Exhibit 10.1


                                                                  EXECUTION COPY

                           LOAN MODIFICATION AGREEMENT

     THIS LOAN MODIFICATION AGREEMENT (this "Agreement") is made as of March 29,
2007, by and between BANK OF AMERICA, N.A., successor by merger to Fleet
National Bank, a national banking association organized and existing under the
laws of the United States of America with an address at 100 Federal Street,
Boston, Massachusetts 02110 (the "Bank"), NATIONAL DENTEX CORPORATION, a
Massachusetts corporation, with an address at 526 Boston Post Road, Wayland, MA
01778 ("Dentex"), GREEN DENTAL LABORATORIES, INC., an Arkansas corporation, with
an address at 1099 Wilburn Road, Heber Springs, AR 72543 ("Green"), KELLER
GROUP, INCORPORATED, a Missouri corporation ("Keller"), KELLER LABORATORIES,
INCORPORATED - MIDWEST, a Missouri corporation ("Keller Midwest") and KELLER
LABORATORIES, INC. - SOUTHEAST, a Kentucky corporation ("Keller Southeast", and
with Dentex, Green, Keller and Keller Midwest, each a "Borrower", and
collectively the "Borrowers") each with an address at c/o National Dentex
Corporation, 526 Boston Post Road, Wayland, MA 01778.

     WHEREAS, reference is made to that certain loan arrangement (the "Loan
Arrangement") between the Bank and the Borrowers evidenced by, among any other
documents, instruments, and agreements, (i) that certain Second Amended and
Restated Loan Agreement dated November 7, 2006, by and among the Bank, Dentex,
and Green (the "Loan Agreement"); (ii) that certain Second Amended and Restated
First Line of Credit Note dated November 7, 2006, by and among the Bank and the
Borrowers; (iii) that certain Second Amended and Restated Second Line of Credit
Note dated November 7, 2006, by and among the Bank and the Borrowers; (iv) that
certain Amended and Restated Term Note, dated November 7, 2006, between the Bank
and the Borrowers; and (v) that certain Joinder Agreement dated as of January
11, 2007, by and among the Bank and the Borrowers; and

     WHEREAS, the Borrowers have requested that the Bank agree to the
modification of the Loan Documents to provide for daily automatic advances under
the First Line of Credit to bring Dentex's demand deposit account up to an
agreed upon target balance, and the Bank has so agreed, but only upon the terms
and conditions set forth hereinafter.

     NOW THERFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, it is hereby agreed by the Bank
and the Borrowers that the Loan Agreement and the other Loan Documents are
amended as follows:

1. Section 1, "The Credit Facility; Advances", is hereby amended by the addition
of the following text at the end of the Section 1(a)(i):

     "To the extent that there is availability under the First Line of Credit,
     AutoBorrow Advances may be used to fund the Target Balance in accordance
     with the terms and conditions of the AutoBorrow Service Agreement."



2. Section 1, "The Credit Facility; Advances", is hereby amended by the addition
of the following text at the end of the Section 1(b):

     "AutoBorrow Advances shall be made to Dentex in accordance with the terms
     of the AutoBorrow Service Agreement."

3. Section 2, "Interest; Payments; Fees; Borrowing", is hereby amended by the
addition of the following text at the end of Section 2(a):

     "AutoBorrow Advances shall bear interest at the LIBOR Lending Rate (having
     an Interest Period of 30 days) plus the Applicable Margin with respect
     thereto, as in effect from time to time."

4. Section 2, "Interest; Payments; Fees; Borrowing", is hereby amended by the
addition of the following text as an additional paragraph following Section
2(f)(viii):

     "(ix) Notice Requirements for AutoBorrow Advances. Any requirements in this
     Section 2 for notice to the Bank shall not be construed to apply to
     AutoBorrow Advances. AutoBorrow Advances shall be made automatically in
     accordance with the terms of the AutoBorrow Service Agreement. AutoBorrow
     Advances may be prepaid at any time and from time to time, without notice
     to the Bank, and without premium or penalty."

5. Section 4, "Definitions", is hereby amended by the addition of the following
definitions, which definitions shall be inserted as additional subsections at
the end of Section 4:

     (a)  "(oo) The term "AutoBorrow Advances" shall mean any advances made to
          the Borrowers under the terms of the AutoBorrow Service Agreement."

     (b)  "(pp) The term "Target Balance" shall have the meaning ascribed to
          this term in the AutoBorrow Service Agreement."

     (c)  "(qq) The term "AutoBorrow Service Agreement" shall mean that certain
          AutoBorrow Service Agreement dated as of May 12, 2004 by and between
          Dentex and the Bank, and/or any amendments, restatements or
          replacements thereof, as may be in effect from time to time."

6. Section 6, "Covenants", is hereby amended by deleting Section 6(u) in its
entirety and inserting in lieu thereof the following text:

          "(u) Maximum Consolidated Total Funded Debt to Consolidated EBITDA. As
               at the end of any fiscal quarter, the ratio of (a) Consolidated
               Total Funded Debt as of such date to (b) Consolidated EBITDA for
               the


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               period of four (4) consecutive fiscal quarters ending on the date
               of calculation (i) prior to and including December 31, 2007,
               shall not exceed 2.5:1.0 and (ii) thereafter shall not exceed
               2.0:1.0."

7. In all other respects, the Loan Agreement and the other Loan Documents are
hereby confirmed and ratified and all terms and provisions not amended hereby
shall remain in full force and effect. To the extent that any term and condition
of the Loan Agreement or any other Loan Document is inconsistent with the terms
and provisions hereof, the Loan Agreement and such other Loan Documents are
hereby amended to reflect the modifications and amendments set forth in this
Agreement.

8. To induce the Bank to enter into this Agreement, the Borrowers each represent
and warrant that (a) all the representations and warranties contained in the
Loan Documents, after giving effect to the amendments and modifications
contemplated hereby are true and correct on and as of the date hereof as though
made on and as of the date hereof; (b) as of the date hereof, the Borrowers have
no defenses, counterclaims, offsets or other claims against the Bank or any of
its officers, employees, agents, attorneys, predecessors, affiliates, or other
representatives of any nature, relating to the Loan Arrangement; and (c) no
default or breach under any of the Loan Documents after giving effect to the
amendments contemplated hereby, and no event which the passage of time or giving
of notice or both would constitute such a default or breach, exists on the date
hereof.

9. This Agreement does not constitute a discharge, release or waiver of any of
the Borrowers' obligations or liabilities under the Loan Documents, or any other
agreements to which the Bank and the Borrowers and any guarantor are parties,
all of which remain in full force and effect.

10. This Agreement and the rights and obligations of the parties hereunder shall
be deemed to be a document executed under seal and shall be construed and
interpreted in accordance with the laws of the Commonwealth of Massachusetts
(excluding the laws applicable to conflicts or choice of law).

11. This Agreement shall be binding upon and inure to the benefit of the parties
hereto, their respective administrators, successors and assigns. This Agreement
may only be amended in writing.

12. Capitalized terms used herein without definition shall have the meaning set
forth in the Loan Agreement.

                  [Remainder of page intentionally left blank.]
                           [Signature page to follow.]


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                 [Signature page to Loan Modification Agreement]

     IN WITNESS WHEREOF, the parties have caused this Agreement to be duly
executed as of the day and year first above written.

                                        NATIONAL
                                        DENTEX CORPORATION:


/s/ Jill Crosby                         By: /s/ Richard F. Becker, Jr.
- -------------------------------------       ------------------------------------
Witness:                                Name: Richard F. Becker, Jr.
                                        Title: Executive Vice President and
                                               Treasurer


                                        GREEN DENTAL LABORATORIES, INC.


/s/ Jill Crosby                         By: /s/ Richard F. Becker, Jr.
- -------------------------------------       ------------------------------------
Witness:                                Name: Richard F. Becker, Jr.
                                        Title: Assistant Treasurer


                                        KELLER GROUP, INCORPORATED


/s/ Jill Crosby                         By: /s/ Richard F. Becker, Jr.
- -------------------------------------       ------------------------------------
Witness:                                Name: Richard F. Becker, Jr.
                                        Title: Assistant Treasurer and Assistant
                                               Secretary


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           [Signature page to Loan Modification Agreement - continued]

                                        KELLER LABORATORIES, INCORPORATED -
                                        MIDWEST


/s/ Jill Crosby                         By: /s/ Richard F. Becker, Jr.
- -------------------------------------       ------------------------------------
Witness:                                Name: Richard F. Becker, Jr.
                                        Title: Assistant Treasurer and Assistant
                                               Secretary


                                        KELLER LABORATORIES, INC. - SOUTHEAST


/s/ Jill Crosby                         By: /s/ Richard F. Becker, Jr.
- -------------------------------------       ------------------------------------
Witness:                                Name: Richard F. Becker, Jr.
                                        Title: Assistant Treasurer and Assistant
                                               Secretary


                                        BANK OF AMERICA, N.A.


                                        By: /s/ Richard MacDonald
                                            ------------------------------------
                                        Name: Richard MacDonald
                                        Title: Vice President


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