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                                                                     EXHIBIT 4.4

                           THIRD AMENDED AND RESTATED
                         SUBSIDIARIES PLEDGE AGREEMENT


              THIRD AMENDED AND RESTATED PLEDGE AGREEMENT, dated as of July 1,
1998, made by each of the undersigned corporations (each, a "Pledgor", and
collectively, the "Pledgors") in favor of The Chase Manhattan Bank, as
Administrative Agent (in such capacity, the "Administrative Agent"), for the
banks and other financial institutions (the "Lenders") from time to time
parties to the Second Amended and Restated Credit Agreement, dated as of April
25, 1997 (as amended, supplemented or otherwise modified from time to time, the
"Credit Agreement"), among Sybron International Corporation, a Wisconsin
corporation ("the Parent"), Ormco Corporation, a Delaware corporation
("Ormco"), Kerr Corporation, a Delaware corporation ("Kerr"), Nalge Nunc
International Corporation, a Delaware corporation ("NNI"), Erie Scientific
Company, a Delaware corporation ("Erie"), Barnstead Thermolyne Corporation, a
Delaware corporation ("Barnstead"; Ormco, Kerr, NNI, Erie and Barnstead are
collectively referred to herein as the "Subsidiary Borrowers"), the Lenders,
the Administrative Agent and Chase Securities Inc., as arranger.


                              W I T N E S S E T H:


              WHEREAS, each Pledgor is the legal and beneficial owner of the
shares of Pledged Stock (as hereinafter defined) hereby pledged by such
Pledgor;

              WHEREAS, each Pledgor is the legal and beneficial owner of each
of the Pledged Notes (as hereinafter defined) hereby pledged by such Pledgor;
and

              NOW, THEREFORE, in consideration of the premises and to induce
the Administrative Agent and the Lenders to enter into the  Credit Agreement
and to induce the Lenders to make their respective extensions of credit to the
Parent and Subsidiary Borrowers under the Credit Agreement, each Pledgor hereby
agrees with the Administrative Agent, for the ratable benefit of the Lenders,
as follows:

              1.     Defined Terms.  (a)    Unless otherwise defined herein,
terms defined in the Credit Agreement or the Subsidiaries Guarantee and used
herein are so used as so defined.

              (b)    The following terms shall have the following meanings:

              "Agreement":  this Second Amended and Restated Pledge Agreement,
       as the same may be amended, modified or otherwise supplemented from time
       to time.

              "Code":  the Uniform Commercial Code from time to time in effect
       in the State of New York.
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              "Collateral":  the Pledged Stock, the Pledged Notes and all
       Proceeds.

              "Issuers":  the collective reference to the companies identified
       on Schedule 1 hereto as the issuers of the Pledged Stock.

              "Obligations" means (a) as to any Pledgor, all of its obligations
       and liabilities (i) under the Subsidiaries Guarantee, subject to the
       limitations on liability contained therein and (ii) to any Lender or an
       Affiliate of any Lender under or in connection with any Interest Rate
       Agreement or foreign exchange contract and (b) without duplication, as
       to any Pledgor which is a Subsidiary Borrower, the unpaid principal of
       and interest on (including, without limitation, interest accruing after
       the maturity of the Loans made to such Pledgor and interest accruing on
       or after the filing of any petition in bankruptcy, or the commencement
       of any insolvency, reorganization or like proceeding, relating to such
       Pledgor, whether or not a claim for post-filing or post-petition
       interest is allowed in such proceeding) the Notes of such Pledgor and
       all other obligations and liabilities of such Pledgor to the
       Administrative Agent or to the Lenders, whether direct or indirect,
       absolute or contingent, due or to become due, or now existing or
       hereafter incurred, which may arise under, out of, or in connection
       with, the Credit Agreement, the Notes, any other Loan Document and any
       other document made, delivered or given in connection herewith or
       therewith, whether on account of principal, interest, reimbursement
       obligations, fees, indemnities, costs, expenses (including, without
       limitation, all fees and disbursements of counsel to the Administrative
       Agent or to the Lenders) or otherwise; where the context requires,
       "Obligations" refers to the Obligations (as defined herein) of each and
       every Pledgor.

              "Obligors":  the collective reference to the companies identified
       on Schedule 2 hereto, as such Schedule may be amended from time to time.

              "Pledged Notes":  the promissory note or notes of the Obligors
       identified on Schedule 2, together with all substitutes, replacements or
       refinancings thereto that may be issued or granted by any Obligor to any
       Pledgor while this Agreement is in effect.

              "Pledged Stock":  the shares of capital stock or other equity
       interests listed on Schedule 1 hereto, together with all stock
       certificates, options or rights of any nature whatsoever that may be
       issued or granted by any Issuer to any Pledgor in respect of the Pledged
       Stock while this Agreement is in effect.

              "Proceeds":  all "proceeds" as such term is defined in Section 9-
       306(1) of the Uniform Commercial Code in effect in the State of New York
       on the date hereof and, in any event, shall include, without limitation,
       all dividends or other income from the Pledged Stock and the Pledged
       Notes, collections thereon or distributions with respect thereto.

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

              (c)    The words "hereof," "herein" and "hereunder" and words of
similar import when used in this Agreement shall refer to this Agreement as a
whole and not to any particular
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provision of this Agreement, and Section and paragraph references are to this
Agreement unless otherwise specified.

              (d)  The meanings given to terms defined herein shall be equally
applicable to both the singular and plural forms of such terms.

              2.     Pledge; Grant of Security Interest.  Each Pledgor hereby
delivers to the Administrative Agent, for the ratable benefit of the Lenders,
all of the Pledged Stock (except such Pledged Stock which is not certificated)
and the Pledged Notes listed with its name on Schedule 1 or Schedule 2 hereto,
as the case may be, and hereby grants to the Administrative Agent, for the
ratable benefit of the Lenders, a first security interest in the Collateral
granted by such Pledgor, as collateral security for the prompt and complete
payment and performance when due (whether at the stated maturity, by
acceleration or otherwise) of the Obligations of such Pledgor.

              3.     Stock Powers and Allonges.  (a)  Concurrently with the
delivery to the Administrative Agent of each certificate representing one or
more shares of Pledged Stock to the Administrative Agent, the relevant Pledgor
shall deliver an undated stock power covering such certificate, duly executed
in blank by such Pledgor with, if the Administrative Agent so requests,
signature guaranteed.

              (b)    Concurrently with the delivery to the Administrative Agent
of each note representing one of the Pledged Notes, the relevant Pledgor shall
deliver executed allonges endorsing such notes to "Bearer" with, if the
Administrative Agent so requests, signature guaranteed.

              4.     Representations and Warranties.  Each Pledgor represents
and warrants that:

              (a)    except as set forth on Schedule 1 hereto, the shares of
       Pledged Stock of such Pledgor constitute all the issued and outstanding
       shares of all classes of the capital stock of the Issuers thereof;
       provided, however, that the parties acknowledge that the capital stock
       of LMD Laboratories, Inc., an indirect subsidiary of Erie with tangible
       assets of less than $1,000,000 and total assets of less than $2,000,000,
       and of Lab Acquisition Co., a direct subsidiary of Barnstead having no
       assets, have not been pledged hereunder.

              (b)    the Pledged Notes of such Pledgor constitute all of the
       issued and outstanding promissory notes payable by the Parent and the
       direct and indirect Subsidiaries of the Parent (other than such Pledgor)
       to such Pledgor;

              (c)  all the shares of such Pledged Stock have been duly and
       validly issued and are fully paid and nonassessable; and each of such
       Pledged Notes has been duly and validly issued and is the legal, valid
       and binding obligation of the maker thereof, enforceable in accordance
       with its terms, except as affected by bankruptcy, insolvency, fraudulent
       conveyance, reorganization, moratorium and other similar laws relating
       to or affecting creditors' rights generally, general equitable
       principles (whether considered in a proceeding in equity or at law) and
       an implied covenant of good faith and fair dealing;
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              (d)    such Pledgor is the record and beneficial owner of, and
       has good and marketable title to, such Pledged Stock and Pledged Notes,
       free of any and all Liens or options in favor of, or claims of, any
       other Person, except the security interest created by this Agreement;

              (e)    upon delivery to the Administrative Agent of the stock
       certificates evidencing such Pledged Stock (or in the case of certain
       Issuers organized under foreign jurisdictions, the deed or other
       document evidencing such Pledged Stock) and upon delivery to the
       Administrative Agent of such Pledged Notes, the security interest
       created by this Agreement will constitute a valid, perfected first
       priority security interest in the Collateral granted by such Pledgor,
       enforceable in accordance with its terms against all creditors of such
       Pledgor and any Persons purporting to purchase any Collateral from such
       Pledgor, except as affected by bankruptcy, insolvency, fraudulent
       conveyance, reorganization, moratorium and other similar laws relating
       to or affecting creditors' rights generally, general equitable
       principles (whether considered in a proceeding in equity or at law) and
       an implied covenant of good faith and fair dealing;

              (f)    such Pledgor has obtained from each Issuer and has
       delivered to the Administrative Agent an Acknowledgement and Consent,
       substantially in the form attached hereto as Annex A, executed by each
       such Issuer; and

              (g)    no consent or authorization of, filing with or other act
       by or in respect of any Person is required in connection with the
       execution, delivery, performance, validity or enforceability of such
       Pledged Notes, and such Pledgor has fully performed all its obligations
       under such Pledged Notes.

              5.     Covenants.  Each Pledgor covenants and agrees with the
Administrative Agent and the Lenders that, from and after the date of this
Agreement until the Obligations are paid in full and the Commitments are
terminated:

              (a)    If such Pledgor shall, as a result of its ownership of any
       Pledged Stock, become entitled to receive or shall receive any stock
       certificate (including, without limitation, any certificate representing
       a stock dividend or a distribution in connection with any
       reclassification, increase or reduction of capital or any certificate
       issued in connection with any reorganization), option or rights, whether
       in addition to, in substitution of, as a conversion of, or in exchange
       for any shares of any Pledged Stock, or otherwise in respect thereof,
       such Pledgor shall accept the same as the agent of the Administrative
       Agent and the Lenders, hold the same in trust for the Administrative
       Agent and the Lenders and deliver the same forthwith to the
       Administrative Agent in the exact form received, duly indorsed by such
       Pledgor to the Administrative Agent, if required, together with an
       undated stock power covering such certificate duly executed in blank by
       such Pledgor and with, if the Administrative Agent so requests,
       signature guaranteed, to be held by the Administrative Agent, subject to
       the terms hereof, as additional collateral security for the Obligations
       of such Pledgor.  Any sums paid to such Pledgor upon or in respect of
       any Pledged Stock or
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                                                                               5



       any Pledged Notes upon the liquidation or dissolution of any Issuer or
       any Obligor, as the case may be, shall be paid over to the
       Administrative Agent to be held by it hereunder as additional collateral
       security for the Obligations of such Pledgor, and in case any
       distribution of capital or payment of principal shall be made to such
       Pledgor on or in respect of any Pledged Stock or any Pledged Notes or
       any property shall be distributed upon or with respect to any Pledged
       Stock or any Pledged Notes pursuant to the recapitalization or
       reclassification of the capital of any Issuer or any Obligor, as the
       case may be, or pursuant to the reorganization thereof, the property so
       distributed to such Pledgor shall be delivered to the Administrative
       Agent to be held by it hereunder as additional collateral security for
       the Obligations of such Pledgor.  If any sums of money or property so
       paid or distributed in respect of any Pledged Stock or any Pledged Notes
       shall be received by such Pledgor, such Pledgor shall, until such money
       or property is paid or delivered to the Administrative Agent, hold such
       money or property in trust for the Lenders, segregated from other funds
       of such Pledgor, as additional collateral security for the Obligations
       such Pledgor.  Notwithstanding the foregoing, in no event shall more
       than 65% of the issued and outstanding shares of stock, or any property
       distributed in respect thereof, of any Issuer which is a Controlled
       Foreign Corporation constitute collateral security for the Obligations.

              (b)    Without the prior written consent of the Administrative
       Agent, no Pledgor shall (1) vote to enable, or take any other action to
       permit, any Issuer to issue any stock or other equity securities of any
       nature or to issue any other securities convertible into or granting the
       right to purchase or exchange for any stock or other equity securities
       of any nature of such Issuer (2) sell, assign, transfer, exchange, or
       otherwise dispose of, or grant any option with respect to, the
       Collateral, or (3) create, incur or permit to exist any Lien or option
       in favor of, or any claim of any Person with respect to, any of the
       Collateral, or any interest therein, except for the security interests
       created by this Agreement and Liens permitted by the Credit Agreement.
       Each Pledgor will defend the right, title and interest of the
       Administrative Agent and the Lenders in and to the Collateral against
       the claims and demands of all Persons whomsoever.

              (c)    At any time and from time to time, upon the written
       request of the Administrative Agent to a Pledgor, and at the sole
       expense of such Pledgor, such Pledgor will promptly and duly execute and
       deliver such further instruments and documents and take such further
       actions as the Administrative Agent may reasonably request for the
       purposes of obtaining or preserving the full benefits of this Agreement
       and of the rights and powers herein granted.  If any amount payable
       under or in connection with any of the Collateral shall be or become
       evidenced by any promissory note, other instrument or chattel paper,
       such note, instrument or chattel paper shall be immediately delivered to
       the Administrative Agent, duly endorsed in a manner satisfactory to the
       Administrative Agent, to be held as Collateral pursuant to this
       Agreement.

              (d)  Each Pledgor shall pay, and save the Administrative Agent
       and the Lenders harmless from, any and all liabilities with respect to,
       or resulting from any delay in paying, any and all stamp, excise, sales
       or other taxes which may be payable or determined to be
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       payable with respect to any of the Collateral granted by such Pledgor or
       in connection with any of the transactions contemplated by this
       Agreement.

              (e)    Each Pledgor will not (i) amend, modify, terminate or
       waive any provision of any Pledged Note in any manner materially adverse
       to the interests of the Administrative Agent or the Lenders, (ii) fail
       to exercise promptly and diligently each and every material right which
       it may have under any Pledged Note where such failure could reasonably
       be expected to have an adverse affect on the interests of the
       Administrative Agent or the Lenders or (iii) fail to deliver to the
       Administrative Agent a copy of each material demand, notice or document
       received by it relating in any way to any Pledged Note.

              (f)    Without the prior written consent of the Administrative
       Agent, no Pledgor will grant any extension (other than, so long as no
       Default or Event of Default shall exist, extensions granted in
       accordance with prudent business judgment) of the time of payment of any
       Pledged Note, compromise, compound or settle the same for less than the
       full amount thereof, release, wholly or partially, any Person liable for
       the payment thereof, or allow any credit or discount whatsoever thereon.

              (g)    Each Pledgor shall deliver to the Administrative Agent, in
       the exact form received, to be held by the Administrative Agent, subject
       to the terms hereof, as additional collateral security for the
       Obligations of such Pledgor any additional promissory notes made by any
       Obligor for the benefit of such Pledgor or other securities, options or
       rights received by it in substitution or exchange for, or as a
       conversion of, or in addition to, any of the Pledged Notes, or otherwise
       in respect thereof, together with an undated endorsement or power, as
       the case may be, duly executed to the order of "Bearer" or in blank, as
       the case may be, by such Pledgor and with, if the Administrative Agent
       reasonably requests, signature guaranteed.

              6.     Cash Dividends; Voting Rights; Interest and Principal
Payments.  (a)  Unless an Event of Default shall have occurred and be
continuing and the Administrative Agent shall have given notice to a Pledgor of
the Administrative Agent's intent to exercise its corresponding rights pursuant
to Section 7 below, such Pledgor shall be permitted to receive all cash
dividends paid in the normal course of business and consistent with past
practice, to the extent permitted in the Credit Agreement, in respect of the
Pledged Stock of such Pledgor and to exercise all voting and corporate rights
with respect to such Pledged Stock; provided, however, that no vote shall be
cast or corporate right exercised or other action taken which, in the
Administrative Agent's reasonable judgment, would impair the Collateral or
which would be inconsistent with or result in any violation of any provision of
the Credit Agreement, the Notes, this Agreement or any other Loan Document.

              (b)    Unless an Event of Default shall have occurred and be
continuing and the Administrative Agent shall have given notice to a Pledgor of
the Administrative Agent's intent to exercise its corresponding rights pursuant
to Section 7 hereof, such Pledgor shall be permitted to receive and retain all
scheduled interest and principal payments on account of the Pledged Notes of
such Pledgor.
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                                                                               7



              7.     Rights of the Lenders and the Administrative Agent.  (a)
If an Event of Default shall occur and be continuing and the Administrative
Agent shall give notice of its intent to exercise such rights to a Pledgor, (1)
the Administrative Agent shall have the right to receive any and all cash
dividends paid in respect of the Pledged Stock of such Pledgor and any and all
interest, principal or other payments paid in respect of the Pledged Notes of
such Pledgor and make application thereof to the Obligations of such Pledgor in
such order as the Administrative Agent may determine, and (2) all shares of
such Pledged Stock shall be registered in the name of the Administrative Agent
or its nominee, and the Administrative Agent or its nominee may thereafter
exercise (A) all voting, corporate and other rights pertaining to such Pledged
Stock at any meeting of shareholders of any Issuer or otherwise and (B) any and
all rights of conversion, exchange, subscription and any other rights,
privileges or options pertaining to such Pledged Stock as if it were the
absolute owner thereof (including, without limitation, the right to exchange at
its discretion any and all of such Pledged Stock upon the merger,
consolidation, reorganization, recapitalization or other fundamental change in
the corporate structure of any Issuer, or upon the exercise by such Pledgor or
the Administrative Agent of any right, privilege or option pertaining to such
Pledged Stock, and in connection therewith, the right to deposit and deliver
any and all of such Pledged Stock with any committee, depositary, transfer
agent, registrar or other designated agency upon such terms and conditions as
the Administrative Agent may determine) and (3) the Administrative Agent or its
nominee may thereafter exercise all rights pertaining to such Pledged Notes
(including without limitation, any and all rights of conversion, exchange,
subscription and any other rights, privileges or options pertaining thereto) as
if it were the absolute owner thereof, all without liability except to account
for property actually received by it, but the Administrative Agent shall have
no duty to such Pledgor to exercise any such right, privilege or option and
shall not be responsible for any failure to do so or delay in so doing.

              (b)    Anything herein to the contrary notwithstanding, each
Pledgor shall remain liable under the Pledged Notes of such Pledgor to observe
and perform all the conditions and obligations to be observed and performed by
it thereunder all in accordance with the terms and provisions of such Pledged
Notes.  Neither the Administrative Agent nor the Lenders shall have any
obligation or liability under any Pledged Note by reason of or arising out of
this Agreement or the receipt by the Administrative Agent or the Lenders of any
payment relating to such Pledged Note pursuant hereto (other than to account
for monies actually received by it), nor shall the Administrative Agent or any
of the Lenders be obligated in any manner to perform any of the obligations of
any Pledgor under or pursuant to any Pledged Note, to make any payment, to make
any inquiry as to the nature or the sufficiency of any payment received by it
or as to the sufficiency of any performance by any party under any Pledged
Note, to present or file any claim, to take any action to enforce any
performance or to collect the payment of any amounts which may have been
assigned to it or to which it may be entitled at any time or times.

              (c)    The rights of the Administrative Agent and the Lenders
hereunder shall not be conditioned or contingent upon the pursuit by the
Administrative Agent or any Lender of any right or remedy against any Issuer or
any Obligor or against any other Person which may be or become liable in
respect of all or any part of the Obligations or against any collateral
security therefor, guarantee thereof or right of offset with respect thereto.
Neither the Administrative Agent
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nor any Lender shall be liable for any failure to demand, collect or realize
upon all or any part of the Collateral or for any delay in doing so, nor shall
the Administrative Agent be under any obligation to sell or otherwise dispose
of any Collateral upon the request of a Pledgor or any other Person or to take
any other action whatsoever with regard to the Collateral or any part thereof.

              8.     Remedies.  If an Event of Default shall occur and be
continuing, the Administrative Agent, on behalf of the Lenders, may exercise,
in addition to all other rights and remedies granted in this Agreement and in
any other instrument or agreement securing, evidencing or relating to the
Obligations, all rights and remedies of a secured party under the Code.
Without limiting the generality of the foregoing, the Administrative Agent,
without demand of performance or other demand, presentment, protest,
advertisement or notice of any kind (except any notice required by law referred
to below) to or upon any Pledgor, any Issuer, any Obligor or any other Person
(all and each of which demands, defenses, advertisements and notices are hereby
waived), may in such circumstances forthwith collect, receive, appropriate and
realize upon the Collateral, or any part thereof, and/or may forthwith sell,
assign, give option or options to purchase or otherwise dispose of and deliver
the Collateral or any part thereof (or contract to do any of the foregoing), in
one or more parcels at public or private sale or sales, in the over-the-counter
market, at any exchange, broker's board or office of the Administrative Agent
or any Lender or elsewhere upon such terms and conditions as it may deem
advisable and at such prices as it may deem best, for cash or on credit or for
future delivery without assumption of any credit risk.  The Administrative
Agent or any Lender shall have the right upon any such public sale or sales,
and, to the extent permitted by law, upon any such private sale or sales, to
purchase the whole or any part of the Collateral so sold, free of any right or
equity of redemption in any Pledgor, which right or equity is hereby waived or
released.  The Administrative Agent shall apply any Proceeds from time to time
held by it and the net proceeds of any such collection, recovery, receipt,
appropriation, realization or sale, after deducting all reasonable costs and
expenses of every kind incurred in respect thereof or incidental to the care or
safekeeping of any of the Collateral or in any way relating to the Collateral
or the rights of the Administrative Agent and the Lenders hereunder, including,
without limitation, reasonable attorneys' fees and disbursements of counsel to
the Administrative Agent, to the payment in whole or in part of the
Obligations, in such order as the Administrative Agent may elect, and only
after such application and after the payment by the Administrative Agent of any
other amount required by any provision of law, including, without limitation,
Section 9-504(1)(c) of the Code, need the Administrative Agent account for the
surplus, if any, to any Pledgor.  To the extent permitted by applicable law,
each Pledgor waives all claims, damages and demands it may acquire against the
Administrative Agent or any Lender arising out of the exercise by them of any
rights hereunder, except such claims and damages arising out of the gross
negligence or willful misconduct of the Administrative Agent or any such
Lender.  If any notice of a proposed sale or other disposition of Collateral
shall be required by law, such notice shall be deemed reasonable and proper if
given at least 10 days before such sale or other disposition.  Each Pledgor
shall remain liable for any deficiency if the proceeds of any sale or other
disposition of Collateral are insufficient to pay the Obligations of such
Pledgor and the fees and disbursements of any attorneys employed by the
Administrative Agent or any Lender to collect such deficiency.

              9.     Registration Rights; Private Sales.  (a)  If the
Administrative Agent shall determine to exercise its right to sell any or all
of the Pledged Stock of any Pledgor pursuant to
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paragraph 8 hereof, and if in the opinion of the Administrative Agent it is
necessary or advisable to have such Pledged Stock, or that portion thereof to
be sold, registered under the provisions of the Securities Act, such Pledgor
will cause the Issuer thereof to (1) execute and deliver, and cause the
directors and officers of such Issuer to execute and deliver, all such
instruments and documents, and do or cause to be done all such other acts as
may be, in the opinion of the Administrative Agent, necessary or advisable to
register such Pledged Stock, or that portion thereof to be sold, under the
provisions of the Securities Act, (2) to use its best efforts to cause the
registration statement relating thereto to become effective and to remain
effective for a period of one year from the date of the first public offering
of such Pledged Stock, or that portion thereof to be sold and (3) to make all
amendments thereto and/or to the related prospectus which, in the opinion of
the Administrative Agent, are necessary or advisable, all in conformity with
the requirements of the Securities Act and the rules and regulations of the
Securities and Exchange Commission applicable thereto.  Such Pledgor agrees  to
cause such Issuer to comply with the provisions of the securities or "Blue Sky"
laws of any and all jurisdictions which the Administrative Agent shall
designate and to make available to its security holders, as soon as
practicable, an earnings statement (which need not be audited) which will
satisfy the provisions of Section 11(a) of the Securities Act.

              (b)    Each Pledgor recognizes that the Administrative Agent may
be unable to effect a public sale of any or all the Pledged Stock, by reason of
certain prohibitions contained in the Securities Act and applicable state
securities laws or otherwise, and may be compelled to resort to one or more
private sales thereof to a restricted group of purchasers which will be obliged
to agree, among other things, to acquire such securities for their own account
for investment and not with a view to the distribution or resale thereof.  Such
Pledgor acknowledges and agrees that any such private sale may result in prices
and other terms less favorable than if such sale were a public sale and,
notwithstanding such circumstances, agrees that any such private sale shall be
deemed to have been made in a commercially reasonable manner.  The
Administrative Agent shall be under no obligation to delay a sale of any of the
Pledged Stock for the period of time necessary to permit the Issuer thereof to
register such securities for public sale under the Securities Act, or under
applicable state securities laws, even if such Issuer would agree to do so.

              (c)    Each Pledgor further agrees to use its best efforts to do
or cause to be done all such other acts as may be necessary to make such sale
or sales of all or any portion of the Pledged Stock pursuant to this Section
valid and binding and in compliance with any and all other applicable
Requirements of Law.  Such Pledgor further agrees that a breach of any of the
covenants contained in this Section will cause irreparable injury to the
Administrative Agent and the Lenders, that the Administrative Agent and the
Lenders have no adequate remedy at law in respect of such breach and, as a
consequence, that each and every covenant contained in this Section 9 shall be
specifically enforceable against such Pledgor, and such Pledgor hereby waives
and agrees not to assert any defenses against an action for specific
performance of such covenants except for a defense that no Event of Default has
occurred under the Credit Agreement.

              10.    Irrevocable Authorization and Instruction to Issuer and
Obligor.  Each Pledgor hereby authorizes and instructs each Issuer of its
Pledged Stock and each Obligor of its Pledged Notes to comply with any
instruction received by it from the Administrative Agent in writing that (a)
states that an Event of Default has occurred and (b) is otherwise in accordance
with
<PAGE>   10
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the terms of this Agreement, without any other or further instructions from
such Pledgor, and such Pledgor agrees that each such Issuer and each such
Obligor shall be fully protected in so complying.

              11.    Administrative Agent's Appointment as Attorney-in-Fact.
(a)  Each Pledgor hereby irrevocably constitutes and appoints the
Administrative Agent and any officer or agent of the Administrative Agent, with
full power of substitution, as its true and lawful attorney-in-fact with full
irrevocable power and authority in the place and stead of such Pledgor and in
the name of such Pledgor or in the Administrative Agent's own name, from time
to time in the Administrative Agent's discretion, for the purpose of carrying
out the terms of this Agreement, to take any and all appropriate action and to
execute any and all documents and instruments which may be necessary or
desirable to accomplish the purposes of this Agreement, including, without
limitation, any financing statements, endorsements, assignments or other
instruments of transfer.

              (b)    Each Pledgor hereby ratifies all that said attorneys shall
lawfully do or cause to be done pursuant to the power of attorney granted in
paragraph 11.(a).  All powers, authorizations and agencies contained in this
Agreement are coupled with an interest and are irrevocable until the
Obligations are paid in full and the Commitments are terminated.

              12.    Duty of Administrative Agent.  The Administrative Agent's
sole duty with respect to the custody, safekeeping and physical preservation of
the Collateral in its possession, under Section 9-207 of the Code or otherwise,
shall be to deal with it in the same manner as the Administrative Agent deals
with similar securities and property for its own account.  Neither the
Administrative Agent, any Lender nor any of their respective directors,
officers, employees or agents shall be liable for failure to demand, collect or
realize upon any of the Collateral or for any delay in doing so or shall be
under any obligation to sell or otherwise dispose of any Collateral upon the
request of any Pledgor or any other Person or to take any other action
whatsoever with regard to the Collateral or any part thereof.

              13.    Execution of Financing Statements.  Pursuant to Section 9-
402 of the Code, each Pledgor authorizes the Administrative Agent to file
financing statements with respect to the Collateral without the signature of
such Pledgor in such form and in such filing offices as the Administrative
Agent reasonably determines appropriate to perfect the security interests of
the Administrative Agent under this Agreement.

              14.    Authority of Administrative Agent.  Each Pledgor
acknowledges that the rights and responsibilities of the Administrative Agent
under this Agreement with respect to any action taken by the Administrative
Agent or the exercise or non-exercise by the Administrative Agent of any
option, voting right, request, judgment or other right or remedy provided for
herein or resulting or arising out of this Agreement shall, as between the
Administrative Agent and the Lenders, be governed by the Credit Agreement and
by such other agreements with respect thereto as may exist from time to time
among them, but, as between the Administrative Agent and a Pledgor, the
Administrative Agent shall be conclusively presumed to be acting as agent for
the Lenders with full and valid authority so to act or refrain from acting, and
neither any Pledgor, any Issuer nor any Obligor shall be under any obligation,
or entitlement, to make any inquiry respecting such authority.
<PAGE>   11
                                                                              11



              15.    Notices.  All notices, requests and demands to or upon the
Administrative Agent, any Pledgor, any Issuer or any Obligor to be effective
shall be in writing (or by telex, fax or similar electronic transfer confirmed
in writing) and shall be deemed to have been duly given or made (1) when
delivered by hand or (2) if given by mail, three days after being deposited in
the mail, postage prepaid, or (3) if by telex, fax or similar electronic
transfer, when sent and receipt has been confirmed, addressed to the
Administrative Agent at its address or transmission number for notices provided
in the Credit Agreement, to each Pledgor at its address or transmission number
for notices provided in the Subsidiaries Guarantee and to each Issuer and each
Obligor at its address set forth in its Acknowledgment and Consent.  Any
Pledgor, any Issuer and any Obligor may change their addresses and transmission
numbers for notices by written notice to the Administrative Agent.

              16.    Severability.  Any provision of this Agreement which is
prohibited or unenforceable in any jurisdiction shall, as to such jurisdiction,
be ineffective to the extent of such prohibition or unenforceability without
invalidating the remaining provisions hereof, and any such prohibition or
unenforceability in any jurisdiction shall not invalidate or render
unenforceable such provision in any other jurisdiction.

              17.    Amendments in Writing; No Waiver; Cumulative Remedies.
(a)  None of the terms or provisions of this Agreement as it affects any
Pledgor may be waived, amended, supplemented or otherwise modified except by a
written instrument executed by such Pledgor and the Administrative Agent,
provided that any provision of this Agreement may be waived by the
Administrative Agent and the Lenders in a letter or agreement executed by the
Administrative Agent or by telex or facsimile transmission from the
Administrative Agent.

              (b)    Neither the Administrative Agent nor any Lender shall by
any act (except by a written instrument pursuant to paragraph 17.(a) hereof),
delay, indulgence, omission or otherwise be deemed to have waived any right or
remedy hereunder or to have acquiesced in any Default or Event of Default or in
any breach of any of the terms and conditions hereof.  No failure to exercise,
nor any delay in exercising, on the part of the Administrative Agent or any
Lender, any right, power or privilege hereunder shall operate as a waiver
thereof.  No single or partial exercise of any right, power or privilege
hereunder shall preclude any other or further exercise thereof or the exercise
of any other right, power or privilege.  A waiver by the Administrative Agent
or any Lender of any right or remedy hereunder on any one occasion shall not be
construed as a bar to any right or remedy which the Administrative Agent or
such Lender would otherwise have on any future occasion.

              (c)    The rights and remedies herein provided are cumulative,
may be exercised singly or concurrently and are not exclusive of any other
rights or remedies provided by law.

              18.    Section Headings.  The Section headings used in this
Agreement are for convenience of reference only and are not to affect the
construction hereof or be taken into consideration in the interpretation
hereof.
<PAGE>   12
                                                                              12



              19.    Successors and Assigns.  This Agreement shall be binding
upon the successors and assigns of each Pledgor and shall inure to the benefit
of the Administrative Agent and the Lenders and their successors and assigns.

              20.    Governing Law.  This Agreement shall be governed by, and
construed and interpreted in accordance with, the law of the State of New York.
<PAGE>   13
                                                                              13



              IN WITNESS WHEREOF, the undersigned has caused this Agreement to
be duly executed and delivered as of the date first above written.



                                            ERIE SCIENTIFIC COMPANY
                                            NALGE NUNC INTERNATIONAL
                                                CORPORATION
                                            SYBRON DENTAL SPECIALTIES, INC.
                                            SAC/ORMCO, INC.
                                            ORMCO CORPORATION
                                            SAC/KERR, INC.
                                            KERR CORPORATION
                                            SAC/COMMONWEALTH, INC.
                                            SYBRON COMMONWEALTH HOLDINGS, INC.
                                            NUNC U.K. LIMITED
                                            SYBRON LABORATORY PRODUCTS
                                                CORPORATION
                                            NEW ENGLAND REAGENT LABORATORY,
                                                INC.
                                            REMEL INC.
                                            METREX RESEARCH CORPORATION
                                            LRS ACQUISITION CORP.
                                            "A" COMPANY ORTHODONTICS

                                            --------------------------------
                                            By:  John J. Buono, 
                                                 Assistant Treasurer
<PAGE>   14
                                                                      SCHEDULE 1
                                                             TO PLEDGE AGREEMENT



                          DESCRIPTION OF PLEDGED STOCK
                               [NAME OF PLEDGOR]


<TABLE>
<CAPTION>
                                                                                                             
                                                                       No. of Shares      Total No. of Shares
        Issuer           Class of Stock      Stock Certificate No.        Pledged             Outstanding    
<S>                      <C>                 <C>                       <C>                <C>
</TABLE>
<PAGE>   15
                                                                      SCHEDULE 2
                                                             TO PLEDGE AGREEMENT



                                 PLEDGED NOTES
                               [NAME OF PLEDGOR]


<TABLE>
<CAPTION>
                                                              Original
                                     Date of                  Principal
        Obligor                       Note                     Amount   
---------------------             ------------              ------------
<S>                               <C>                       <C>
                                                            $___________
</TABLE>
<PAGE>   16
                          ACKNOWLEDGEMENT AND CONSENT


              Each of the undersigned is an Issuer referred to in the foregoing
Pledge Agreement, and each of the undersigned hereby acknowledges receipt of a
copy of the Pledge Agreement, dated as of July 1, 1998, made by the Pledgors
(as defined therein) in favor of The Chase Manhattan Bank, as Administrative
Agent (as amended, supplemented or otherwise modified from time to time, the
"Pledge Agreement").  The undersigned agree for the benefit of the
Administrative Agent and the Lenders as follows:

              1.     The undersigned will be bound by the terms of the Pledge
Agreement and will comply with such terms insofar as such terms are applicable
to the undersigned.

              2.     The undersigned will notify the Administrative Agent
promptly in writing of the occurrence of any of the events described in
paragraph 5.(a) of the Pledge Agreement.

              3.  The terms of paragraph 9.(c) of the Pledge Agreement shall
apply to it, mutatis mutandis, with respect to all actions that may be required
of it under or pursuant to or arising out of Section 9 of the Pledge Agreement.


                                                  BARNSTEAD THERMOLYNE
                                                    CORPORATION
                                                  ERIE SCIENTIFIC COMPANY
                                                  ERIE ELECTROVERRE S.A.
                                                  ERIE SCIENTIFIC COMPANY OF
                                                    PUERTO RICO
                                                  ERIE-WATALA GLASS COMPANY
                                                    LIMITED
                                                  ERIE SCIENTIFIC HUNGARY KFT.
                                                  EVER READY THERMOMETER CO.,
                                                    INC.
                                                  RICHARD-ALLAN SCIENTIFIC
                                                    COMPANY
                                                  NEW ENGLAND REAGENT
                                                  LABORATORY, INC.
                                                  CASCO STANDARDS, INC.
                                                  THE NAUGATUCK GLASS COMPANY
                                                  NALGE NUNC INTERNATIONAL
                                                    CORPORATION
                                                  SAC/ORMCO, INC.
                                                  ORMCO CORPORATION
                                                  ORMCO (EUROPE) A.G.
                                                  ORMEX, S.A. DE C.V.
                                                  ORMCO PTY. LTD.
                                                  ORMCO DE MEXICO SA de CV
                                                  ALLESEE ORTHODONTIC
                                                    APPLIANCES, INC.
                                                  S.D.S. DE MEXICO, SA de CV
                                                  SAC/KERR, INC.
<PAGE>   17
                                                                              2


                                                    
                                     KERR CORPORATION
                                     KERR AUSTRALIA PTY. LIMITED
                                     KERR ITALIA S.P.A.
                                     KERR (EUROPE) A.G.
                                     METREX RESEARCH CORPORATION
                                     BELLE DE ST. CLAIRE, INC.
                                     SYBRON DEUTSCHLAND GMBH
                                     SAC/COMMONWEALTH, INC.
                                     SYBRON COMMONWEALTH HOLDINGS,
                                       INC.
                                     SYBRON CANADA LIMITED
                                     SYBRON U.K. LIMITED
                                     SYBRON HOLDINGS A/S
                                     REMEL INC.
                                     SYBRON DENTAL SPECIALTIES JAPAN,
                                       INC.
                                     DIAGNOSTIC REAGENTS, INC.
                                     NALGE PROCESS TECHNOLOGIES
                                       GROUP, INC.
                                     ALEXON-TREND, INC.
                                     CHASE SCIENTIFIC GLASS, INC.
                                     OWL SEPARATION SYSTEMS INC.
                                     CARR-SCARBOROUGH
                                       MICROBIOLOGICALS, INC.
                                     CLINICAL STANDARDS LABS, INC.
                                     VIRO RESEARCH INTERNATIONAL, INC.
                                     NALGE NUNC INTERNATIONAL K.K.
                                     LIDA MANUFACTURING CORPORATION
                                     SUMMIT BIOTECHNOLOGY, INC.
                                     SOCODENT S.A.
                                     SYBRON HOLDINGS A/S
                                     "A" COMPANY ORTHODONTICS
                                     MAQUILADORA ACI-MEX S.A. de C.V
                                     "A" COMPANY GmbH
                                     "A" ORTHONDONTICS B.V.
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                     ----------------
                                     By: John J. Buono, Assistant
                                     Secretary or Authorized Agent
                                                                                
                                                                                
                                                                                
                                                                                
                                                                                
                                     Address for Notices:
                                                                                
                                     c/o Sybron International Corporation
                                     411 East Wisconsin Avenue, 24th Floor
                                     Milwaukee, Wisconsin 53202
                                     Fax: (414) 274-6561