Patent US4861808A successfully refreshed from Google Patents.
US4861808A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Glass/poly (carboxylic acid) cement compositions
Assignee: Dentsply Ltd
•
Filing: 1988-07-07
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Granted: 1989-08-29
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Expires: 2008-07-07
Abstract
Abstract A process for producing a radiopaque cement comprises reacting a polymer containing free carboxyl groups (generally a homo or copolymer of acrylic acid) with a particulate acid-leachable source of polyvalent metal ions (such as an acid-leachable glass) in the presence of water and strontium fluoride.
Inventors
- 👤 Richard W. Billington
- 👤 Jill A. Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:51
CPC Classifications
A; A61; A61K; A61K6/00; A61K6/80; A61K6/884; A61K6/887; A61K6/889
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
22 words
A prepolymer composition comprising one or more ethylenically unsaturated compounds, particulate filler, and strontium in which strontium is present as strontium fluoride.
Claim 2
Dependent Claim
22 words
A prepolymer composition comprising one or more ethylenically unsaturated compounds, particulate filler, and strontium in which strontium is present as strontium fluoride.
Claim 3
Dependent Claim
43 words
A prepolymer composition comprising one or more ethylenically unsaturated compounds, particulate filler, and strontium said prepolymer composition comprising an acid or alkali-leachable source of polyvalent metal ions, and a homopolymer or copolymer of acrylic acid having a molecular weight of 20,000 to 125,000.
Claim 4
Dependent Claim
43 words
A prepolymer composition comprising one or more ethylenically unsaturated compounds, particulate filler, and strontium said prepolymer composition comprising an acid or alkali-leachable source of polyvalent metal ions, and a homopolymer or copolymer of acrylic acid having a molecular weight of 20,000 to 125,000.
Claim 5
Dependent Claim
80 words
The prepolymer composition of claim 2 which comprises an acid or alkali-leachable source of polyvalent metal ions, a homopolymer or copolymer of acrylic acid having a molecular weight of 20,000 to 125,000 wherein said leachable source comprises about 15-33% SrF 2 , 0-25% CaO, 28-38% Al 2 O 3 , 25-30% SiO 2 , 0-9% P 2 O 5 wherein the ratio of said homopolymer or copolymer to said leachable source is between 0.15 to 1 and 0.5 to 1.
Claim 6
Dependent Claim
18 words
The prepolymer of claim 2 which is a homopolymer having a molecular weight of from 35,000 to 70,000.
Claim 7
Dependent Claim
23 words
A prepolymer composition which is adapted for use as a sealant which comprises calcium fluoroaluminosilicate glass, polyacrylic acid, tartaric acid and strontium fluoride.
Claim 8
Dependent Claim
23 words
A prepolymer composition which is adapted for use as a sealant which comprises calcium fluoroaluminosilicate glass, polyacrylic acid, tartaric acid and strontium fluoride.
Claim 9
Dependent Claim
40 words
The prepolymer composition of claim 5 which is adapted for use as a sealant which comprises glass filler having a mean particle size of 5 μm, polyacrylic acid having a molecular weight of about 45,000, tartaric acid and strontium fluoride.
Claim 10
Dependent Claim
55 words
The prepolymer composition of claim 5 which is adapted for use as sealant which comprises (a) about 62% by weight calcium fluoroaluminosilicate glass having a mean diameter of about 5 μm, (b) about 15% polyacrylic acid powder having a molecular weight of about 45,000, (c) about 1.3% tartaric acid, and (d) about 21.5% strontium fluoride.
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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) | 1992-08-28 | 1993-02-27 | 1993-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-28 | 1997-02-27 | 1997-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-28 | 2001-02-27 | 2001-08-29 | $7700.00 | Window Closed / Lapsed |