Patent US4235631A successfully refreshed from Google Patents.
US4235631A
Expired / Lapsed
US
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Corrosion-resistant dental alloy having improved handling characteristics
Assignee: BASF Catalysts LLC
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Filing: 1978-08-24
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Granted: 1980-11-25
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Expires: 1998-08-24
Abstract
Abstract A corrosion-resistant dental alloy shows improved handling characteristics during the filling of a dental cavity with an amalgam of the alloy. The alloy particles comprise a mixture of silver, tin and copper particles having a mean particle size of between about 20 and 26.5 microns, and further having a particle size distribution such that substantially all of the particles fall within a particle size range of from about 10 to 52 microns. The particles have a surface area ranging between about 0.22 m2/gm and 0.31 m2/gm. The alloy, after amalgamation with mercury, retains a corrosion resistance comparable to that of spherical particles having substantially the same composition and having a surface area of about 0.21 m2/gm, while retaining handling characteristics comparable to those of flake-like particles also having substantially the same composition and having a surface area of at least about 0.33 m2/gm. The copper and silver content of the particles may be higher at their surface than in the interior thereof.
Inventors
- 👤 Joseph Aliotta
- 👤 Louis F. Alcuri, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:31
CPC Classifications
A; A61; A61K; A61K6/00; A61K6/80; A61K6/84; A61K6/847; B; B22; B22F; B22F1/00; B22F1/09
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
188 words
A corrosion-resistant dental alloy in particulate form for use as a filling for dental cavities after amalgamation with mercury, comprising a mixture of silver, tin and copper, said alloy consisting essentially of randomly shaped particles having a mean particle size of between about 20 and 26.5 microns, and further having a particle size distribution such that substantially all of said particles fall within a particle size range of from about 1 to 75 microns, said particles having a surface area which, exclusive of both spherical particles and flake-like particles as defined below, ranges from 0.22 m 2 /gm to about 0.31 m 2 /gm, so that said alloy, after amalgamation, retains a corrosion resistance comparable to that of spherical particles having substantially the same composition and having a surface area of about 0.21 m 2 /gm, but in any event, less than 0.22 m 2 /gm, while retaining handling characteristics comparable to those of flake-like particles also having substantially the same composition and having a surface area of at least about 0.33 m 2 /gm and approximately the same particle size and distribution as said randomly shaped particles.
Claim 2
Dependent Claim
188 words
A corrosion-resistant dental alloy in particulate form for use as a filling for dental cavities after amalgamation with mercury, comprising a mixture of silver, tin and copper, said alloy consisting essentially of randomly shaped particles having a mean particle size of between about 20 and 26.5 microns, and further having a particle size distribution such that substantially all of said particles fall within a particle size range of from about 1 to 75 microns, said particles having a surface area which, exclusive of both spherical particles and flake-like particles as defined below, ranges from 0.22 m 2 /gm to about 0.31 m 2 /gm, so that said alloy, after amalgamation, retains a corrosion resistance comparable to that of spherical particles having substantially the same composition and having a surface area of about 0.21 m 2 /gm, but in any event, less than 0.22 m 2 /gm, while retaining handling characteristics comparable to those of flake-like particles also having substantially the same composition and having a surface area of at least about 0.33 m 2 /gm and approximately the same particle size and distribution as said randomly shaped particles.
Claim 3
Dependent Claim
26 words
The corrosion-resistant dental alloy of claim 1 wherein said particles have a surface area ranging between about 0.23 m 2 /gm and 0.26 m 2 /gm.
Claim 4
Dependent Claim
16 words
The corrosion-resistant dental alloy of claim 1 in combination with mercury to provide a dental amalgam.
Claim 5
Dependent Claim
27 words
The corrosion-resistant dental alloy of claim 1 in combination with about 1 part by weight of mercury for each part by weight of said corrosion-resistant dental alloy.
Claim 6
Dependent Claim
47 words
The corrosion-resistant dental alloy of claim 1 wherein said mixture of silver, tin and copper comprises from about 47 to 70 percent by weight of silver, from about 20 to 32 percent by weight of tin, and from about 7 to 27 percent by weight of copper.
Claim 7
Dependent Claim
30 words
The corrosion-resistant dental alloy of claim 1 wherein at least about 90% by weight of said particles fall within a particle size range of from about 10 to 52 microns.
Claim 8
Dependent Claim
155 words
A corrosion-resistant dental alloy in particulate form for use as a filling for dental cavities after amalgamation with mercury comprising a mixture of silver, tin and copper, said alloy consisting essentially of randomly shaped particles which, exclusive of both spherical particles and flake-like particles as defined below, have a surface area at least about 20 percent greater than the surface area of spherical particles but less than about 0.33 m 2 /gm, whereby said alloy, after amalgamation, retains a corrosion resistance comparable to that of spherical particles having substantially the same composition and having a surface area of about 0.21 m 2 /gm, but in any event, less than 0.22 m 2 /gm, while retaining handling characteristics comparable to those of flake-like particles also having substantially the same composition and having a surface area of at least about 0.33 m 2 /gm and approximately the same particle size and distribution as said randomly shaped particles.
Claim 9
Dependent Claim
155 words
A corrosion-resistant dental alloy in particulate form for use as a filling for dental cavities after amalgamation with mercury comprising a mixture of silver, tin and copper, said alloy consisting essentially of randomly shaped particles which, exclusive of both spherical particles and flake-like particles as defined below, have a surface area at least about 20 percent greater than the surface area of spherical particles but less than about 0.33 m 2 /gm, whereby said alloy, after amalgamation, retains a corrosion resistance comparable to that of spherical particles having substantially the same composition and having a surface area of about 0.21 m 2 /gm, but in any event, less than 0.22 m 2 /gm, while retaining handling characteristics comparable to those of flake-like particles also having substantially the same composition and having a surface area of at least about 0.33 m 2 /gm and approximately the same particle size and distribution as said randomly shaped particles.
Claim 10
Dependent Claim
47 words
The corrosion-resistant dental alloy of claim 7 wherein said mixture of silver, tin and copper comprises from about 47 to 70 percent by weight of silver, from about 20 to 32 percent by weight of tin and from about 7 to 27 percent by weight of copper.
Claim 11
Dependent Claim
19 words
The corrosion-resistant dental alloy of claim 7 having a surface area of less than about 0.31 m 2 /gm.
Claim 12
Dependent Claim
53 words
The corrosion-resistant dental alloy of claim 7 wherein said alloy particles have a mean particle size of between about 20 and 26.5 microns, and further wherein said particles have a particle size distribution such that substantially all of said particles fall within a particle size range of from about 1 to 72 microns.
Claim 13
Dependent Claim
30 words
The corrosion-resistant dental alloy of claim 10 wherein at least about 90% by weight of said particles fall within a particle size range of from about 10 to 52 microns.
Claim 14
Dependent Claim
28 words
The corrosion-resistant dental alloy of claim 7 wherein said alloy particles have a surface area at least about 30 percent greater than the surface area of spherical particles.
Claim 15
Dependent Claim
36 words
The corrosion-resistant dental alloy of claim 7 wherein said alloy particles have a surface area which is about 20-30 percent greater than the surface area of spherical particles but less than about 0.33 m 2 /gm.
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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) | 1983-11-25 | 1984-05-26 | 1984-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-25 | 1988-05-26 | 1988-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-25 | 1992-05-26 | 1992-11-25 | $7700.00 | Window Closed / Lapsed |