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                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                                  -----------
                                   SCHEDULE TO
                                 AMENDMENT NO. 4

           TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) or 13(e)(1)
                     OF THE SECURITIES EXCHANGE ACT OF 1934

                         SYBRON DENTAL SPECIALTIES, INC.
                            (Name of Subject Company)

                               DANAHER CORPORATION
                             SMILE ACQUISITION CORP.
                       (Name of Filing Persons--Offerors)

                    COMMON STOCK, PAR VALUE $0.01 PER SHARE
          (INCLUDING THE ASSOCIATED PREFERRED STOCK PURCHASE RIGHTS)
                         (Title of Class of Securities)

                                    871142105
                      (CUSIP Number of Class of Securities)

                                 Daniel L. Comas
             Executive Vice President and Chief Financial Officer
                               Danaher Corporation
                          2099 Pennsylvania Avenue, NW
                                   12th Floor
                             Washington, D.C. 20006
                                 (202) 828-0850
           (Name, Address and Telephone Number of Person Authorized
      to Receive Notices and Communications on Behalf of Filing Persons)

                                   -Copies to-
                             Trevor S. Norwitz, Esq.
                         Wachtell, Lipton, Rosen & Katz
                               51 West 52nd Street
                               New York, NY 10019
                                 (212) 403-1000
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                            CALCULATION OF FILING FEE

              Transaction Valuation          Amount of Filing Fee
              ---------------------------------------------------
                   2,046,908,434*                  $219,019*
              ---------------------------------------------------

              ---------------------------------------------------
*   Estimated for purposes of calculating the amount of the filing fee only. The
    calculation of the filing fee is described on the cover page to the Schedule
    TO filed on April 18, 2006.
[X] Check  the  box if any  part  of the  fee is  offset  as  provided  by  Rule
    0-11(a)(2)  and  identify the  filing  with  which  the  offsetting  fee was
    previously  paid.  Identify the  previous  filing by  registration statement
    number, or the Form or Schedule and the date of its filing.
      Amount Previously Paid:  $219,019       Filing Party:  Danaher Corporation
      Form or Registration No.:  Schedule TO  Date Filed:  April 18, 2006
[_] Check the box if the filing  relates  solely to  preliminary  communications
    made before the commencement of a tender offer.
Check the  appropriate  boxes below to designate any  transactions  to which the
   statement relates:
[X] third-party tender offer subject to Rule 14d-1.
[_] issuer tender offer subject to Rule 13e-4.
[_] going-private transaction subject to Rule 13e-3.
[_] amendment to Schedule 13D under Rule 13d-2.
Check the following box if the filing is a final amendment reporting the results
of the tender offer: [_]
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           This  Amendment  No.  4  amends  and  supplements  the  Tender  Offer
Statement on Schedule TO, as amended, (the "SCHEDULE TO"), originally filed with
the  Securities  and  Exchange  Commission  on April 18, 2006 and as amended and
supplemented by Amendment No. 1 on April 21, 2006,  Amendment No. 2 on April 26,
2006 and Amendment No. 3 on May 3, 2006, by Danaher Corporation  ("DANAHER"),  a
Delaware  corporation,  and Smile  Acquisition Corp.  ("PURCHASER"),  a Delaware
corporation and an indirect wholly owned subsidiary of Danaher.  The Schedule TO
relates to the offer by  Purchaser  to purchase  any and all of the  outstanding
shares of common  stock,  par value  $0.01 per share (the  "SHARES"),  of Sybron
Dental  Specialties,  Inc., a Delaware  corporation  ("SYBRON"),  for $47.00 per
Share,  net to the seller in cash,  upon the terms and subject to the conditions
set  forth in the  Offer to  Purchase,  dated  April  18,  2006  (the  "OFFER TO
PURCHASE"),  and in the related  Letter of  Transmittal.  Copies of the Offer to
Purchase and the related Letter of Transmittal are filed with the Schedule TO as
exhibits (a)(1)(A) and (a)(1)(B),  respectively.  Capitalized terms used and not
defined  herein  shall  have the  meanings  assigned  such terms in the Offer to
Purchase and Schedule TO.

           The Schedule  TO, which  incorporates  by reference  the  information
contained  in the Offer to  Purchase,  is hereby  amended  and  supplemented  as
follows:

           On May 5, 2006, an agreement in principle  was reached to settle a
class action law suit filed on April  24,  2006 by  Dolphin  Limited Partnership
I,  L.P.  and other parties,  in the Superior Court of the State of California,
Orange County.  The settlement  resolves  allegations by the plaintiffs against
Danaher,  Sybron and Sybron's  directors,  in  connection with the tender offer,
and  includes  no admission of  wrongdoing.  Under the terms of the  settlement,
the parties have agreed to reduce  the  termination fees  associated  with the
transaction.  In addition,  the parties have agreed that  Sybron's  shareholders
rights plan and other contractual  restrictions will not be applicable to tender
offers offering Sybron's  shareholders  above $47 in cash by third  parties who
sign and deliver the same merger  agreement that Danaher has signed and comply
with certain other conditions.  A copy of the Memorandum of Understanding  is
filed as  Exhibit  (a)(6)(B) hereto and is incorporated herein by reference.

           On May 5, 2006,  Danaher and Sybron issued a press release announcing
the  settlement,  a copy of which is filed as  Exhibit  (a)(5)(E)  hereto and is
incorporated herein by reference.

ITEM 12.  EXHIBITS

           Item 12 of the  Schedule TO is hereby  amended by adding  thereto the
following:

      (a)(5)(E)  Text of press release issued by Danaher and Sybron dated May 5,
                 2006.

      (a)(6)(B)  Memorandum of Understanding dated May 5, 2006.



                                    SIGNATURE

      After due inquiry and to the best of my  knowledge  and belief,  I certify
that the information set forth in this statement is true, complete and correct.

Dated:  May 5, 2006

                                    DANAHER CORPORATION


                                    By: /S/ DANIEL L. COMAS
                                        --------------------------
                                        Name:   Daniel L. Comas
                                        Title:  Executive Vice President and
                                                      Chief Financial Officer


                                    SMILE ACQUISITION CORP.


                                    By: /S/ DANIEL L. COMAS
                                        --------------------------
                                        Name:   Daniel L. Comas
                                        Title:  President



                                  EXHIBIT INDEX



*(a)(1)(A)     Offer to Purchase, dated April 18, 2006.

*(a)(1)(B)     Form of Letter of Transmittal.

*(a)(1)(C)     Form of Notice of Guaranteed Delivery.

*(a)(1)(D)     Form of Letter to Brokers, Dealers, Commercial Banks, Trust
               Companies and Other Nominees.

*(a)(1)(E)     Form of Letter to Clients for use by Brokers, Dealers, Commercial
               Banks, Trust Companies and Other Nominees.

*(a)(1)(F)     Guidelines for Certification of Taxpayer Identification Number on
               Substitute Form W-9.

(a)(2)         Not applicable.

(a)(3)         Not applicable.

(a)(4)         Not applicable.

*(a)(5)(A)     Text of press release issued by Danaher dated April 12, 2006.

*(a)(5)(B)     Form of summary advertisement dated April 18, 2006.

*(a)(5)(C)     Excerpt from transcript of Danaher's first quarter 2006 earnings
               call, dated April 20, 2006.

*(a)(5)(D)     Text of press release issued by Danaher dated May 3, 2006.

(a)(5)(E)      Text of press release issued by Danaher and Sybron dated May 5,
               2006.

*(a)(6)(A)     Complaint titled Dolphin Limited Partnership I, L.P. et al. v.
               Sybron Dental Specialties, Inc. et al., filed on April 24, 2006,
               in the Superior Court of the State of California, County of
               Orange, Case No. 06CC00082.

(a)(6)(B)      Memorandum of Understanding, dated May 5, 2006.

*(b)(1)        Credit Agreement, dated as of April 25, 2006, among Danaher
               Corporation and Bank of America, N.A., et al.

*(b)(2)        Commitment letter with respect to a US$700,000,000 364 Day
               Revolving Credit Facility for Danaher Corporation, dated April
               11, 2006, by UBS Loan Finance LLC.

*(d)(1)        Agreement and Plan of Merger, dated as of April 12, 2006, between
               Danaher, the Purchaser and Sybron.

*(d)(2)        Confidentiality Agreement, dated as of March 13, 2006, between
               Danaher and Sybron.




(g)            None.

(h)            Not applicable.


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* Previously filed.