US4376835A
Expired / Lapsed
US
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Calcium depleted aluminum fluorosilicate glass powder for use in dental or bone cements
Assignee: SIH Stiftung and Co Industrie Holding KG
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Filing: 1982-01-04
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Granted: 1983-03-15
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Expires: 2002-01-04
Abstract
Abstract A calcium aluminum fluorosilicate glass powder is disclosed which has average particle size of at least 0.5 microns, and is characterized in that the calcium in the surface of the powder's particles is depleted so that the quotient of the atomic ratio Si/Ca at the surface of the particles and the atomic ratio Si/Ca in the core region of the particles is at least 2.0, more preferably at least 3.0 and most preferably at least 4.0. The glass powder may be prepared by surface treating calcium aluminum fluorosilicate glass powder particles with an acid which forms calcium salts, washing the calcium salts off the treated particles and drying the washed particles. The glass powder has utility in self-hardening glass ionomer cements, such as dental or bone cements. Cements formed from the glass powder exhibit reduced periods of water sensitivity, while permitting sufficient time for processing.
Inventors
- 👤 Werner Schmitt
- 👤 Robert Purrmann
- 👤 Peter Jochum
- 👤 Oswald Gasser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:20
CPC Classifications
C; C08; C08K; C08K3/00; C08K3/40; A; A61; A61K; A61K6/00; A61K6/80; A61K6/884; A61K6/887; A61K6/889; A61L; A61L24/00; A61L24/0047; A61L24/0073; A61L24/0089; C03; C03C; C03C12/00; C03C21/00; C03C21/001; C03C3/00; C03C3/04; C03C4/00; C03C4/0035; A61L2430/00; A61L2430/02; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/2933; Y10T428/2982; Y10T428/2991; Y10T428/2993; Y10T428/2996
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
128 words
A calcium aluminum fluorosilicate glass powder reactable with a mixing fluid to form a self hardening glass ionomer cement exhibiting properties of reduced period of water sensitivity and at the same time insuring a sufficiently long processing period, said glass powder being characterized by particles having an average size of at least 0.5 microns, and in that the level of calcium present at the surface of the powder particles is depleted relative to the level of the calcium present in the core region and to the extent that the quotient of the atomic ratio Si/Ca at the surface of the powder particles and the atomic ratio Si/Ca in the core region is at least 2.0, with the calcium content increasing asymptotically from the surface to the core region.
Claim 2
Dependent Claim
128 words
A calcium aluminum fluorosilicate glass powder reactable with a mixing fluid to form a self hardening glass ionomer cement exhibiting properties of reduced period of water sensitivity and at the same time insuring a sufficiently long processing period, said glass powder being characterized by particles having an average size of at least 0.5 microns, and in that the level of calcium present at the surface of the powder particles is depleted relative to the level of the calcium present in the core region and to the extent that the quotient of the atomic ratio Si/Ca at the surface of the powder particles and the atomic ratio Si/Ca in the core region is at least 2.0, with the calcium content increasing asymptotically from the surface to the core region.
Claim 3
Dependent Claim
48 words
The glass powder of claim 1 having a core region comprising: 20-60 weight percent SiO 2 , 10-50 weight percent Al 2 O 3 , 1-40 weight percent CaO, 1-40 weight percent F, 0-10 weight percent Na 2 O, and 0-10 weight percent P 2 O 5 .
Claim 4
Dependent Claim
34 words
The glass powder of claim 2 further comprising 0-20% by weight of an oxide of the group consisting of B, Bi, Zn, Mg, Sn, Ti, Zr, La, a trivalent lanthanide, K, W and Ge.
Claim 5
Dependent Claim
51 words
The glass powder of claim 3 wherein the oxides are selected from the group consisting of B 2 O 3 , Bi 2 O 3 , ZnO, MgO, SnO 2 , TiO 2 , ZrO 2 , La 2 O 3 , K 2 O, WO 3 and GeO 2 .
Claim 6
Dependent Claim
48 words
The glass powder of claim 2 having a core region comprising: 25-50 weight percent SiO 2 , 10-40 weight percent Al 2 O 3 , 10-35 weight percent CaO, 5-30 weight percent F, 0-8 weight percent Na 2 O, and 1-10 weight percent P 2 O 5 .
Claim 7
Dependent Claim
34 words
The glass powder of claim 5 further comprising 0-10 weight percent of an oxide of the group consisting of B, Bi, Zn, Mg, Sn, Ti, Zr, La, a trivalent lanthanide, K, W and Ge.
Claim 8
Dependent Claim
48 words
The glass powder of claim 2 having a core region comprising: 25-45 weight percent SiO 2 , 20-40 weight percent Al 2 O 3 , 10-30 weight percent CaO, 10-30 weight percent F, 1-8 weight percent Na 2 O, and 1-10 weight percent P 2 O 5 .
Claim 9
Dependent Claim
13 words
The glass powder of claim 1 wherein the quotient is at least 3.0.
Claim 10
Dependent Claim
13 words
The glass powder of claim 1 wherein the quotient is at least 4.0.
Claim 11
Dependent Claim
21 words
The glass powder of claim 1 wherein the surface calcium depletion extends to a depth of at least about 10 nm.
Claim 12
Dependent Claim
18 words
The glass powder of claim 10 wherein the depletion extends to a depth of at least 20 nm.
Claim 13
Dependent Claim
18 words
The glass powder of claim 10 wherein the depletion extends to a depth of at least 100 nm.
Claim 14
Dependent Claim
17 words
The glass powder of claim 10 wherein the depletion extends to a depth of about 200-300 nm.
Claim 15
Dependent Claim
16 words
The glass powder of claim 1 wherein the average particle size is at least 1 micron.
Claim 16
Dependent Claim
16 words
The glass powder of claim 1 wherein the average particle size is at least 3 microns.
Claim 17
Dependent Claim
14 words
The glass powder of claim 1 wherein the maximum particle size is 150 microns.
Claim 18
Dependent Claim
14 words
The glass powder of claim 1 wherein the maximum particle size is 100 microns.
Claim 19
Dependent Claim
33 words
A self-hardening glass ionomer cement comprising an aqueous mixture of the calcium aluminum fluorosilicate glass powder of claim 1 having a maximum particle size of 150 microns, a polycarboxylic acid and chelating agent.
Claim 20
Dependent Claim
24 words
The cement of claim 18 wherein the average particle size of the powder is 1-20 microns and the maximum particle size is 100 microns.
Claim 21
Dependent Claim
24 words
The cement of claim 19 wherein the average particle size of the powder is 3-10 microns and the maximum particle size is 60 microns.
Claim 22
Dependent Claim
13 words
The cement of claim 18 wherein the maximum particle size is 25 microns.
Claim 23
Dependent Claim
13 words
The cement of claim 18 wherein the maximum particle size is 20 microns.
Claim 24
Dependent Claim
10 words
A dental filling material comprising the cement of claim 18.
Claim 25
Dependent Claim
10 words
A dental filling material comprising the cement of claim 19.
Claim 26
Dependent Claim
10 words
A dental filling material comprising the cement of claim 20.
Claim 27
Dependent Claim
10 words
A dental filling material comprising the cement of claim 21.
Claim 28
Dependent Claim
10 words
A dental filling material comprising the cement of claim 22.
Claim 29
Dependent Claim
10 words
A dental bonding cement comprising the cement of claim 21.
Claim 30
Dependent Claim
9 words
A bone cement comprising the cement of claim 18.
Claim 31
Dependent Claim
10 words
A dental bonding cement comprising the cement of claim 22.
References Cited (Backward Citations)
US3814717A
Cited
US3986998A
Cited
US4209434A
Cited
US4063001A
Cited
US4215033A
Cited
US4271057A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-03-14 | 1986-09-13 | 1987-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-03-14 | 1990-09-13 | 1991-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-03-14 | 1994-09-13 | 1995-03-15 | $7700.00 | Window Closed / Lapsed |