US4431420A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Glass-ceramic dental products
Assignee: Corning Glass Works
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Filing: 1982-04-30
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Granted: 1984-02-14
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Expires: 2002-04-30
Abstract
Abstract Precision dental tools, models, appliances, prostheses, and attachments are produced by providing a glass body of selected conformation, and then heat treating the glass body to yield a glass-ceramic component of superior characteristics wherein tetrasilicic fluormica constitutes the predominant crystal phase.
Inventors
- 👤 Peter J. Adair
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:20
CPC Classifications
A; A61; A61C; A61C13/00; A61C13/0003; A61C3/00; A61K; A61K6/00; A61K6/70; A61K6/78; A61K6/80; A61K6/802; A61K6/807; A61K6/824; A61K6/831; A61K6/833
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
141 words
A glass-ceramic dental construct containing tetrasilicic fluormica as the predominant crystal phase and having surfaces that conform to and are in contact with living dental tissue, a modulus of rupture greater than 8000 psi and consisting, in weight percent on the oxide basis, of K 2 : 10-18 MgO: 14-19 SiO 2 :55-65 Al 2 O 3 :0-2 ZrO 2 : 0-7 F: 4-9 said dential construct having a coefficient of thermal expansion and a thermal conductivity approximating those of tooth enamel, a visual appearance similar to that of tooth enamel, as evidenced by a level of translucency between 0.4-0.8 determined by reflectance measurements and resistance to food staining and chemical attack in an oral environment as evaluated by a level of K 2 O extracted not exceeding 10 micrograms/cm 2 after exposure for four hours to water at 95° C.
Claim 2
Dependent Claim
141 words
A glass-ceramic dental construct containing tetrasilicic fluormica as the predominant crystal phase and having surfaces that conform to and are in contact with living dental tissue, a modulus of rupture greater than 8000 psi and consisting, in weight percent on the oxide basis, of K 2 : 10-18 MgO: 14-19 SiO 2 :55-65 Al 2 O 3 :0-2 ZrO 2 : 0-7 F: 4-9 said dential construct having a coefficient of thermal expansion and a thermal conductivity approximating those of tooth enamel, a visual appearance similar to that of tooth enamel, as evidenced by a level of translucency between 0.4-0.8 determined by reflectance measurements and resistance to food staining and chemical attack in an oral environment as evaluated by a level of K 2 O extracted not exceeding 10 micrograms/cm 2 after exposure for four hours to water at 95° C.
References Cited (Backward Citations)
US3689293A
Cited
US3732087A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-02-13 | 1987-08-15 | 1988-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-13 | 1991-08-15 | 1992-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-13 | 1995-08-15 | 1996-02-14 | $7700.00 | Window Closed / Lapsed |