Ex parte OXMAN

Board of Patent Appeals and Interferences

May 20, 1998

08014104 (B.P.A.I. May. 20, 1998)

Application for patent filed February 5, 1993.1
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THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered
today (1) was not written for publication in a law
journal and (2) is not binding precedent of the Board.
Paper No. 25
UNITED STATES PATENT AND TRADEMARK OFFICE
________________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte JOEL D. OXMAN
________________
Appeal No. 95-0992
Application 08/014,1041
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HEARD: MAY 5, 1998
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Before GARRIS, WARREN and OWENS, Administrative Patent Judges.
OWENS, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal from the examiner’s final rejection of
claims 1-4, 7, 9, 14, 15, 17, 21, 22 and 31, and refusal to allow
claims 16 and 18 as amended after final rejection. Claims 33-38
have been indicated allowable, and claims 5, 6, 8, 10-13, 19, 20,
23-30 and 32 stand objected to as being dependent from a rejected
Appeal No. 95-0992
Application 08/014,104
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claim.
THE INVENTION
Appellant claims a method and kit for obtaining high bond
strength to a previously set dental amalgam (specification, page
3, lines 27-28). The method includes applying to the amalgam a
primer and an adhesive, where the primer includes an oxidant
which has an oxidation-reduction half-reaction electrode
potential which is greater than the absolute value of that of the
amalgam. The kit includes a primer which contains an oxidant
having an oxidation-reduction half-reaction electrode potential
greater than 0.8 volts. Claims 1 and 21 are illustrative and
read as follows:
1. A method for adhering to or coating a dental metal,
comprising the steps of:
applying to said dental metal adhesively effective amounts
of a primer composition and an adhesive, wherein said primer
composition comprises an exodant having an EE oxidation potential
greater than the absolute value of the EE reductant of said
dental metal; and
hardening said adhesive.
21. A kit for adhering to or coating dental amalgam,
comprising:
a primer comprising an oxidant having an EE oxidation
potential greater than 0.8 Volts; and an adhesive, wherein upon
hardening said adhesive is capable of providing an average
measured shear strength of at least 7 MPa between said adhesive
and dental amalgam.
Appeal No. 95-0992
Application 08/014,104
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THE REFERENCES
Reference relied upon by the examiner
Stoner et al. (Stoner) 4,064,629 Dec. 27, 1977
References relied upon by appellant
The Chemist’s Ready Reference Handbook 16.1-16.4 (Gershon J.
Shugar et al. eds., McGraw-Hill 1990) (Chemist’s Handbook).
CRC Handbook of Chemistry and Physics D-157 - D-159 (Robert C.
Weast ed., CRC Press 1980) (CRC Handbook).
THE REJECTION
Claims 1-4, 7, 9, 14-18, 21, 22 and 31 stand rejected under
35 U.S.C. § 103 as being unpatentable over Stoner.
OPINION
We have carefully considered all of the arguments advanced
by appellant and the examiner and agree with appellant that the
aforementioned rejection is not well founded. Accordingly, this
rejection will be reversed.
Stoner discloses that when the surfaces of a dental cavity
are coated with a metallic film of a metal more positive than tin
in the International Electromotive Series such as silver, gold,
platinum, indium, copper, alloys thereof or alloys with a metal
inert to the system, and then the lined cavity is filled with
dental amalgam, the restoration produced is extremely resistant
to corrosion and has a long lifetime compared to conventional
Appeal No. 95-0992
Application 08/014,104
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restorations (col. 3, lines 50-61). Stoner states that he
believes that the improved corrosion results from mercury from
the bulk of the amalgam diffusing into the metal of the lining
and forming an alloy zone free of tin atoms next to the cavity
surfaces (col. 3, lines 61-64). Since no tin atoms are present
next to the cavity surfaces, Stoner states, there is no oxidation
in this region (col. 3, lines 64-66).
Appellant’s specification (page 5, lines 1-2) states that
the primary components of dental amalgams include metallic
mercury, silver and tin. The following table shows the
potentials for oxidation-reduction half-reactions at 25EC for
these elements taken from the CRC Handbook, pages D-158 to D-159.
Following these potentials in the table are the potentials for
platinum and gold, which are two of the elements disclosed by
Stoner. The oxidation strengths increase in the downward
direction in the table, as EE increases.
EE
(volts)
Sn + 2e = Sn -0.1364+2 -
Ag + e = Ag .7996+ -
Hg + 2e = Hg .851+2 -
Pt + 2e = Pt -1.2+2 -
Au + e = Au 1.68+ -
The first three entries in the table indicate that an
Appeal No. 95-0992
Application 08/014,104
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amalgam made of a mixture of tin, silver and mercury would have
an EE no greater than 0.851. The examiner’s position is that
since platinum and gold have electrode potentials of -1.2 and
1.68 volts, respectively, which are greater than the absolute
value of the EE of such an amalgam as recited in appellant’s
claim 1 and are greater than 0.8 volts as recited in appellant’s
claim 21, a primer which includes either of these metals would
fall within the scope of appellant’s claims (answer, page 6).
As explained on page 16.3 of the Chemist’s Handbook, since
the oxidation strengths of Pt and Au are greater than those of+2 +
Sn , Ag and Hg , Pt and Au may oxidize the amalgam elemental+2 + +2 +2 +
metals. Stoner does not disclose use of Pt and Au but, rather,+2 +
discloses use of elemental Pt and Au (col. 3, line 55). Platinum
can exist only in the 0, +2 and +4 valence states, and gold can
exist only in the 0, +1 and +3 valence states. The examiner has
not explained, and it is not apparent, how Pt or Au in the
elemental (i.e., 0 valence) state can serve as an oxidant and
thereby be reduced to a lower valence state. The oxidation-
reduction half-reaction potentials relied upon by the examiner
indicate that Pt and Au may serve as an oxidant, but do not+2 +
indicate that Stoner’s elemental platinum or gold may do so.
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For the above reasons, we conclude that the examiner has not
carried his burden of establishing a prima facie case of
obviousness of appellant’s claimed invention.
DECISION
The rejection of claims 1-4, 7, 9, 14-18, 21, 22 and 31
stand rejected under 35 U.S.C. § 103 over Stoner is reversed.
REVERSED
BRADLEY R. GARRIS )
Administrative Patent Judge )
)
)
)
CHARLES F. WARREN ) BOARD OF PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
)
)
TERRY J. OWENS )
Administrative Patent Judge )
Appeal No. 95-0992
Application 08/014,104
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F. Andrew Ubel
3M Office of Intellectual Property Counsel
P.O. Box 33427
St. Paul, MN 55133-3427