US3761728A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of forming dental restorations
Assignee: STAR DENTAL LABOR
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Filing: 1972-07-20
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Granted: 1973-09-25
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Expires: 1992-07-20
Abstract
Abstract A restoration is made using an alloy of approximately 80% Ni 20% Cr employing conventional casting techniques heretofore used with precious metals. After the casting has been cleaned it is heated under vacuum commencing at 1,400*-1,500*F. and increasing gradually to approximately 1950*F. The vacuum is released and the casting cooled - a grayish blue colored compound forming on the surface. Porosities and casting defects may be conveniently repaired using ceramic gold paste. The metal may be soldered, to other metal members, whether of the same alloy or gold or any other conventional metal. Porcelain is then applied, again using conventional techniques. The product is characterized by the very good bond of porcelain to metal, extreme dimensional accuracy and relatively low cost of metal.
Inventors
- 👤 J Kochavi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:14
CPC Classifications
C; C22; C22C; C22C19/00; A; A61; A61C; A61C13/00; A61C13/0003; A61C5/00; A61C5/70; A61C5/77; A61K; A61K6/00; A61K6/80; A61K6/802; A61K6/84; A61K6/844; C22C1/00; C22C1/02; C22C1/023; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49567; Y10T29/49718; Y10T29/49746; Y10T29/49972; Y10T29/4998; Y10T29/49988
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
117 words
A method according to claim 1 in which said step of preparing an investment mold comprises forming a plaster die representative of the tooth in the patient''s mouth, applying wax to said die to a thickness approximately equal to the frame to be formed, removing said wax from said die, mounting said wax inverted on the base of a casting mold, fitting a casting ring on said base, mixing investment material and filling said ring with said material, removing said base after said material has set, and heating said ring and material to harden said investment material and melt out said wax to form a cavity in said investment material complementary to the casting to be formed.
Claim 2
Dependent Claim
52 words
A method according to claim 2 in which said mounting step includes attaching to the wax a cylindrical wax sprue of a length such that when said sprue is attached to said base during said mounting step the top of said wax is about one-fourth inch below the top of said ring.
Claim 3
Dependent Claim
69 words
A method according to claim 1 in which said heating step includes heating said pellet with a torch while said crucible is positioned at the center of the table of a centrifugal casting machine, said crucible former also being placed on said table, said casting step comprising revolving said table to cause the molten alloy to flow out of said crucible and into the cavity of said crucible former.
Claim 4
Dependent Claim
53 words
A method according to claim 1 which further comprises repairing imperfections and porosities in said casting before said step of heating said casting by filling said imperfections and porosities with ceramic gold cream, then heating the casting to about 1,600*-2,000* F. to form a ceramic gold, then smoothing off the surplus ceramic gold.
Claim 5
Dependent Claim
92 words
A method according to claim 1 in which said step of applying porcelain comprises first applying an opaque coating to said casting by mixing opaque coating powder and water to form an opaque paste, coating portions of said casting with said opaque paste, drying and then heating said opaque coated casting, then applying at least one coating of porcelain enamel over the opaque coating by mixing porcelain powder and water, brushing the mixture onto the opaque, drying the porcelain, and heating the casting to about 1,600*-2,000* F. to form a porcelain coating.
Claim 6
Dependent Claim
108 words
A method according to claim 1 in which said step of applying porcelain comprises first applying an opaque coating by mixing opaque coating powder and oil and applying the opaque mixture to portions of the casting, drying the opaque mixture, then heating the casting under high vacuum in a furnace from an initial temperature of about 1,400* F. to a final temperature of about 1, 800*-1,900* F., then applying at least one coating of porcelain enamel over the opaque coating by mixing porcelain powder and water, brushing the mixture onto the opaque, drying the porcelain and heating the casting to about 1,600*-2,000* F. to form a porcelain coating.
Claim 7
Dependent Claim
89 words
A method according to claim 1 in which said step of applying porcelain comprises first applying a layer of ceramic gold cream to portions of said casting, drying said layer, and heating said casting to about 1,800*-1,900* F. to form a gold layer on portions of said casting, then applying at least one coating of porcelain enamel over said gold layer by mixing porcelain powder and water, brushing the mixture onto said layer, drying the porcelain, and heating the casting to about 1,600*-2,000* F. to form a porcelain coating.
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) | 1976-09-24 | 1977-03-26 | 1977-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-24 | 1981-03-26 | 1981-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-24 | 1985-03-26 | 1985-09-25 | $7700.00 | Window Closed / Lapsed |