guaranteed, and whether such holder holds any Senior Debt
as of the date hereof or later becomes a holder by means of assignment or
otherwise, shall be deemed to have acquired Senior Debt in reliance upon the
provisions contained in this Agreement.

     2.2 Proceedings. In the event of any Proceeding involving the Company, (a)
all Senior Debt first shall be paid in full before any payment of or with
respect to the Junior Debt shall be made (other than a distribution of
Reorganization Subordinated Securities); and (b) any payment or distribution,
whether in cash, property or securities which, but for

                                       3

<PAGE>

the terms hereof, otherwise would be payable or deliverable in respect of the
Junior Debt (other than a distribution of Reorganization Subordinated
Securities), shall be paid or delivered directly to Agent (to be held and/or
applied by Agent in accordance with the terms of the Credit Agreement) until all
Senior Debt is irrevocably paid in full, and each Junior Creditor irrevocably
authorizes, empowers and directs all receivers, trustees, liquidators,
custodians, conservators and others having authority in the premises to effect
all such payments and distributions.

     In the event of any Proceeding involving any Subsidiary, (a) all payments
or distributions in such Proceeding shall be applied to Senior Debt before any
payment of or with respect to the Junior Debt shall be made (other than a
distribution of Reorganization Subordinated Securities); and (b) any payment or
distribution, whether in cash, property or securities which, but for the terms
hereof, otherwise would be payable or deliverable in respect of the Junior Debt
(other than a distribution of Reorganization Subordinated Securities) in such
Proceeding, shall be paid or delivered directly to Agent (to be held and/or
applied by Agent in accordance with the terms of the Credit Agreement) until all
Senior Debt is irrevocably paid in full, and each Junior Creditor irrevocably
authorizes, empowers and directs all receivers, trustees, liquidators,
custodians, conservators and others having authority in the premises to effect
all such payments and distributions.

     2.3 Limitation on Payments.

     (a) Neither the Company nor any Subsidiary may make, and no Junior Creditor
may receive, any payment or prepayment of any sum with respect to the Junior
Debt (other than reimbursement of actual and reasonable out-of-pocket costs and
expenses not to exceed, with respect to periods prior to the Closing Date,
$50,000) until all of the Senior Debt shall have been irrevocably paid in full.

     (b) The provisions of this subsection 2.3 shall not apply to any payment
with respect to which subsection 2.2 would be applicable.

     2.4 Subordination of Liens and Guarantees. The Junior Creditors will not
create, assume, or suffer to exist any lien, security interest, guaranty, or
assignment of collateral securing or guaranteeing the repayment of the Junior
Debt. Any judgment lien, and any other lien, security interest, guaranty or
assignment existing in violation of the foregoing shall be fully subordinate to
any lien, security interest, guaranty or assignment in favor of the Senior
Creditors which secures any of the Senior Debt, and the Junior Creditors, the
Company and the Subsidiaries shall immediately take any and all steps necessary
to effect the release of any such lien, security interest, assignment or
collateral or the termination of any such guaranty.

     2.5 Restriction on Action by the Junior Creditors.

     (a) Until the Senior Debt is paid in full, no Junior Creditor shall,
without the prior written consent of the Senior Lenders, take any Enforcement
Action with respect to the Junior Debt, except as permitted in the following
sentence. Upon the earlier to occur of:

                                       4

<PAGE>

          (i) acceleration of the Senior Debt; or

          (ii) commencement of a Proceeding with respect to the Company;

the Junior Creditors may accelerate the Junior Debt or take any other
Enforcement Action; provided, however, that if following the acceleration of the
Senior Debt, such acceleration is rescinded, then all Enforcement Actions taken
by the Junior Creditors shall likewise be rescinded if such Enforcement Action
is based solely on such acceleration.

     (b) Until the Senior Debt is irrevocably paid in full and notwithstanding
anything contained in the Junior Debt Documents, the Credit Agreement or any of
the other Loan Documents to the contrary, no Junior Creditor shall, without the
prior written consent of Agent (which consent may be withheld in the Agent's
sole discretion), agree to any amendment, modification or supplement to the
Junior Debt Documents, or make any increases, extensions, rearrangements,
amendments, supplements, or other modifications to the Junior Debt, the effect
of which is to (i) increase the maximum principal amount of the Junior Debt or
rate of interest on any of the Junior Debt, (ii) accelerate or shorten the dates
upon which payments of principal or interest on the Junior Debt are due, (iii)
change in a manner adverse to Company or any Subsidiary, or add, any event of
default or any covenant with respect to the Junior Debt, (iv) change any put,
redemption or prepayment provisions of the Junior Debt, or (v) alter the
subordination provisions with respect to the Junior Debt, including, without
limitation, subordinating the Junior Debt to any other debt.

     (c) Notwithstanding anything herein to the contrary, (i) the Junior
Creditors may file proofs of claim against the Company in any Proceeding
involving the Company, (ii) the Junior Creditors may at any time and from time
to time convert all or any portion of the Junior Notes into common stock of the
Company in accordance with the terms thereof and (iii) the Junior Creditors may
accrue interest at the default rate specified in the Note Purchase Agreement, or
otherwise give notices or file suits, actions or proceedings, and the Company
may agree to tolling agreements, to prevent the running of the relevant statute
of limitations, but no Junior Creditor may receive any property or payment on
account of any such suit, action or proceeding until the Senior Debt has been
irrevocably paid in full.

         2.6 Incorrect Payments. If any payment or distribution on account of
the Junior Debt not permitted to be made by the Company or any Subsidiary or
received by a Junior Creditor under this Agreement is received by such Junior
Creditor before all outstanding Senior Debt has been irrevocably paid in full,
such payment or distribution shall not be commingled with any asset of such
Junior Creditor, shall be held in trust by such Junior Creditor for the benefit
of Lenders and shall be immediately paid over to Agent, or its designated
representative, in the form received (together with any necessary endorsements)
for application (in accordance with the Credit Agreement) to the Senior Debt
until all outstanding Senior Debt has been irrevocably paid in full.

     2.7 Sale, Transfer, etc. No Junior Creditor shall sell, assign or otherwise
transfer all

                                       5

<PAGE>

or any portion of the Junior Debt or any Junior Debt Document unless prior to
the consummation of any such action, the transferee thereof shall execute and
deliver to Agent an agreement substantially identical to this Agreement,
providing for the continued subordination and forbearance of the Junior Debt to
the Senior Debt as provided herein and for the continued effectiveness of all of
the rights of the Senior Creditors arising under this Agreement. Any failure to
execute or deliver any such agreement shall make any attempted sale, assignment
or other transfer of any portion of the Junior Debt or any Junior Debt Document
void ab initio. The subordination effected hereby shall survive any sale,
assignment, pledge, disposition or other transfer of all or any portion of the
Junior Debt, and the terms of this Agreement shall be binding upon the
successors and assigns of such Junior Creditor, as provided in Section 10 below.

     2.8 Legends. The Junior Creditors shall cause all Junior Debt to be
evidenced by a note, debenture, instrument, or other writing evidencing the
Junior Debt and will inscribe a statement or legend thereon to the effect that
such note, debenture, instrument, or other writing is subordinated to the Senior
Debt in favor of the Senior Creditors in the manner and to the extent set forth
in this Agreement.

     3. Modifications to Senior Debt. This is an irrevocable agreement of
subordination and the Senior Creditors may, without notice to any of the parties
hereto and without impairing or releasing the obligations of the Company, any
Subsidiary and the Junior Creditors hereunder, (a) create Senior Debt by
extending credit under the Credit Agreement; (b) change the terms of or increase
the amount of the Senior Debt by increasing, extending, rearranging, amending,
supplementing, or otherwise modifying any of the Loan Documents or other
instruments or agreements creating Senior Debt; (c) sell, exchange, release, or
otherwise deal with any collateral securing any Senior Debt; (d) release anyone,
including the Company, any Subsidiary or any guarantor, liable in any manner for
the payment or collection of any Senior Debt; (e) exercise or refrain from
exercising any rights against the Company or any Subsidiary or any other Person;
and (f) apply any sums received by any of the Senior Creditors, from whatever
source, to the payment of the Senior Debt; provided, however, that neither Agent
nor any of the Lenders shall (a) increase the Senior Debt to an amount greater
than the sum of the aggregate principal amount of Senior Debt outstanding on the
date hereof plus $2,000,000, reduced by the amount of any repayments and
prepayments thereof (it being understood that no amounts expended by any Senior
Creditor to preserve the value of, or otherwise protect, the Collateral, shall
be subject to, or included within, the foregoing limitations), (b) increase the
interest rate with respect to the Senior Debt by more than three hundred (300)
basis points from any interest rate specified in the Credit Agreement as in
effect on the date hereof, or (c) extend the final maturity of the Senior Debt
to a date later than June 30, 2007.

     4. Continued Effectiveness of this Agreement. The terms of this Agreement,
the subordination effected hereby, and the rights and the obligations of the
Junior Creditors, the Company, the Subsidiaries, Agent and Lenders arising
hereunder shall not be affected, modified or impaired in any manner or to any
extent by: (a) any amendment or modification of or supplement to the Credit
Agreement, any of the other Loan Documents or any of the Junior Debt Documents,
in each instance, to the extent permitted herein; (b) the validity or
enforceability of any of such documents; or (c) any exercise or non-exercise of
any right, power or remedy under or in respect of the Senior Debt or the Junior
Debt or any of the instruments or documents referred to in clause (a) above. The
Junior Creditors and each other holder of Junior Debt hereby

                                       6

<PAGE>

acknowledge that the provisions of this Agreement are intended to be enforceable
at all times, whether before the commencement of, after the commencement of, in
connection with or premised on the occurrence of a Proceeding.

     5. Cumulative Rights, No Waivers. Each and every right, remedy and power
granted to Agent or Lenders hereunder shall be cumulative and in addition to any
other right, remedy or power specifically granted herein, in the Credit
Agreement or the other Loan Documents or now or hereafter existing in equity, at
law, by virtue of statute or otherwise, and may be exercised by Agent or
Lenders, from time to time, concurrently or independently and as often and in
such order as Agent or Lenders may deem expedient. Any failure or delay on the
part of Agent or Lenders in exercising any such right, remedy or power, or
abandonment or discontinuance of steps to enforce the same, shall not operate as
a waiver thereof or affect the rights of Agent or Lenders thereafter to exercise
the same, and any single or partial exercise of any such right, remedy or power
shall not preclude any other or further exercise thereof or the exercise of any
other right, remedy or power, and no such failure, delay, abandonment or single
or partial exercise of the rights of Agent or Lenders hereunder shall be deemed
to establish a custom or course of dealing or performance among the parties
hereto.

     6. Modification. Any amendment, modification or waiver of any provision of
this Agreement shall not be effective in any event unless the same is in writing
and signed by Agent, Company, the Subsidiaries and each Junior Creditor and then
such amendment, modification or waiver shall be effective only in the specific
instance and for the specific purpose given.

     7. Additional Documents and Actions. The Company, each Subsidiary and the
Junior Creditors at any time, and from time to time, after the execution and
delivery of this Agreement, will execute and deliver such further documents as
Agent reasonably may request that may be necessary in order to confirm the
subordination effected herein.

     8. Notices. Unless otherwise specifically provided herein, any notice or
other communication required or permitted to be given shall be in writing
addressed to the respective party as set forth below and may be personally
served, telecopied or sent by overnight courier service or certified or
registered United States mail and shall be deemed to have been given (a) if
delivered in person, when delivered; (b) if delivered by telecopy, on the date
of transmission if transmitted on a Business Day before 1:00 p.m. (Central time)
or, if not, on the next succeeding Business Day; (c) if delivered by overnight
courier, two (2) Business Days after delivery to such courier properly
addressed; or (d) if by United States mail, four (4) Business Days after deposit
in the United States mail, postage prepaid and properly addressed.

     Notices shall be addressed as follows:

         (a)      If to Agent:

                  Bank of America, N.A.
                  901 Main Street, 11th Floor
                  Dallas, Texas 75202-3714
                  Attention: Mark Henze
                  Telecopy: 214.209.3444

                                       7

<PAGE>

         (b)      If to Heller:

                  HELLER FINANCIAL, INC.
                  c/o Heller Healthcare Financial Services
                  500 West Monroe Street
                  Chicago, Illinois  60661
                  Attention: Michael Sznajder
                  Telecopy: 312.441.7598

                  With a copy to:

                  HELLER FINANCIAL, INC.
                  c/o Heller Healthcare Financial Services
                  2 Wisconsin Circle, 4th Floor
                  Chevy Chase, Maryland 20815
                  Attention:  Katherine R. Lofft, Esq.
                  Telecopy:  301.664.9866

         (c)      If to Midwest:

                  Midwest Mezzanine Fund II, L.P.
                  208 South LaSalle Street, 10th floor
                  Chicago, Illinois 60604-1003
                  Attention: J. Allan Kayler
                  Telecopy: 312.553.6647

                  and

                  Foley & Lardner
                  Three First National Plaza, Suite 4100
                  Chicago, Illinois 60602
                  Attention: Van E. Holkeboer, Esq.
                  Telecopy:  312.558.3310

         (d)      If to Usdan:

                  James M. Usdan
                  c/o Castle Dental Centers, Inc.
                  3701 Kirby Drive, Suite 550
                  Houston, Texas  77098
                  Attention: James Usdan
                  Telecopy: 713.490.8420

                  and

                                       8

<PAGE>

                  Porter & Hedges, LLP
                  700 Louisiana, 35th floor
                  Houston, Texas 77002
                  Attention: Robert G. Reedy, Esq.
                  Telecopy: 713.226.0274

         (e)      If to  the Company or any Subsidiary:

                  c/o Castle Dental Centers, Inc.
                  3701 Kirby Drive, Suite 550
                  Houston, Texas  77098
                  Attention: James Usdan
                  Telecopy: 713.490.8420

or in any case, to such other address as the party addressed shall have
previously designated by written notice to the serving party, given in
accordance with this Section 8. A notice not given as provided above shall, if
it is in writing, be deemed given if and when actually received by the party to
whom given.

         9. Severability. In the event that any provision of this Agreement is
deemed to be invalid, illegal or unenforceable by reason of the operation of any
law or by reason of the interpretation placed thereon by any court or
governmental authority, the validity, legality and enforceability of the
remaining provisions of this Agreement shall not in any way be affected or
impaired thereby, and the affected provision shall be modified to the minimum
extent permitted by law so as most fully to achieve the intention of this
Agreement.

     10. Successors and Assigns. This Agreement shall inure to the benefit of
and shall be binding upon the parties hereto and their successors and assigns.

     11. Counterparts. This Agreement may be executed in one (1) or more
counterparts, each of which shall be deemed to be an original, but all of which
taken together shall be one and the same instrument.

     12. Defines Rights of Creditors. The provisions of this Agreement are
solely for the purpose of defining the relative rights of the Junior Creditors,
Agent and Lenders and shall not be deemed to create any rights or priorities in
favor of any other Person, including, without limitation, the Company or the
Subsidiaries.

     13. Subrogation. Subject to the irrevocable payment in full of all Senior
Debt, in the event and to the extent cash, property or securities otherwise
payable or deliverable to the holders of the Junior Debt shall have been applied
pursuant to this Agreement to the payment of Senior Debt, then and in each such
event, the holders of the Junior Debt shall be subrogated to the rights of each
holder of Senior Debt to receive any further payment or distribution in respect
of or applicable to the Senior Debt; and, for the purposes of such subrogation,
no payment or distribution to the holders of Senior Debt of any cash, property
or securities to which any holder of Junior Debt would be entitled except for
the provisions of this Agreement shall, and no payment over pursuant to the
provisions of this Agreement to the holders of Senior Debt by the holders of the
Junior Debt shall, as between Company and the Subsidiaries, their creditors
other

                                       9

<PAGE>

than the holders of the Senior Debt and the holders of Junior Debt, be deemed to
be a payment by the Company or the Subsidiaries to or on account of Senior Debt.

     14. Headings. The paragraph headings used in this Agreement are for
convenience only and shall not affect the interpretation of any of the
provisions hereof.

     15. Termination. Except for Sections 17, 18 and 19 hereof, this Agreement
shall terminate upon the irrevocable payment in full of all of the Senior Debt.

     16. Applicable Law. This Agreement shall be governed by and shall be
construed and enforced in accordance with the internal laws of the State of
Texas, without regard to conflicts of law principles.

     17. WAIVER OF JURY TRIAL. THE JUNIOR CREDITORS, THE COMPANY, THE
SUBSIDARIES AND AGENT EACH HEREBY WAIVE THEIR RESPECTIVE RIGHTS TO A JURY TRIAL
OF ANY CLAIM OR CAUSE OF ACTION BASED UPON OR ARISING OUT OF THIS AGREEMENT OR
ANY OF THE JUNIOR DEBT DOCUMENTS. THE JUNIOR CREDITORS, THE COMPANY, THE
SUBSIDIARIES AND AGENT ACKNOWLEDGE THIS WAIVER IS A MATERIAL INDUCEMENT TO ENTER
INTO A BUSINESS RELATIONSHIP, THAT EACH HAS RELIED ON THE WAIVER IN ENTERING
INTO THIS AGREEMENT AND THE LOAN DOCUMENTS AND THAT EACH WILL CONTINUE TO RELY
ON THE WAIVER IN THEIR RELATED FUTURE DEALINGS. EACH OF THE JUNIOR CREDITORS,
THE COMPANY, THE SUBSIDIARIES AND AGENT WARRANTS AND REPRESENTS THAT EACH HAS
HAD THE OPPORTUNITY OF REVIEWING THIS JURY WAIVER WITH LEGAL COUNSEL, AND THAT
EACH KNOWINGLY AND VOLUNTARILY WAIVES ITS JURY TRIAL RIGHTS.

     18. Enforcement. The Senior Creditors are hereby authorized to setoff and
apply any obligations owed by the Senior Creditors to the Company or a
Subsidiary against any obligations of the Company or a Subsidiary under this
Agreement. The provisions of this paragraph shall survive termination of this
Agreement.

     19. Reinstatement. The obligations of Junior Creditors under this Agreement
shall continue to be effective, or be reinstated after irrevocable payment in
full of the Senior Debt, as the case may be, if at any time any payment (an
"Invalidated Senior Payment") in respect of the Senior Debt is rescinded or
otherwise restored or returned by a Senior Creditor to the Company or any
Subsidiary by reason of any Proceedings, all as though such Invalidated Senior
Payment had not been made. To the extent the Junior Creditors have received any
payments with respect to the Junior Debt on or subsequent to the date of the
receipt by the Senior Creditors of such Invalidated Senior Payment and such
payments received by the Junior Creditors have not been rescinded or otherwise
restored or returned by the Senior Creditors to the Company or any Subsidiary or
paid over to the Senior Creditors, the Junior Creditors hereby agree to pay over
to the Senior Creditors the amount of such payments so received by the Junior
Creditors on or subsequent to such date to the extent necessary to restore to
the Senior Creditors the amount of the Invalidated Senior Payment.

                                       10

<PAGE>

     20. Termination of Prior Subordination Agreement. The parties hereto
acknowledge and agree that, upon the execution, delivery and effectiveness of
this Agreement, that certain Subordination and Intercreditor Agreement dated as
of January 31, 2000 by and among the Company, Agent, Heller, Midwest and the
Persons party thereto as "Guarantors" is terminated and shall be of no further
force or effect.

THIS WRITTEN AGREEMENT AND THE RELATED LOAN DOCUMENTS REPRESENT THE FINAL
AGREEMENT AMONG THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR,
CONTEMPORANEOUS, OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES.

THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES.

                 - Remainder of Page Intentionally Left Blank -
                            [Signature Page Follows]

                                       11

<PAGE>

         IN WITNESS WHEREOF, each Junior Creditor, the Company and the
Subsidiaries have caused this Agreement to be executed in favor of the Agent for
all the Lenders as of the date first above written.

COMPANY:                                                    AGENT:
-------                                                     -----

CASTLE DENTAL CENTERS, INC.,              BANK OF AMERICA, N.A.,
a Delaware corporation                    a national banking association

             /s/ John M. Slack                        /s/ Mark Henze
By:      _____________________________    By:      _____________________________
             John M. Slack                            Mark Henze
Name:    _____________________________    Name:    _____________________________
             Senior Vice President                    Senior Vice President
Title:   _____________________________    Title:   _____________________________

                                  SUBSIDIARIES:

JUNIOR CREDITORS:
                                          Academy for Dental Assistants, Inc., a
MIDWEST MEZZANINE FUND II, L.P.,          Florida corporation;
a Delaware limited partnership            Castle Dental Centers Of California,
                                          L.L.C., a Delawarelimited liability
                                          company;
By:    ABN AMRO Mezzanine Management      Castle Texas Holdings, Inc., a
       Management II, L.P., its general   Delaware corporation;
       partner                            Castle Dental Centers Of Texas, Inc.,
                                          a Texas corporation and successor by
                                          merger to Dental World, Inc., a Texas
                                          corporation, and Castle Dental centers
By:    ABN AMRO Mezzanine Management II,  of Austin, Inc., a Texas corporation;
       Inc., its general partner          CDC Of California, Inc., a Delaware

        /s/ Paul Kreie                    corporation;
By:    _______________________________    Castle Dental Centers Of Florida,
Name:  Paul Kreie                         Inc., a Florida corporation;
Title: Vice President                     Castle Dental Centers Of Tennessee,
                                          Inc., a Tennessee corporation; and
                                          Dentcor, Inc., a Florida corporation

HELLER FINANCIAL, INC., a Delaware                   /s/ John M. Slack
corporation                               By:      _____________________________
                                                     John M. Slack
                                          Name:    _____________________________
                                                     Senior Vice President
                                          Title:   _____________________________
           /s/ Michael Sznajder
By:      _____________________________
             Michael Sznajder
Name:    _____________________________
             Senior Vice President
Title:   _____________________________

JAMES M. USDAN, an individual

           /s/ James M. Usdan
By:      _____________________________
Name:    James M. Usdan

                                       12

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