US4814362A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Glasses and poly(carboxylic acid) cement compositions containing them
Assignee: Dentsply Ltd
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Filing: 1987-04-06
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Granted: 1989-03-21
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Expires: 2007-04-06
Abstract
Abstract Alkaline earth metal aluminofluorosilicate glasses suitable for use as ion-sources in the poly(carboxylic acid) cement compositions contain strontium in order to provide radiopacity. The invention also provides methods for making poly(carboxylate) cement using the glasses of the invention as ion-sources.
Inventors
- 👤 Richard W. Billington
- 👤 Jill A. Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 23:05
CPC Classifications
C; C03; C03C; C03C4/00; C03C4/0035; A; A61; A61K; A61K6/00; A61K6/80; A61K6/884; A61K6/887; A61K6/889; C03C3/00; C03C3/04; C03C3/076; C03C3/11; C03C3/112
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
94 words
A method of preparing a radioopaque cross-linked poly (carboxylate) dental cement comprising the steps of: (a) preparing glass using components wherein strontium provides substantially all radioopaque properties in said glass, said glass being suitable as a fluoride ion source in said cement (b) blending said glass with 20,000 to 125,000 molecular weight polyacrylic acid to provide a powder blend of glass and polyacrylic acid (c) mixing said blend of glass and polyacrylic acid with water to produce a dental cement having a radiopacity at least substantially equivalent to that of dentin or dental enamel.
Claim 2
Independent Claim
94 words
A method of preparing a radioopaque cross-linked poly (carboxylate) dental cement comprising the steps of: (a) preparing glass using components wherein strontium provides substantially all radioopaque properties in said glass, said glass being suitable as a fluoride ion source in said cement (b) blending said glass with 20,000 to 125,000 molecular weight polyacrylic acid to provide a powder blend of glass and polyacrylic acid (c) mixing said blend of glass and polyacrylic acid with water to produce a dental cement having a radiopacity at least substantially equivalent to that of dentin or dental enamel.
Claim 3
Dependent Claim
44 words
The method of claim 1 which comprises preparing said glass to consist essentially of by weight about 5-35% SrO, 25-40% Al 2 O 3 , 23-33% SiO 2 , 0-10% F 2 , 1-7% Na 2 O, and 0-10% P 2 O 5 .
Claim 4
Dependent Claim
23 words
The method of claim 1 which comprises providing said polyacrylic acid as a homopolymer of acrylic acid having a molecular weight of 35,000-70,000.
Claim 5
Dependent Claim
25 words
The method of claim 1 in which said glass is pulverized, ground, and/or milled to have a particle size of from 0.5 to 60 μm.
Claim 6
Dependent Claim
40 words
The method of claim 1 which comprises blending said glass and said polyacrylic acid in a weight ratio of polyacrylic acid to glass of from 0.12:1 to 0.4:1 and the weight ratio of water to glass is 0.4:1 to 0.1:1.
Claim 7
Dependent Claim
39 words
The method of claim 1 which comprises the further step of including a hydroxycarboxylic acid in the mixing step, said hydroxycarboxylic acid serving to alter or modify the working time or setting time of the cementing reaction or both.
Claim 8
Dependent Claim
18 words
The method of claim 6 which comprises using tartaric acid to decrease the setting time of the reaction.
Claim 9
Dependent Claim
22 words
The method of claim 1 in which said glass is prepared to be substantially free of alkaline earth metals other than strontium.
Claim 10
Dependent Claim
31 words
The method of claim 1 which comprises adding strontium fluoride to said glass composition in preparing said glass, said fluoride acting as a leachable ion, and strontium acting as radioopacifying agent.
Claim 11
Dependent Claim
24 words
The method of claim 1 which produces a dental cement having a radioopacity of about 0.6 to 2.8 mm aluminum per mm of cement.
References Cited (Backward Citations)
FR2246589A1
Cited
US4032504A
Cited
WO1980000409A1
Cited
US4215033A
Cited
DE3000118A1
Cited
US4492777A
Cited
US4527979A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-03-20 | 1992-09-19 | 1993-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-20 | 1996-09-19 | 1997-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-20 | 2000-09-19 | 2001-03-21 | $7700.00 | Window Closed / Lapsed |