Patent US3980472A successfully refreshed from Google Patents.
US3980472A
Expired / Lapsed
US
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Dental amalgam
Assignee: ALLEGHENY INTERNATIONAL ACCEPTANCE Corp
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Filing: 1975-07-16
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Granted: 1976-09-14
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Expires: 1995-07-16
Abstract
Abstract An improved metal powder blend and improved dental amalgams produced therefrom comprising a mechanical mixture containing controlled proportions of an amalgamatable silver-base alloy powder and a substantially non-amalgamatable eutectic alloy powder containing a controlled quantity of tin which upon trituration with mercury forms a substantially continuous matrix having dispersed therethrough discrete phases of the non-amalgamatable powder particles which impart improved mechanical properties to the resultant dental restoration.
Inventors
- 👤 Kamal Asgar
- 👤 Steven H. Reichman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:50
CPC Classifications
C; C22; C22C; C22C5/00; C22C5/06; A; A61; A61K; A61K6/00; A61K6/80; A61K6/84; A61K6/847; Y; Y10; Y10S; Y10S75/00; Y10S75/955
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
178 words
A metal powder for use in the preparation of dental restorations and the like by trituration with mercury comprising a mechanical mixture containing about 55% to about 90% of a first powder comprised of a silver-base amalgamatable alloy and about 10% to about 45% of a second powder composed of a substantially non-amalgamatable silver-containing alloy, said first powder consisting essentially of at least about 65% silver, up to about 6% copper, up to about 2% zinc and at least about 25% tin, said second powder consisting essentially of about 1% to about 20% tin, silver as the major alloying agent, and a third alloying constituent individually selected from the group consisting of 5% to 50% cadmium, 5% to 50% zinc, 5% to 50% aluminum, copper in an amount to provide a silver-to-copper ratio of about 2.6:1, up to 30% indium in combination with copper wherein the latter is present in an amount to provide a silver-to-copper ratio of about 2.6:1; said first and said second powder being of an average particle size of less than about 100 microns.
Claim 2
Dependent Claim
178 words
A metal powder for use in the preparation of dental restorations and the like by trituration with mercury comprising a mechanical mixture containing about 55% to about 90% of a first powder comprised of a silver-base amalgamatable alloy and about 10% to about 45% of a second powder composed of a substantially non-amalgamatable silver-containing alloy, said first powder consisting essentially of at least about 65% silver, up to about 6% copper, up to about 2% zinc and at least about 25% tin, said second powder consisting essentially of about 1% to about 20% tin, silver as the major alloying agent, and a third alloying constituent individually selected from the group consisting of 5% to 50% cadmium, 5% to 50% zinc, 5% to 50% aluminum, copper in an amount to provide a silver-to-copper ratio of about 2.6:1, up to 30% indium in combination with copper wherein the latter is present in an amount to provide a silver-to-copper ratio of about 2.6:1; said first and said second powder being of an average particle size of less than about 100 microns.
Claim 3
Dependent Claim
29 words
The metal powder as defined in claim 1, in which said mechanical mixture contains 65% to 75% of said first powder and 25% to 35% of said second powder.
Claim 4
Dependent Claim
31 words
The metal powder as defined in claim 1, in which said first and said second powders are of an average particle size ranging from about 5 microns to about 45 microns.
Claim 5
Dependent Claim
23 words
The metal powder as defined in claim 1, wherein the tin content of said second powder ranges from about 2% to about 10%.
Claim 6
Dependent Claim
33 words
The metal powder as defined in claim 1, wherein said second powder consists essentially of a eutectic silver-copper alloy having a silver-to-copper ratio of about 2.6:1 containing from 2% up to 20% tin.
Claim 7
Dependent Claim
23 words
The metal powder as defined in claim 5, wherein the tin content of said second powder ranges from about 2% to about 10%.
Claim 8
Dependent Claim
169 words
A dental amalgam consisting essentially of a continuous matrix composed of an amalgam having dispersed therethrough a plurality of discrete phases chemically bonded by said continuous matrix, said amalgam containing from about 40% to about 60% mercury, from about 22% to about 54% of an amalgamatable alloy powder containing at least about 65% silver, up to about 6% copper, up to about 2% zinc, and greater than about 25% tin; said discrete phases comprising about 4% to about 27% of said amalgam consisting essentially of an alloy containing silver, from about 1% to about 20% tin, and the balance an alloying constituent individually selected from the group consisting of 5% to 50% cadmium, 5% to 50% zinc, 5% to 50% aluminum, copper in an amount to provide a silver-to-copper ratio of about 2.6:1, up to 30% indium in combination with copper wherein the latter is present in an amount to provide a silver-to-copper ratio of about 2.6:1; said discrete phases being of a size less than about 100 microns.
Claim 9
Dependent Claim
169 words
A dental amalgam consisting essentially of a continuous matrix composed of an amalgam having dispersed therethrough a plurality of discrete phases chemically bonded by said continuous matrix, said amalgam containing from about 40% to about 60% mercury, from about 22% to about 54% of an amalgamatable alloy powder containing at least about 65% silver, up to about 6% copper, up to about 2% zinc, and greater than about 25% tin; said discrete phases comprising about 4% to about 27% of said amalgam consisting essentially of an alloy containing silver, from about 1% to about 20% tin, and the balance an alloying constituent individually selected from the group consisting of 5% to 50% cadmium, 5% to 50% zinc, 5% to 50% aluminum, copper in an amount to provide a silver-to-copper ratio of about 2.6:1, up to 30% indium in combination with copper wherein the latter is present in an amount to provide a silver-to-copper ratio of about 2.6:1; said discrete phases being of a size less than about 100 microns.
References Cited (Backward Citations)
US3305356A
Cited
US3841860A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-09-14 | 1980-03-15 | 1980-09-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-14 | 1984-03-15 | 1984-09-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-14 | 1988-03-15 | 1988-09-14 | $7700.00 | Window Closed / Lapsed |