Lithium disilicate glass-ceramics
First Claim
1. A method of making a lithium disilicate dental product comprising:
- melting a starting glass composition at temperatures within the range of about 1200 to about 1600°
C.;
forming the molten glass into shaped blanks;
annealing the glass blanks at temperatures in the range of 300°
to about 600°
C. for a time in the range of about 15 minutes to about 8 hours;
subjecting the glass blanks to one or more heat treatments in the temperature range of from about 400°
to about 1100°
C. to convert the glass blanks into glass-ceramic blanks.
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Accused Products
Abstract
This invention is directed to lithium disilicate (Li2Si2O5) based glass-ceramics comprising silica, lithium oxide, alumina, potassium oxide and phosphorus pentoxide. The glass-ceramics are useful in the fabrication of single and multi-unit dental restorations (e.g. anterior bridges) made by heat pressing into refractory investment molds produced using lost wax techniques. The glass-ceramics have good pressability, i.e., the ability to be formed into dental articles by heat-pressing using commercially available equipment. In accordance with one embodiment directed to the process of making the glass-ceramics, the compositions herein are melted at about 1200° to about 1600° C., thereafter quenched (e.g., water quenched or roller quenched) or cast into steel molds, or alternately, cooled to the crystallization temperature. The resulting glass is heat-treated to form a glass-ceramic via a one or two step heat-treatment cycle preferably in the temperature range of about 400° to about 1100° C. The resulting glass-ceramics are then pulverized into powder and used to form pressable pellets and/or blanks of desired shapes, sizes and structures which are later pressed into dental restorations. Alternatively, instead of forming into pressable pellets or blanks, the pulverized powder is used to form a dental restoration using the refractory die technique or platinum foil technique.
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Citations
53 Claims
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1. A method of making a lithium disilicate dental product comprising:
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melting a starting glass composition at temperatures within the range of about 1200 to about 1600°
C.;
forming the molten glass into shaped blanks;
annealing the glass blanks at temperatures in the range of 300°
to about 600°
C. for a time in the range of about 15 minutes to about 8 hours;
subjecting the glass blanks to one or more heat treatments in the temperature range of from about 400°
to about 1100°
C. to convert the glass blanks into glass-ceramic blanks. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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42. A dental product comprising a glass-ceramic comprising:
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about 62 to about 85% SiO2;
about 1.5 to about 10% Al2O3;
about 8 to about 19% Li2O;
about 2.5 to about 7% K2O; and
about 0.5 to about 12% P2O5; and
wherein the 3-point flexure strength is greater than about 370 MPa. - View Dependent Claims (43)
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44. A dental product comprising a glass-ceramic comprising:
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about 64 to about 70% SiO2;
about 1.5 to about 6 Al2O3;
about 10 to about 15% Li2O;
about 2.5 to about 5% K2O; and
about 2 to about 7% P2O5; and
wherein the 3-point flexure strength is greater than about 370 MPa. - View Dependent Claims (45)
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46. A dental product comprising a glass-ceramic comprising:
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about 62 to about 85% SiO2;
about 5.1 to about 10 Al2O3;
about 8 to about 19% Li2O; and
about 0.5 to about 12% P2O5 and wherein the 3-point flexure strength is greater than about 370 MPa. - View Dependent Claims (47)
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48. A dental product comprising a glass-ceramic comprising:
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about 64 to about 70% SiO2;
about 5.2 to about 9 Al2O3;
about 10 to about 15% Li2O; and
about 2 to about 7% P2O5; and
wherein the 3-point flexure strength is greater than about 370 MPa. - View Dependent Claims (49)
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50. A dental product comprising a glass-ceramic comprising:
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about 64 to about 70% SiO2;
about 1.5 to about 6 Al2O3;
about 10 to about 15% Li2O;
about 2 to about 7% P2O5;
about 2.2 to about 5% K2O;
about 0.5 to about 3% Na2O; and
about 0.5 to about 3% B2O3 and wherein the 3-point flexure strength is greater than about 370 MPa. - View Dependent Claims (51)
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52. A dental product comprising a glass-ceramic comprising:
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about 62 to about 76% SiO2;
about 1.5 to about 10 Al2O3;
about 8 to about 19% Li2O;
about 0.3 to about 7% P2O5; and
about 0.5 to about 8% Ta2O5; and
wherein the 3-point flexure strength is greater than about 370 MPa. - View Dependent Claims (53)
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Specification