US3871876A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dental Amalgam
Assignee: ALLEGHENY INTERNATIONAL ACCEPTANCE Corp
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Filing: 1974-03-18
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Granted: 1975-03-18
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Expires: 1994-03-18
Abstract
Abstract An amalgamable silver-base metal powder containing about 8% to about 27% copper, 20% to about 32% tin, and the balance consisting essentially of silver, which upon admixture with about 42% to 54% mercury forms a dental amalgam of improved strength and corrosion resistance.
Inventors
- 👤 Kamal Asgar
- 👤 Steven H Reichman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:28
CPC Classifications
A; A61; A61K; A61K6/00; A61K6/80; A61K6/84; A61K6/847; C; C22; C22C; C22C7/00; Y; Y10; Y10S; Y10S75/00; Y10S75/955
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
90 words
AN AMALGAMABLE SILVER ALLOY POWDER IN WHICH EACH OF THE PARTICLES ARE OF SUBSTANTIALLY THE SAME COMPOSITION AND CONSIST ESSENTIALLY OF SILVER, TIN AND COPPER, SAID SILVER AND TIN BEING PRESENT AT RATIO OF FROM ABOUT 18:1 TO ABOUT 3.0:1 AND SAID TIN AND COPPER BEING PRESENT AT A RATIO OF ABOUT 1:1 UP TO 3:1 SAID POWDER FURTHER CHARACTERIZED AS BEING OF AN AVERAGE PARTICLE SIZE LESS THAN ABOUT 100 MICRONS AND WHEREIN EACH PARTICLE IS OF A GRADIENT COMPOSITION ON MOVING FROM THE SURFACE TOWARD THE CORE THEREOF.
Claim 2
Dependent Claim
90 words
AN AMALGAMABLE SILVER ALLOY POWDER IN WHICH EACH OF THE PARTICLES ARE OF SUBSTANTIALLY THE SAME COMPOSITION AND CONSIST ESSENTIALLY OF SILVER, TIN AND COPPER, SAID SILVER AND TIN BEING PRESENT AT RATIO OF FROM ABOUT 18:1 TO ABOUT 3.0:1 AND SAID TIN AND COPPER BEING PRESENT AT A RATIO OF ABOUT 1:1 UP TO 3:1 SAID POWDER FURTHER CHARACTERIZED AS BEING OF AN AVERAGE PARTICLE SIZE LESS THAN ABOUT 100 MICRONS AND WHEREIN EACH PARTICLE IS OF A GRADIENT COMPOSITION ON MOVING FROM THE SURFACE TOWARD THE CORE THEREOF.
Claim 3
Dependent Claim
23 words
The amalgamable silver alloy powder as defined in claim 1 in which said ratio of silver-to-tin ranges from about 2.2 to about 2.6.
Claim 4
Dependent Claim
23 words
The amalgamable silver alloy powder as defined in claim 1 in which said ratio of tin-to-copper ranges from about 1.5 to about 2.5.
Claim 5
Dependent Claim
26 words
The amalgamable silver alloy powder as defined in claim 1 in which the average particle size thereof ranges from about 45 microns to about 5 microns.
Claim 6
Dependent Claim
123 words
A DENTAL AMALGAM CONSISTING ESSENTIALLY OF A CONTINUOUS MATRIX COMPOSED OF AN AMALGAM HAVING INTERSPERSED THERETHROUGH A PLURALITY OF DISCRETE PHASES CHEMICALLY BONDED BY SAID CONTINUOUS PHASE INTO AN INTEGRAL MATRIX, SAID DISCRETE PHASE COMPRISING PARTICLES OF AN ALLOY CONSISTING ESSENTIALLY OF SILVER, TIN AND COPPER AND WHEREIN THE PARTICLES ARE OF A GRADIENT COMPOSITION ON MOVING FROM THE SURFACES THEREOF TOWARD THEIR CENTER, SAID ONTINUOUS PHASE COMPRISING INTERMETALLIC COMPOUNDS OF MERCURY WITH SILVER, TIN AND COPPER, SAID DENTAL AMALGAM CONTAINING FROM ABOUT 42% TO ABOUT 54% MERCURY, AND SAID SILVER, TIN SAID COPPER BEING PRESENT IN AMOUNTS SO AS TO PROVIDE A RATIO OF SILVER-TO-TIN OF FROM ABOUT 1.8 UP TO ABOUT 3.0 AND TIN-TO-COPPER OF FROM ABOUT 1:1 UP TO 3:1.
Claim 7
Dependent Claim
123 words
A DENTAL AMALGAM CONSISTING ESSENTIALLY OF A CONTINUOUS MATRIX COMPOSED OF AN AMALGAM HAVING INTERSPERSED THERETHROUGH A PLURALITY OF DISCRETE PHASES CHEMICALLY BONDED BY SAID CONTINUOUS PHASE INTO AN INTEGRAL MATRIX, SAID DISCRETE PHASE COMPRISING PARTICLES OF AN ALLOY CONSISTING ESSENTIALLY OF SILVER, TIN AND COPPER AND WHEREIN THE PARTICLES ARE OF A GRADIENT COMPOSITION ON MOVING FROM THE SURFACES THEREOF TOWARD THEIR CENTER, SAID ONTINUOUS PHASE COMPRISING INTERMETALLIC COMPOUNDS OF MERCURY WITH SILVER, TIN AND COPPER, SAID DENTAL AMALGAM CONTAINING FROM ABOUT 42% TO ABOUT 54% MERCURY, AND SAID SILVER, TIN SAID COPPER BEING PRESENT IN AMOUNTS SO AS TO PROVIDE A RATIO OF SILVER-TO-TIN OF FROM ABOUT 1.8 UP TO ABOUT 3.0 AND TIN-TO-COPPER OF FROM ABOUT 1:1 UP TO 3:1.
Claim 8
Dependent Claim
20 words
The dental amalgam as defined in claim 5, wherein the concentration of mercury ranges from about 46% to about 50%.
Claim 9
Dependent Claim
33 words
The dental amalgam as defined in claim 5 in which said ratio of silver-to-tin ranges from about 2.2 to about 2.6 while the ratio of tin-to-copper ranges from about 1.5 to about 2.5.
Claim 10
Dependent Claim
16 words
The amalgamable silver alloy powder as defined in claim 1, further including up to 2% zinc.
Claim 11
Dependent Claim
15 words
The dental amalgam as defined in claim 5, further including up to about 2% zinc.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-17 | 1978-09-16 | 1979-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-17 | 1982-09-16 | 1983-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-17 | 1986-09-16 | 1987-03-18 | $7700.00 | Window Closed / Lapsed |