US3973970A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Additive composition for making dental materials
Assignee: United States Department of Health and Human Services
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Filing: 1975-01-07
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Granted: 1976-08-10
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Expires: 1995-01-07
Abstract
Abstract Addition of ammonium stabilized colloidal silica, borax and boric acid to the distilled water in which dental porcelain is fired greatly increases the firing range by reducing "balling" or edge rounding, and flow deformation. Greatly increased machinability and indefinitely prolonged green-biscuit strength is also obtained by the use the present additive without deleterious effects on the porcelain.
Inventors
- 👤 Curtis P. Mabie
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 03:18
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/622; C04B35/626; C04B35/63; C04B35/6303; C04B35/6316; A; A61; A61K; A61K6/00; A61K6/80; A61K6/802; A61K6/849; A61K6/867
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
67 words
In the method of making dental porcelain products, comprising making a paste of a liquid product and raw porcelain powder, compressing and firing to a temperature sufficient to bond the mixture into a mature porcelain, the improvement wherein said liquid product comprises a composition comprising an aqueous solution of a colloidal silica and/or alumina sol and a water soluble flux which is compatible with the colloid used.
Claim 2
Dependent Claim
67 words
In the method of making dental porcelain products, comprising making a paste of a liquid product and raw porcelain powder, compressing and firing to a temperature sufficient to bond the mixture into a mature porcelain, the improvement wherein said liquid product comprises a composition comprising an aqueous solution of a colloidal silica and/or alumina sol and a water soluble flux which is compatible with the colloid used.
Claim 3
Dependent Claim
19 words
A method in accordance with claim 1, wherein said colloidal silica and/or aluminum sol is ammonium stabilized silica sol.
Claim 4
Dependent Claim
18 words
A method in accordance with claim 2, wherein said flux is a combination of boric acid and borax.
Claim 5
Dependent Claim
44 words
A method in accordance with claim 3, wherein said composition comprises 1 to 8% ammonium stabilized colloidal silica and 0.5 to 1.5% flux, wherein said flux comprises boric acid and borax with a weight ratio of boric acid to borax of 0.1-1.5 : 1.
Claim 6
Dependent Claim
13 words
The dental porcelain product made in accordance with the method of claim 4.
Claim 7
Dependent Claim
56 words
A green biscuit for firing into a porcelain dental product comprising a compressed paste of raw dental porcelain powder and a composition comprising 1 to 8% ammonium stabliized colloidal silica and 0.5 to 1.5% flux, wherein said flux comprises boric acid and borax with a weight ratio of boric acid to borax of 0.1-1.5 : 1.
Claim 8
Dependent Claim
56 words
A green biscuit for firing into a porcelain dental product comprising a compressed paste of raw dental porcelain powder and a composition comprising 1 to 8% ammonium stabliized colloidal silica and 0.5 to 1.5% flux, wherein said flux comprises boric acid and borax with a weight ratio of boric acid to borax of 0.1-1.5 : 1.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-10 | 1980-02-09 | 1980-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-10 | 1984-02-09 | 1984-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-10 | 1988-02-09 | 1988-08-10 | $7700.00 | Window Closed / Lapsed |