<PAGE>

                                                                     Exhibit 4.3


                         REGENERATION TECHNOLOGIES, INC.

                     INCENTIVE STOCK OPTION GRANT AGREEMENT

                                  KEY EMPLOYEES



      This Grant Agreement (the "Agreement") is entered into this _____ day of
_________________, by and between REGENERATION TECHNOLOGIES, INC., a Delaware
corporation (the "Corporation"), and _____________ ("Grantee"), effective as of
the Grant Date as defined in Article 1 hereof.

      In consideration of the premises, mutual covenants and agreements herein,
the Corporation and the Grantee agree as follows:


                                  ARTICLE 1
                               GRANT OF OPTION


      SECTION 1.1 GRANT OF OPTION. The Corporation hereby grants to the Grantee,
pursuant to the provisions of the Regeneration Technologies, Inc. Omnibus Stock
Plan (the "Plan"), an incentive stock option to purchase shares of Common Stock,
par value of $0.001 per share, of the Corporation ("Stock"), subject to the
provisions of this Agreement (the "Option"). Unless stated otherwise herein,
capitalized terms in this Agreement shall have the same meaning as defined in
the Plan. Schedule A, attached hereto and incorporated herein, sets forth the
following terms of the Option:

      (i)   the date the Administrator approved the Option (the "Grant Date");

      (ii)  the  number of shares of Stock  which  the  Grantee  may  purchase
            under the Option;

      (iii) the exercise price per share (the "Exercise Price"); and

      (iv)  the date as of which the Option shall expire (the "Expiration
            Date"), at 5:00 p.m. Eastern Time, unless terminated earlier
            pursuant to other provisions of this Agreement.

      SECTION 1.2 LIMITATION ON TERM OF OPTION. Notwithstanding the foregoing,
in no event shall the Option expire later than 5:00 p.m. Eastern Time on the day
prior to the tenth (10th) anniversary of its Grant Date (or on the day prior to
the fifth (5th) anniversary of its Grant Date if the Grantee owns stock
possessing more than 10% of the total combined voting power of all classes of
stock of the Corporation or of any of its subsidiaries on the Grant Date).


                                  ARTICLE 2
                                   VESTING


      SECTION 2.1 VESTING SCHEDULE. Unless the Option terminates earlier
pursuant to other provisions of this Agreement, the Option shall vest and become
exercisable as provided in the following schedule:


<PAGE>

<TABLE>
<CAPTION>
                  Percentage of the Option
                  Vested and Exerciseable           As of
                  ------------------------          -----

<S>                                        <C>
                  0%                       Any date prior to the first
                                           anniversary of the Grant Date.

                  20%                      Any date on or after the first
                                           anniversary of the Grant Date.

                  40%                      Any date on or  after the second
                                           anniversary of the Grant Date

                  60%                      Any date on or after the third
                                           anniversary of the Grant Date

                  80%                      Any date on or after the fourth
                                           anniversary of the Grant Date

                  100%                     Any date on or  after the fifth
                                           anniversary of the Grant Date
</TABLE>



      SECTION 2.2 ACCELERATION OF VESTING. Unless the Option has earlier
terminated pursuant to the provision of the Agreement, vesting of the Option
shall be accelerated so that all unvested shares of Stock subject to the Option
shall become one hundred percent (100%) vested in the Grantee upon a Change of
Control. For purposes of this Agreement, the term "Change of Control" shall mean
(i) the sale of all or substantially all of the assets of the Corporation, (ii)
the sale of more than fifty percent (50%) of the outstanding common stock of the
Corporation in a non-public sale, (iii) the dissolution or liquidation of the
Corporation, or (iv) any merger, share exchange, consolidation or other
reorganization or business combination of the Corporation if immediately after
such transaction either (A) persons who were directors of the Corporation
immediately prior to such transaction do not constitute at least a majority of
the directors of the surviving entity, or (B) persons who hold a majority of the
voting capital stock of the surviving entity are not persons who held a majority
of the voting capital stock of the Corporation immediately prior to such
transaction.


                                  ARTICLE 3
                              EXERCISE OF OPTION


      SECTION 3.1 EXERCISABILITY OF OPTION. The Option is exercisable only if
it is vested and has not been terminated. If exercisable, the Option may be
exercised in whole or in part, subject to the conditions precedent described in
Section 3.3. Only Grantee and, after his death, his executor, personal
representative, or the person to whom the Option shall have been transferred by
will or the laws of descent and distribution, may exercise the Option.

      SECTION 3.2 MANNER OF EXERCISE. Grantee or any other person exercising
the Option may do so only by delivering written notice thereof to the
Administrator. Such notice shall be in the form as attached hereto, unless the
Administrator requires otherwise. Notwithstanding the foregoing, the Option may
not be exercised at any one time as to fewer than five (5) Shares or, if less,
such number of Shares as to which the Option is then exercisable. Such notice
shall be accompanied by full payment of the Exercise Price. Payment of the
Exercise Price shall be made in cash, provided that the Administrator may
authorize a payment of the Exercise Price to be



                                      -2-
<PAGE>

made, in whole or in part, by such other means as the Administrator may
prescribe at the time of exercise. The Option may be exercised only in multiples
of whole Shares and no fractional Shares shall be issued. If the Common Stock is
registered under Section 12 of the Securities Exchange Act of 1934, as amended,
the Exercise Price may be paid, in whole or in part, subject to such limitations
as the Administrator may determine, by delivery of a properly executed exercise
notice, together with irrevocable instructions: (i) to a brokerage firm
designated by the person exercising the Option and approved by the Administrator
to deliver promptly to the Corporation the aggregate amount of sale or loan
proceeds to pay the Exercise Price and any withholding tax obligations that may
arise in connection with the exercise, and (ii) to the Corporation to deliver
the certificates for such purchased Shares directly to such brokerage firm.

      SECTION 3.3 ISSUANCE OF SHARES UPON EXERCISE. Upon exercise of the Option
and payment of the Exercise Price, the Corporation shall issue to Grantee the
number of Shares so paid for, in the form of fully paid and nonassessable Common
Stock. If the Common Stock is not yet registered under Section 12 of the
Securities Exchange Act of 1934, as amended, the Grantee shall be required to
execute and deliver, as a condition precedent to the exercise of the option and
the issuance of the Shares to the Grantee, a stockholder agreement and/or stock
restriction agreement which shall contain certain stock restrictions, including
but not limited to a waiver of inspection rights, proxy voting, limitations on
transfer and other restrictions. The Grantee's stock certificates shall be held
in escrow by the Corporation during the period that the shares are subject to
restriction. The stock certificates for any Shares issued hereunder shall,
unless such Shares are registered, bear a legend restricting transferability of
such Shares and referencing the stockholder agreement and stock restriction
agreement.


                                  ARTICLE 4
                            TERMINATION OF OPTION


      SECTION 4.1 TERMINATION, IN GENERAL. The Option granted hereby shall
terminate and be of no force or effect after the Expiration Date set forth on
Schedule A, unless terminated prior to such time as provided below.
Notwithstanding anything contained herein, vesting of the Option pursuant to
Section 2.1 shall cease upon the Grantee's termination of employment by, or
service to, the Corporation, unless otherwise agreed by the Corporation in
writing.


      SECTION 4.2 TERMINATION OF EMPLOYMENT OR SERVICE OR FOR REASON OTHER THAN
DEATH OR DISABILITY. Unless the Option has earlier terminated pursuant to the
provisions of the Agreement, the Option shall terminate in its entirety,
regardless of whether the Option is vested in whole or in part, thirty (30) days
after the date the Grantee is no longer employed by, or not in the service of,
the Corporation and its Affiliates for any reason other than the Grantee's death
or Disability. Notwithstanding the foregoing, the Option shall terminate in its
entirety, regardless of whether the Option is vested in whole or in part, upon
termination of the employment or service of the Grantee by the Corporation or an
Affiliate for "Cause".


      If the Grantee is a party to a written employment agreement or service
agreement with the Corporation or an Affiliate then currently in effect which
contains a definition of "cause", "termination for cause" or words of similar
import, whether such Grantee is terminated for "Cause" pursuant to this Section
4.2 shall be determined according to the terms of and in a manner consistent
with the provisions of such written agreement. If the Grantee is not party to




                                      -3-
<PAGE>

such a written employment agreement or service agreement with the Corporation or
an Affiliate, then for purposes of this Section 4.2, "Cause" shall mean (a) the
conviction of the Grantee of, or the entry of a pleading of guilty or nolo
contendere by the Grantee to, any felony or any crime involving moral turpitude,
(b) willful misconduct in connection with the Grantee's duties, willful failure
to follow the directions of the Grantee's supervisor or supervisors, or willful
failure to perform his or her responsibilities in the best interest of the
Corporation, except in cases involving the mental or physical incapacity or
disability of the Grantee, or (c) in the sole judgment of the President of the
Corporation, the Grantee has acted or is acting in a manner that is not in the
best interest of the Corporation or its employees, including but not limited to,
disparaging the Corporation or its products or engaging in harassment or other
inappropriate behavior directed towards employees of the Corporation. "Willful
misconduct" and "willful failure to perform" shall not include actions or
inactions on the part of the Grantee which were taken or not taken in good faith
by the Grantee. The good faith determination by the Administrator of whether the
Grantee's employment or service was terminated by the Corporation for "Cause"
shall be final and binding for all purposes hereunder.

      SECTION 4.3 UPON GRANTEE'S DEATH. Unless the Option has earlier terminated
pursuant to the provisions of the Agreement, upon the Grantee's death the
Grantee's executor, personal representative, or the person(s) to whom the Option
shall have been transferred by will or the laws of descent and distribution, may
exercise all or any part of the outstanding Option with respect to the shares of
Stock as to which the Option is vested as of the Grantee's date of death,
provided such exercise occurs within six (6) months after the date of the
Grantee's death, but not later than the Expiration Date of the Option. Unless
sooner terminated, the Option shall terminate upon the expiration of such six
(6) month period.

      SECTION 4.4 TERMINATION OF EMPLOYMENT OR SERVICE BY REASON OF DISABILITY.
Unless the Option has earlier terminated pursuant to the provisions of the
Agreement, in the event that the Grantee ceases, by reason of Disability, to be
an employee of or in the service of the Corporation or an Affiliate, the
outstanding Option may be exercised in whole or in part with respect to the
shares of Stock as to which the Option is vested as of the date of the Grantee's
termination of employment or service due to Disability at any time within six
(6) months after the date of such termination, but not later than the Expiration
Date of the Option. Unless sooner terminated, the Option shall terminate upon
the expiration of such six (6) month period.

      For purposes of this Agreement, Disability shall mean the inability to
engage in any substantial gainful activity by reason of any medically
determinable physical or mental impairment which can be expected to result in
death or which has lasted or can be expected to last for a continuous period of
not less than twelve (12) months. The Administrator may require such proof of
Disability as the Administrator in its sole discretion deems appropriate and the
Administrator's determination as to whether the Grantee is Disabled shall be
final and binding on all parties concerned.

      SECTION 4.5 LEAVE OF ABSENCE. For purposes of this Agreement, the
Grantee's employment or service with the Corporation or an Affiliate shall not
be deemed to terminate if the Grantee takes any military leave, sick leave, or
other bona fide leave of absence approved by the Administrator of ninety (90)
days or less. In the event of a leave in excess of ninety (90) days, the
Grantee's employment or service shall be deemed to terminate on the ninety-first
(91st)



                                      -4-
<PAGE>

day of the leave unless the Grantee's right to re-employment with the
Corporation or Affiliate remains guaranteed by statute or contract.
Notwithstanding the foregoing, unless otherwise determined by the Administrator
(or required by law), a leave of absence shall not be treated as employment or
service for purposes of vesting in additional shares of Stock during such leave
pursuant to Section 2.1 of this Agreement.


                                  ARTICLE 5
                      ADJUSTMENTS; BUSINESS COMBINATIONS


      SECTION 5.1 ADJUSTMENTS FOR EVENTS AFFECTING COMMON STOCK. In the event of
changes in the Common Stock of the Corporation by reason of any stock dividend,
split-up, recapitalization, merger, consolidation, business combination or
exchange of shares and the like, the Administrator shall, in its discretion,
make appropriate adjustments to the number, kind and price of shares covered by
this Option, and shall, in its discretion and without the consent of the
Grantee, make any other adjustments in this Option, including but not limited to
reducing the number of shares subject to the Option or providing or mandating
alternative settlement methods such as settlement of the Option in cash or in
shares of Common Stock or other securities of the Corporation or of any other
entity, or in any other matters which relate to the Option as the Administrator
shall, in its sole discretion, determine to be necessary or appropriate.

      SECTION 5.2 POOLING OF INTERESTS TRANSACTION. Notwithstanding anything in
the Plan or this Agreement to the contrary and without the consent of the
Grantee, the Administrator, in its sole discretion, may make any modifications
to the Option, including but not limited to cancellation, forfeiture, surrender
or other termination of the Option in whole or in part regardless of the vested
status of the Option, in order to facilitate any business combination that is
authorized by the Board to comply with requirements for treatment as a pooling
of interests transaction for accounting purposes under generally accepted
accounting principles.

      SECTION 5.3 ADJUSTMENTS FOR UNUSUAL EVENTS. The Administrator is
authorized to make, in its discretion and without the consent of the Grantee,
adjustments in the terms and conditions of, and the criteria included in, the
Option in recognition of unusual or nonrecurring events affecting the
Corporation, or the financial statements of the Corporation or any Subsidiary,
or of changes in applicable laws, regulations, or accounting principles,
whenever the Administrator determines that such adjustments are appropriate in
order to prevent dilution or enlargement of the benefits or potential benefits
intended to be made available under the Option or the Plan.

      SECTION 5.4 BINDING NATURE OF ADJUSTMENTS. Adjustments under this Article
5 will be made by the Administrator, whose determination as to what adjustments,
if any, will be made and the extent thereof will be final, binding and
conclusive. No fractional shares will be issued pursuant to this Option on
account of any such adjustments.



                                      -5-
<PAGE>

                                  ARTICLE 6
                                MISCELLANEOUS


      SECTION 6.1 NON-GUARANTEE OF EMPLOYMENT. Nothing in the Plan or this
Agreement shall alter the employment status of the Grantee, nor be construed as
a contract of employment between the Corporation (or an Affiliate) and the
Grantee, or as a contractual right of the Grantee to continue in the employ or
service of the Corporation (or an Affiliate), or as a limitation of the right of
the Corporation (or an Affiliate) to discharge the Grantee at any time with or
without cause or notice.

      SECTION 6.2 NO RIGHTS OF STOCKHOLDER. The Grantee shall not have any of
the rights of a stockholder with respect to the shares of Stock that may be
issued upon the exercise of the Option until such shares of Stock have been
issued upon the due exercise of the Option, subject to and in accordance with
the provisions of Section 3.3. No adjustment shall be made for dividends or
distributions or other rights for which the record date is prior to the date
such certificate or certificates are issued.

      SECTION 6.3 NATURE OF OPTION. The Option is intended to be a stock option
that qualifies as an incentive stock option ("Incentive Stock Option") within
the meaning of Section 422 of the Internal Revenue Code of 1986, as amended, to
the fullest extent permitted within the limit set forth under Section 422(d) of
the Code, and this Agreement shall be so construed. The aggregate fair market
value (determined as of the Grant Date) of the shares of Stock with respect to
which all Incentive Stock Options first become exercisable by the Grantee in any
calendar year under the Plan or any other plan of the Corporation (and its
parent and subsidiary corporations, as may exist from time to time) may not
exceed $100,000 or such other amount as may be permitted from time to time under
Section 422 of the Code. To the extent that such aggregated fair market value
shall exceed $100,000 or other applicable amount in any calendar year, such
stock options shall be treated as nonqualified stock options with respect to the
amount of the aggregate fair market value thereof that exceeds the Section
422(d) limit. For this purpose, the Incentive Stock Options will be taken into
account in the order in which they were granted. In such case, the Corporation
may designate the shares of Stock that are to be treated as stock acquired
pursuant to a nonqualified stock option by issuing separate certificates for
such shares and identifying the certificates as such in the stock transfer
records of the Corporation.

      SECTION 6.4 NOTICE OF DISQUALIFYING DISPOSITION. If the Grantee makes a
disposition (as that term is defined in Section 424(c) of the Code) of any
shares of Stock acquired pursuant to the exercise of this Option within two (2)
years of the Grant Date or within one (1) year after the shares of Stock are
transferred to the Grantee, the Grantee shall notify the Administrator of such
disposition in writing within thirty (30) days of the disposition.

      SECTION 6.5 THE CORPORATION'S RIGHTS. The existence of this Option shall
not affect in any way the right or power of the Corporation or its stockholders
to make or authorize any or all adjustments, recapitalizations, reorganizations
or other changes in the Corporation's capital structure or its business, or any
merger or consolidation of the Corporation, or any issue of bonds, debentures,
preferred or other stocks with preference ahead of or convertible into, or
otherwise affecting the Stock or the rights thereof, or the dissolution or
liquidation of the



                                      -6-
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Corporation, or any sale or transfer of all or any part of the Corporation's
assets or business, or any other corporate act or proceeding, whether of a
similar character or otherwise.

      SECTION 6.6 WITHHOLDING OF TAXES. The Corporation or any Affiliate shall
have the right to deduct from any compensation or any other payment of any kind
(including withholding the issuance of shares of Stock) due the Grantee the
amount of any foreign, federal, state or local taxes required by law to be
withheld as the result of the exercise of the Option or the lapsing of any
restriction with respect to any shares of Stock acquired on exercise of the
Option; provided, however, that the value of the shares of Stock withheld may
not exceed the statutory minimum withholding amount required by law. In lieu of
such deduction, the Administrator may require the Grantee to make a cash payment
to the Corporation or an Affiliate equal to the amount required to be withheld.
If the Grantee does not make such payment when requested, the Corporation may
refuse to issue any Stock certificate under the Plan until arrangements
satisfactory to the Administrator for such payment have been made.

      SECTION 6.7 GRANTEE. Whenever the word "Grantee" is used in any provision
of this Agreement under circumstances where the provision should logically be
construed to apply to the estate, personal representative or beneficiary to whom
this Option may be transferred by will or by the laws of descent and
distribution, the word "Grantee" shall be deemed to include such person.

      SECTION 6.8 NONTRANSFERABILITY OF OPTION. The Option shall be
nontransferable otherwise than by will or the laws of descent and distribution
and during the lifetime of the Grantee, the Option may be exercised only by the
Grantee or, during the period the Grantee is under a legal disability, by the
Grantee's guardian or legal representative. Except as provided in the preceding
sentence, the Option may not be assigned, transferred, pledged, hypothecated or
disposed of in any way (whether by operation of law or otherwise) and shall not
be subject to execution, attachment or similar process.

      SECTION 6.9 NOTICES. All notices and other communications made or given
pursuant to the Agreement shall be in writing and shall be sufficiently made or
given if hand delivered or mailed by certified mail, addressed to the Grantee at
the address contained in the records of the Corporation, or addressed to the
Administrator, care of the Corporation for the attention of its Secretary at its
principal office or, if the receiving party consents in advance, transmitted and
received via telecopy or via such other electronic transmission mechanism as may
be available to the parties.

      SECTION 6.10 ENTIRE AGREEMENT; MODIFICATION. This Agreement contains the
entire agreement between the parties with respect to the subject matter
contained herein and may not be modified, except as provided in the Plan or in a
written document signed by each of the parties hereto. Any oral or written
agreements, representations, warranties, written inducements, or other
communications made prior to the execution of the Agreement shall be void and
ineffective for all purposes.

      SECTION 6.11 CONFORMITY WITH PLAN. This Agreement is intended to conform
in all respects with, and is subject to all applicable provisions of, the Plan,
which is incorporated herein by reference. Inconsistencies between this
Agreement and the Plan shall be resolved in



                                      -7-
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accordance with the terms of the Plan. In the event of any ambiguity in the
Agreement or any matters as to which the Agreement is silent, the Plan shall
govern. A copy of the Plan is available upon request to the Administrator.

      SECTION 6.12 GOVERNING LAW. This Agreement shall be governed by and
construed in accordance with the laws of the State of Delaware, other than the
conflict of laws principles thereof.

      SECTION 6.13 HEADINGS. The headings in the Agreement are for reference
purposes only and shall not affect the meaning or interpretation of the
Agreement.


                            [SIGNATURES ON NEXT PAGE]




                                      -8-
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      IN WITNESS WHEREOF, the Corporation has caused this Agreement, which shall
be effective as of the Grant Date, to be executed by its duly authorized
officer, and the Grantee has hereunto set his hand and seal.

ATTEST:                                   REGENERATION TECHNOLOGIES,
                                          INC.


                                          By:
-------------------------------              ---------------------------------
                                              Jamie M. Grooms, President/CEO
                                          Date:
                                               -------------------------------



WITNESS:                                  GRANTEE


-------------------------------           ------------------------------------
                                          Name
                                          Date:
                                                ------------------------------

                                          SSN: (REQUIRED)
                                                          --------------------






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                                   SCHEDULE A

                       OF REGENERATION TECHNOLOGIES, INC.

                     INCENTIVE STOCK OPTION GRANT AGREEMENT





NAME OF GRANTEE:

DATE OPTION WAS APPROVED
BY PLAN ADMINISTRATOR:


NUMBER OF SHARES:                   shares of Regeneration
                                Technologies, Inc. Common Stock



EXERCISE PRICE PER SHARE:       $    per share



EXPIRATION DATE:





<PAGE>



                                  EXERCISE FORM


Stock Option Plan Administrator
c/o Office of the Corporate Secretary
Regeneration Technologies, Inc.
One Innovation Drive
Alachua, Florida 32615

Gentlemen:


      I hereby exercise the Option granted to me on __________, _____ by
Regeneration Technologies, Inc. (the "Corporation"), subject to all the terms
and provisions thereof and of the Regeneration Technologies, Inc. Omnibus Stock
Plan (the "Plan"), and notify you of my desire to purchase ____________ shares
of Common Stock of the Corporation at a price of $[______] per share pursuant to
the exercise of said Option.









Total Amount Enclosed:  $__________



Date:
     ---------------------------    ------------------------------------
                                    NAME



                                    Received by Regeneration Technologies,
                                    Inc. on:
                                                            ,
                                    ------------------------  ------
                                    By:
                                        --------------------------