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                                                                   Exhibit 10.13

                           NATIONAL DENTEX CORPORATION

                     SUPPLEMENTAL EXECUTIVE RETIREMENT PLAN

This Plan is effective as of the 4th day of April 1995, and is established by
National Dentex Corporation, organized and existing under the laws of the
Commonwealth of Massachusetts (hereinafter referred to as the "Company"), and is
binding upon the Company and those persons who are eligible to become
participants hereunder and have elected to do so by executing a Participation
Agreement (hereinafter referred to as "Participant" and collectively as the
"Participants").

     WITNESSETH THAT:

     WHEREAS, the Participants are employed by the Company; and

     WHEREAS, the Participants have performed their duties in a capable and
efficient manner, resulting in growth and progress of the Company; and

     WHEREAS, the experience of each Participant is such that assurance of his
continued service is desirous to further growth of the Company; and

     WHEREAS, the parties hereto desire to arrange compensation in a different
manner to more effectively provide for each Participant's retirement or death.

     NOW, THEREFORE, in consideration of the foregoing, the mutual covenants and
agreements hereinafter contained, and other good and valuable consideration,
receipt of which is hereby acknowledged, the Company hereby establishes the
National Dentex Corporation Supplemental Employee Retirement Plan as follows:

                                    ARTICLE I
                                   DEFINITIONS

1.1 "BENEFICIARY" shall mean any person, corporation, trust or other combination
of these, last designated in writing by a Participant to receive benefits
provided under this Plan. Such designation shall be filed with the Company and
shall be revocable at any time through written instruments similarly filed
without consent of any "Beneficiary". In the absence of any designation, the
benefits payable hereunder shall be delivered by the Company to the Executor(s)
or Administrator(s) of the Participant's estate.

1.2 "BOARD OF DIRECTORS" shall mean the Board of Directors of the Company.

1.3 "CLERK" shall mean the Clerk of the Company.

1.4 "COMMITTEE" shall mean the Executive Compensation Committee of the Board of
Directors.

1.5 "COMPANY" shall mean National Dentex Corporation.

1.6 "PARTICIPANT" shall mean any person designated by the Committee who elects
to participate in the Plan through execution of the Participation Agreement.


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1.7 "PARTICIPATION AGREEMENT" shall mean the form of written agreement, attached
hereto as Schedule A, which is entered into by and between the Company and a
Participant as a condition to participation in the Plan.

1.8 "RETIREMENT", "RETIRE", AND "RETIREMENT DATE" shall mean the date on which a
Participant attains the age sixty-five (65) or such later date as may be
acceptable to the Company.

1.9 "SERVICE" shall mean work performed by the Participant for the Company.

1.10 "CONSTRUCTION" The masculine gender when used herein shall be deemed to
include the feminine gender, and the singular may include the plural unless the
context clearly indicates to the contrary.

1.11 "AFTER TAX COST" shall mean the actual costs less an amount equal to the
combined federal and state income tax savings relating to the deduction of said
costs for federal and state tax purposes in the years such costs are incurred.

1.12 "POLICY" shall mean any policy of insurance purchased by the Company to
provide benefits with respect to a Participant under the Plan.

1.13 "PRE-RETIREMENT" shall mean the voluntary or involuntary termination of
service by a Participant prior to his Retirement Date.

1.14 "AGREEMENT" OR "PLAN" shall mean and include this Supplemental Executive
Retirement Plan and attached Schedules A and B.

1.15 "CASH VALUE" shall mean the cash surrender value of the Policy acquired by
the Company on a Participant's life, after reduction of all Policy loans used to
pay premiums and the After Tax Cost of interest, as provided herein.

1.16 "GROSSED-UP CASH VALUE" means the Cash Value of the policy acquired by the
Company on a Participant's life divided by an amount equal to one minus the
Company's marginal tax rate.

1.17 "TERMINATION BENEFIT" shall mean the benefit a Participant receives, as
provided in Article III, Section 2.

                                   ARTICLE II
                       RETIREMENT/PRE-RETIREMENT BENEFITS

(1) The Company agrees that each Participant may terminate his Service because
of Retirement upon the first day of the month following his 65th birthday, or
such later date as may be acceptable to the Company.

(2) Upon the date of a Participant's Retirement, such Participant shall elect
to:

          (i)  Retire and immediately receive benefits due; or

          (ii) Continue his employment and defer benefits which will accrue
               interest at the actual interest rate credited by the insurer.


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     Upon electing to receive benefits, the Participant shall receive 120 equal
monthly installments in an aggregate amount equal to the Grossed-Up Cash Value
of the Policy as of the date of Retirement, plus the projected Grossed-Up Cash
Value increase over the next nine consecutive Policy Years after the date of
Retirement, or at his election a lump sum amount equal to the Grossed-Up Cash
Value of the Policy as of the date of Retirement, payable within 30 days of the
Retirement Date.

(3) In the event a Participant shall cease rendering Service to the Company
prior to his date of Retirement, the Company shall stop paying annual premiums
on the Policy and the Retirement Benefit paid the Participant at Retirement Date
shall be 120 equal monthly installments, in an aggregate equal to the Grossed-Up
Cash Value of the Policy as of the date of Retirement, plus the projected
Grossed-Up Cash Value increase over the next nine consecutive Policy Years after
the date of Retirement, or at his election a lump sum amount equal to the
Grossed-Up Cash Value of the Policy as of the date of Retirement, payable within
30 days of Retirement Date.

(4) In the event a Participant should die prior to Retirement then:

          (a) Survivor Income Benefit Election. If the Participant elects the
survivor income benefit on the Participation Agreement and dies prior to
termination of his Service to the Company or his Retirement, the Company will
pay to the Participant's Beneficiary a sum equal to the Pre-Retirement amount
set forth on Schedule B, such amount to be payable in 120 monthly equal
installments to commence as soon as practicable following the Participant's
death.

          (b) Lump Sum Insurance Benefit Election. If the Participant elects the
lump sum benefit on the Participation Agreement and dies prior to termination of
his Service to the Company or Retirement, the Company shall promptly take any
action necessary to cause the death benefit provided under the Policy of life
insurance purchased by the Company hereunder on that Participant's life to be
paid. The amount of death benefit so payable to the Beneficiary shall be the
amount provided in Schedule B as a Pre-Retirement insurance death benefit. Any
additional benefit paid under the Policy shall be retained by the Company.

(5) Notwithstanding anything herein to the contrary the Participant shall be
entitled to the full amount which he would have been entitled to receive
hereunder if he were rendering Service to the Company on the Retirement Date, as
set forth in Section (2) of this Article II (or his Beneficiary shall be
entitled to the full amount set forth in Section (5) of this Article II as a
Survivor Income Benefit or as a Lump Sum Insurance Benefit in the event of the
death of a Participant prior to the Retirement Date) at such time as the
Company, its business or substantially all of its assets is sold, or acquired by
merger, consolidation or otherwise.

(6) Estimated Retirement Benefits and the Policy and Pre-Retirement death
benefits are set forth in Schedule B attached.

(7) Each Participant shall cooperate with the Company by furnishing any and all
information requested by the Company in order to facilitate the payment of
benefits hereunder, taking such physical examination as the Company may deem
necessary and taking such other relevant action as may be requested by the
Company. If a Participant refuses to cooperate, the Company shall have no
further obligation to the Participant under the Plan.

(8) For purposes of this Plan, a Participant or his Beneficiary shall have an
absolute right as an unsecured general creditor of the Company to payment of all
amounts and benefits including but not limited to Pre-Retirement Benefits.

                                   ARTICLE III


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                                 RETIREMENT DATE

The Company agrees that the Participant may terminate his Service because of
Retirement upon the earlier of (i) the first day of the month following his 65th
birthday, or (ii) upon such later date as may be acceptable to the Company.

                                   ARTICLE IV
                            DEATH PRIOR TO RETIREMENT

If the Participant dies prior to termination of his Service to the Company or
his Retirement Date, the Company will pay to his Beneficiary the amount provided
in Section (4) of Article II.

                                    ARTICLE V
                             DEATH AFTER RETIREMENT

Upon the death of the Participant after Retirement, the Company will pay to the
Participant's Beneficiary a sum equal to the balance of that amount which would
have been payable after Retirement, under the terms of Article II, Section (2).

                                   ARTICLE VI
                                   DISABILITY

If the Participant becomes disabled prior to Retirement, on the basis of any
standard established by the Board of Directors, and prior to termination of his
Service, the Company shall incur no obligation to commence benefit payments
immediately. In such event, the Company's obligation to pay benefits hereunder
will begin at Participant's reaching age 65. In the event of death of a disabled
Participant after commencement of retirement payments, the provisions of Article
V will apply. Notwithstanding the foregoing, in the event a disabled Participant
dies prior to Retirement, then the provisions of Article IV shall apply as
though at the time he died he was serving as a Participant who died prior to
Retirement.

                                   ARTICLE VII
                  NO GUARANTEE OF AMOUNT OF RETIREMENT BENEFITS

The Company does not guarantee the payment of the amount of projected retirement
benefits reflected on Schedule B, but does agree to pay an amount equal to the
Grossed-Up Cash Value as of the date of Retirement, or, in the event the
Participant elects 120 monthly payments under Article II, Section (2), the
projected Grossed-Up Cash Value increase over the next nine consecutive Policy
Years after the date of Retirement.

                                  ARTICLE VIII


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                             TERMINATION OF SERVICES

If the Company terminates the Service of the Participant, or if the Participant
terminates his Service prior to ten (10) years from the date hereof, any Company
obligation to the Participant shall cease. If the Company terminates the Service
of the Participant, or if the Participant terminates his Service after ten (10)
years from the date hereof, the Company shall pay the Participant or his
Beneficiary the termination benefits set forth in Section (4) of Article II.

                                   ARTICLE IX
                                   ASSIGNMENT

It is agreed that neither the Participant nor his Spouse nor any Beneficiary
shall have any right to convey, sell, assign, transfer, or otherwise convey the
right to receive any payments hereunder, which payments and rights thereto are
expressly declared to be nonassignable and nontransferable.

                                    ARTICLE X
                              RETENTION OF SERVICES

The benefits payable under this Agreement shall be independent of, and in
addition to, any other arrangement that may exist from time to time between the
parties hereto, or any other compensation payable by the Company to the
Participant. This Agreement shall not be deemed to constitute an employment
contract between the parties hereto, nor shall any provision hereof restrict the
right of the Company to terminate the Service of the Participant, or restrict
the right of the Participant to terminate his Service to the Company.

                                   ARTICLE XI
                              RIGHTS OF PARTICIPANT

The rights of the Participant under this Agreement and of any Beneficiary of the
Participant shall be solely those of an unsecured creditor of the Company. Any
Policy or any other asset acquired or held by the Company in connection with the
liabilities assumed by it hereunder shall not be deemed to be held under any
trust for the benefit of the Participant or his Beneficiary or to be a security
for the performance of the obligations of the Company, but shall be, and remain,
a general, unpledged, unrestricted asset of the Company.

                                   ARTICLE XII
                        OWNERSHIP OF INSURANCE CONTRACTS

The Company shall be the sole owner of any insurance contract or contracts
acquired on the life of a Participant, with incidents of ownership therein,
including, but not limited to, the right to cash and loan values, dividends, if
any, death benefits, and the right to termination thereof. The Participant shall
have the right to name on the Participation Agreement a Beneficiary for the
amount of the Pre-Retirement Death Benefit described herein.

                                  ARTICLE XIII


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                                 REORGANIZATION

The Company agrees that it will not merge or consolidate with any other
corporation or organization, or permit its business activities to be taken over
by another organization, unless and until the succeeding or continuing
corporation or other organization shall expressly assume the rights and
obligations of the Company herein set forth and as amended from time to time.
The Company further agrees that it will not cease business activities or
terminate its existence, other than as heretofore set forth in this paragraph,
without having made adequate provision for the fulfilling of its obligations
hereunder.

                                   ARTICLE XIV
                                   AMENDMENTS

This Plan may be revoked or be amended in whole or in part by a written
agreement signed by the Company and Participants.

                                   ARTICLE XV
                                 APPLICABLE LAW

This Plan shall be construed and governed in all respects under and by the laws
of the Commonwealth of Massachusetts.

                                   ARTICLE XVI
                                    HEADINGS

Headings and subheadings in this Agreement are inserted for convenience and
reference only and constitute no part of this Plan.

                                  ARTICLE XVII
                                  COUNTERPARTS

This Plan may be executed in an original and any number of counterparts, each of
which shall constitute an original of one and the same instrument.

                                  ARTICLE XVIII
                                CLAIMS PROCEDURE

Claims made under this plan shall be submitted to the Committee, which shall
establish such claims procedures as may be required by ERISA, to the extent
applicable, and other applicable laws. In the event of a dispute, the Company
and Participant shall submit the matter to binding arbitration to be conducted
under the rules of the American Arbitration Association in Boston,
Massachusetts. Each party shall have the right to designate an arbitrator and
the two arbitrators son designated shall select a third arbitrator.

                                   ARTICLE XIX


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                                 BINDING EFFECT

The provisions of this Plan shall be binding upon the parties. If any provisions
herein are deemed invalid or unenforceable, the remaining provisions shall
remain in full force and effect.

                                   ARTICLE XX
                                 EFFECTIVE DATE

The effective date of this Plan shall be April 4, 1995.

IN WITNESS WHEREOF, the said Company has caused this Plan to be signed in its
corporate name by its duly authorized officers.

                                        NATIONAL DENTEX CORPORATION


                                        By: /s/ WILLIAM M. MULLAHY
                                            ------------------------------------
                                            William M. Mullahy
                                            President & Chief Executive Officer


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