<PAGE>



                          [MILESTONE SCIENTIFIC LOGO]


July 30, 2003


Alan A. Creamer, CEO
Da Vinci Systems, Inc.
9885 Mesa Rim Road
Suite 216
San Diego, CA 92121



Dear Alan:

     This will confirm the agreement under which we will support your
development of a whitening system head (the "Product") and you will grant us
distribution rights to the Product and all pastes, gels or other disposables or
consumables ("Ancillary Products") and to your "Nova Cordless Curing Light" (the
"Curing Light", see Paragraph 3).

     1. We will reimburse you for the development cost of the Product, up to an
aggregate of $25,500, as follows: $7,000 for the conceptual design and prototype
engineering and $18,500 for the development of CAD files, tooling and
proto-typing. You will bear any costs in excess of these amounts. If, at any
time, you cease work on the development project or if development is not
completed within 28 days of the approval of Phase 1 (Conceptual Design and
Engineering) or by October 1, 2003, at the latest, then we shall have the option
to assume control of the development project at our expense. If we assume
control of the development project, you shall cooperate fully with us and shall
turn over to us all work previously completed, including the results of any
tests or submissions to focus groups. Any costs we incur, in excess of $25,500,
shall be credited against our obligations to pay for future units of Product,
Ancillary Products and the Curing Light.

     2. We shall be the exclusive worldwide distributor for the Product and
those Ancillary Products, if any, made exclusively for use with the Product. You
shall meet our requirements for Product and such Ancillary Products, including
related packaging, at a price per unit found in the attached Exhibit A. The
prices found in Exhibit A represent the maximum transfer price. Any reductions
from the product cost will be shared equally between Da Vinci and Milestone. All
orders will be filled within 30 days of a Purchase Order accompanied by a 50%
deposit. The remaining balance is to be paid net 30 days, F.O.B. manufacturer.
In connection with our activities as a distributor, you hereby grant us, a
limited, exclusive worldwide license, to use your intellectual property,
including any patents, in connection with the marketing and sale of the Product
and any Ancillary Products made exclusively for use with the Product.

     3. We shall also be a non-exclusive worldwide distributor of (i) Ancillary
Products not made exclusively for use with the Product and (ii) the Curing
Light. The Ancillary Products and the Curing Light

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[MILESTONE SCIENFITIC LOGO]                                       Page 2 of 5

shall be provided as attached in Exhibit A, provided that such price shall not
be higher than the lowest price at which such products are provided to other
distributors or dealers. The prices found in Exhibit A represent the maximum
transfer price. Any reductions from the product cost will be shared equally
between Da Vinci and Milestone. All orders will be filled within 30 days of a
Purchase Order accompanied by a 50% deposit. The remaining balance is to be paid
net 30 days, F.O.B. manufacturer.

     4. You will prepare and submit to us, within 15 days after the end of each
calendar quarter, a report setting forth the fully loaded manufacturing costs
for all products sold to us in the previous quarter, broken down by types of
products and a calculation of the prices due and/or collected on such products
for such period (the "Report"). The Report shall be certified by an officer of
Da Vinci to be true and correct. We shall have the right to audit your books and
records, to the extent necessary to determine compliance with this Section and
Sections 2 and 3, during normal business hours and upon reasonable notice. In
the event the audit reveals any discrepancies, the price paid for products shall
be retroactively readjusted to reflect the audit results and if the discrepancy
is more than 15% of your cost, you shall reimburse us for the cost of the audit.

     5. We shall have the right to use our own trademarks or brand names on the
Product and any Ancillary Product and you shall mark each unit and any packaging
utilized in connection therewith with such mark or marks as we direct.

     6. You will, at our reasonable request, provide us with reasonable
quantities of samples of the Product and Ancillary Products for the purpose of
performing quality control procedures and tests. We shall have the right to
inspect, not more than once every quarter, any of your manufacturing facilities
pertaining to the Product or Ancillary Products during regular business hours
and upon reasonable notice.

     7. You represent and warrant that all Product and Ancillary Product units
produced by you shall comply with all federal, state and local laws, ordinances,
rules, regulations and orders and shall be manufactured in accordance with the
FDA's GMP standards and comparable regulations of the European Community. You
further represent and warrant that all Product and Ancillary Product units
produced by you shall be of merchantable quality and free from defects. You
shall keep your manufacturing and packaging records and data for the Products in
accordance with G.M.P standards. We shall have access to such information upon
reasonable notice during business hours and we shall be entitled to make copies
thereof at our cost.

     8. You shall defend and indemnify us and hold us harmless against all
damages, claims, costs and expenses (including reasonable attorneys' fees)
arising out of or resulting from any product liability claims relating to
products produced by you. The obligation for indemnification set forth above
shall be contingent upon giving you timely notice of any claim or loss. You
shall carry and keep in force throughout the term of this Agreement
Comprehensive General Liability Insurance, including Products Liability combined
single limit in the amount of [$2,000,000], naming us as an additional insured
party:

     9. All data, inventions, discoveries, product designs, know-how, formulae,
studies, reports, documents, publications, software, computer programs, source
codes and the like relating to the Products or Ancillary Products, as well as
concepts and thoughts, shall be your sole and exclusive property.



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[MILESTONE SCIENFITIC LOGO]                                       Page 3 of 5

     10. You shall disclose to us any intellectual property relating to the
Product or Ancillary Products and assist us in applying for, maintaining, or
otherwise securing legal protection for the same. We agree to execute any
papers, documents or letters necessary to vest title in these materials in your
name. You shall take all appropriate action to defend the intellectual property
and any patents issued with respect thereto.

     11. In the event of any dispute between us, we agree that it shall be
resolved through arbitration in New York under the regulations of the American
Arbitration Association, within ninety (90) days following termination of this
Agreement. Any award rendered shall be final and conclusive upon the parties.
This Agreement shall be construed under the laws of the State of New York.

     12. At all times during the term of this Agreement, we shall act as
independent contractor, and neither the making of this Agreement nor the
performance of any of the provisions hereof shall be construed to make us your
agent or legal representative of Da Vinci for any purpose, nor shall this
Agreement be deemed to establish a joint venture or partnership. Neither of us
shall have the power or authority to bind or obligate the other party in any way
by any of its acts.

     13. All notices or other communications required or permitted to be given
hereunder shall be in writing and shall be valid and sufficient if dispatched by
registered mail, postage prepaid, addressed to the address indicated in this
Agreement or to such other address as the addressee shall have theretofore
furnished to the addressor as indicated below


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[MILESTONE SCIENFITIC LOGO]                                       Page 4 of 5


     14. This agreement represents the entire agreement between the parties and
may not be changed, amended or modified except by a writing signed by both
parties.

                                             Very truly yours,

                                             MILESTONE SCIENTIFIC INC.


                                             by:/s/ Leonard Osser
                                                -----------------------------
                                                    Leonard Osser, CEO
Accepted and agreed to the
30th day of July 2003

DA VINCI SYSTEMS, INC.


By: /s/ Alan Creamer
   -----------------
   Alan A. Creamer, CEO



By:___________________________
         Alan A. Creamer




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[MILESTONE SCIENFITIC LOGO]                                       Page 5 of 5



                                    EXHIBIT A

<TABLE>
<CAPTION>
PRODUCT                                                                    TRANSFER PRICE
<S>                                                                     <C>
Curing Light with head (Curing or Whitening):                                  $350.00
Whitening Head, Interproximal Tip and Diagnostic Tip                           $75.00
Amber Light Shields, minimum quantity 100                                      $22.00
Custom Barrier Sheaths                                                  $36.00 per box of 500
Per Patient Whitening Kit (In-office and take home included):                 $14.00
</TABLE>