Patent US3997328A successfully refreshed from Google Patents.
US3997328A
Expired / Lapsed
US
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Dental amalgams
Assignee: Engelhard Minerals and Chemicals Corp
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Filing: 1975-12-29
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Granted: 1976-12-14
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Expires: 1995-12-29
Abstract
Abstract Dental compositions comprising an admixture of two powdered alloys which when amalgamated with mercury produce corrosion-resistant dental amalgams.
Inventors
- 👤 Evan H. Greener
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 13:32
CPC Classifications
C; C22; C22C; C22C5/00; C22C5/06; A; A61; A61K; A61K6/00; A61K6/80; A61K6/84; A61K6/847
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
95 words
A composition adapted for amalgamation with mercury to form a dental amalgam consisting essentially of a uniform admixture of a major proportion of a first alloy composed of about 40 to 70% by weight silver, about 10 to 30% by weight tin and about 20 to 40% by weight copper in particulate form, and a minor proportion of a second alloy composed of about 55 to 75% by weight silver, about 20 to 40% by weight tin, about 0.05 to 10% by weight copper and about 0.1 to 2.0% by weight zinc in particulate form.
Claim 2
Dependent Claim
95 words
A composition adapted for amalgamation with mercury to form a dental amalgam consisting essentially of a uniform admixture of a major proportion of a first alloy composed of about 40 to 70% by weight silver, about 10 to 30% by weight tin and about 20 to 40% by weight copper in particulate form, and a minor proportion of a second alloy composed of about 55 to 75% by weight silver, about 20 to 40% by weight tin, about 0.05 to 10% by weight copper and about 0.1 to 2.0% by weight zinc in particulate form.
Claim 3
Dependent Claim
18 words
A composition of claim 1 wherein both of the alloys are in the form of irregularly shaped particles.
Claim 4
Dependent Claim
25 words
The composition of claim 1 wherein both of the alloys have a particle size distribution in the range of about 1 to about 100 microns.
Claim 5
Dependent Claim
29 words
The composition of claim 1 containing about 55 to about 90% by weight of said first alloy and about 10 to about 45% by weight of said second alloy.
Claim 6
Dependent Claim
26 words
The composition of claim 1 wherein approximately 3 parts by weight of said first alloy are employed per 1 part by weight of said second alloy.
Claim 7
Dependent Claim
24 words
A process for preparing a dental amalgam which comprises triturating the composition of claim 1 with sufficient mercury to form a workable plastic amalgam.
Claim 8
Dependent Claim
132 words
A composition adapted for amalgamation with mercury to form a dental amalgam comprising a substantially uniform blend of: a. about 55 to 95% by weight of a first powder having a particle size distribution in the range of about 1 to 100 microns and consisting essentially of an alloy of about 40 to 70% by weight silver, about 10 to 30% by weight tin and about 20 to 40% by weight copper; and b. about 5 to 45% by weight of a second powder having a particle size distribution in the range of about 1 to 100 microns and consisting essentially of an alloy of about 55 to 75% by weight silver, about 20 to 40% tin, about 0.05 to 10% by weight copper and about 0.1 to 2.0% by weight zinc.
Claim 9
Dependent Claim
132 words
A composition adapted for amalgamation with mercury to form a dental amalgam comprising a substantially uniform blend of: a. about 55 to 95% by weight of a first powder having a particle size distribution in the range of about 1 to 100 microns and consisting essentially of an alloy of about 40 to 70% by weight silver, about 10 to 30% by weight tin and about 20 to 40% by weight copper; and b. about 5 to 45% by weight of a second powder having a particle size distribution in the range of about 1 to 100 microns and consisting essentially of an alloy of about 55 to 75% by weight silver, about 20 to 40% tin, about 0.05 to 10% by weight copper and about 0.1 to 2.0% by weight zinc.
Claim 10
Dependent Claim
44 words
A process for preparing a dental amalgam which comprises triturating the composition of claim 7 with mercury in the proportion of about 0.8 to about 1.5 parts by weight of mercury per part by weight of said composition to form a workable plastic amalgam.
References Cited (Backward Citations)
US1963085A
Cited
US2281991A
Cited
US3305356A
Cited
US3841860A
Cited
US3871876A
Cited
US3933961A
Cited
US3954457A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-12-14 | 1980-06-14 | 1980-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-12-14 | 1984-06-14 | 1984-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-12-14 | 1988-06-14 | 1988-12-14 | $7700.00 | Window Closed / Lapsed |