Lithium disilicate glass-ceramics

• US 20030073563A1
• Filed: 06/25/2002
• Published: 04/17/2003
• Est. Priority Date: 12/11/1998
• Status: Active Grant

• Current Assignee: Ardent, Inc. (Ivoclar Vivadent AG)
• Original Assignee: Pentron Ceramics, Inc.
• Inventors: Panzera, Carlino, Brodkin, Dmitri, Panzera, Paul
• Granted Patent: US 6,802,894 B2
• Time in Patent Office: Days
• US Class Current: 501/5
• CPC Class Codes: A61K 6/17 Particle size
• CPC Class Codes: A61K 6/20 Protective coatings for natural or artificial teeth, e.g. sealings, dye coatings or varnish
• CPC Class Codes: A61K 6/78 Pigments
• CPC Class Codes: A61K 6/807 comprising magnesium oxide
• CPC Class Codes: A61K 6/822 comprising rare earth metal oxides
• CPC Class Codes: A61K 6/824 comprising transition metal oxides
• CPC Class Codes: A61K 6/833 Glass-ceramic composites
• CPC Class Codes: C03B 19/06 by sintering, e.g. by cold isostatic pressing of powders and subsequent sintering, by hot pressing of powders, by sintering slurries or dispersions not undergoing a liquid phase reaction
• CPC Class Codes: C03B 32/02 Thermal crystallisation, e.g. for crystallising glass bodies into glass-ceramic articles C03B27/012 takes precedence
• CPC Class Codes: C03C 10/0027 containing SiO2, Al2O3, Li2O as main constituents
• CPC Class Codes: C03C 3/097 containing phosphorus, niobium or tantalum
• CPC Class Codes: C03C 4/0021 for dental use

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.

Claims

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.

2. The method of claim 1 wherein the blanks are in the shape of pellets.

3. The method of claim 1 wherein the blanks are in the shape of rods.

4. The method of claim 2 comprising:

pressing the blanks into the dental product.

5. The method of claim 1 wherein crystallization of lithium disilicate is effected in the glass blanks after annealing when subjected to one or more heat treatments in the temperature range of from about 400°

to about 1100°

C.

6. The method of claim 1 wherein subjecting the glass blanks to one or more heat treatments in the temperature range of from about 400°

to about 1100°

C. comprises a first nucleation step and a second crystal growth step.

7. The method of claim 6 wherein the first nucleation step comprises heating the molten glass to a temperature in the range of about 450°

to about 700°

C.

8. The method of claim 6 wherein the second crystal growth step comprises heating the nucleated glass in the range of about 800°

to about 1000°

C.

9. The method of claim 6 wherein the first nucleation step comprises heating the molten glass to a temperature in the range of about 500°

to about 650°

C.

10. The method of claim 6 wherein the second crystal growth step comprises heating the nucleated glass in the range of about 830°

to about 930°

C.

11. The method of claim 6 wherein the first nucleation step comprises about a one hour soak at about 645°

C. and wherein the second crystal growth step comprises about a four hour soak at about 850°

C.

12. The method of claim 1 comprising machining the glass-ceramic blanks into the dental product.

13. The method of claim 4 wherein the dental product is a dental core and is provided with one or more coatings.

14. The method of claim 13 wherein the one or more coatings is selected from a ceramic, a sintered ceramic, a glass-ceramic, a porcelain, a glass, a glaze, a composite and mixtures thereof.

15. The method of claim 13 wherein the one or more coatings has a firing temperature in the range of about 700°

to about 900°

C. and a coefficient of thermal expansion (measured from room temperature to its transition temperature) of within about ±

2.0×

10<sup>−

6</sup>/°

C. of the dental product (measured at the same temperature range).

16. The dental product of claim 4 formed into a component selected from the group consisting of orthodontic appliances, bridges, space maintainers, tooth replacement appliances, splints, crowns, partial crowns, dentures, posts, teeth, jackets, inlays, onlays, facing, veneers, facets, implants, abutments, cylinders, and connectors.

17. The method of claim 1 wherein the glass-ceramic comprises in weight percent:

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.

18. The method of claim 17 wherein the glass-ceramic further comprises in weight percent:

up to about 4.9% B₂O₃;

up to about 1.5% F;

up to about 5% ZnO;

up to about 7% CaO;

up to about 2% MgO;

up to about 7% BaO;

up to about 1% SrO;

up to about 5% Cs₂O;

up to about 5% Na₂O;

up to about 2% TiO₂;

up to about 3% ZrO₂;

up to about 1% SnO₂;

up to about 1% Sb₂O₃;

up to about 1% Sb₂O₃;

up to about 3% Y₂O₃;

up to about 1% CeO₂;

up to about 1% Eu₂O₃;

up to about 1% Tb₂O₇;

up to about 2% Nb₂O₅;

up to about 2% Ta₂O₅; and

wherein the molar ratio of (Na₂O +K₂O+CaO+SrO+BaO)/(Al₂O₃+ZnO) ≧

1.3.

19. The method of claim 1 wherein the glass-ceramic comprises in weight percent:

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.

20. The method of claim 19 wherein the glass-ceramic further comprises in weight percent:

up to about 1.5% F;

up to about 7% BaO;

up to about 1% SrO;

up to about 5% Cs₂O;

up to about 2.7% B₂O₃;

up to about 2% ZnO;

up to about 0.9% CaO;

up to about 2% MgO;

up to about 3% Na₂O;

up to about 2% TiO₂;

up to about 3% ZrO₂;

up to about 1% SnO₂;

up to about 1% Sb₂O₃;

up to about 3% Y₂O₃;

up to about 1% CeO₂;

up to about 1% Eu₂O₃;

up to about 1% Tb₄O₇;

up to about 2% Nb₂O₅; and

up to about 2% Ta₂O₅.

21. The method of claim 1 wherein the glass-ceramic comprises in weight percent:

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.

22. The method of claim 21 wherein the glass-ceramic further comprises in weight percent:

up to about 7% K₂O;

up to about 1.5% F;

up to about 7% BaO;

up to about 1% SrO;

up to about 5% Cs₂O;

up to about 4.9% B₂O₃;

up to about 5% ZnO;

up to about 7% CaO;

up to about 2% MgO;

up to about 5% Na₂O;

up to about 2% TiO₂;

up to about 3% ZrO₂;

up to about 1% SnO₂;

up to about 1% Sb₂O₃;

up to about 3% Y₂O₃;

up to about 1% CeO₂;

up to about 1% Eu₂O₃;

up to about 1% Tb₄O₇;

up to about 2% Nb₂O₅; and

up to about 2% Ta₂O₅.

23. The method of claim 1 wherein the glass-ceramic comprises in weight percent:

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.

24. The method of claim 23 wherein the glass-ceramic further comprises in weight percent:

up to about 1.5% F;

up to about 7% BaO;

up to about 1% SrO;

up to about 5% Cs₂O;

up to about 5% K₂O;

up to about 2.7% B₂O₃;

up to about 2% ZnO;

up to about 0.9% CaO;

up to about 2% MgO;

up to about 3% Na₂O;

up to about 2% TiO₂;

up to about 3% ZrO₂;

up to about 1% SnO₂;

up to about 1% Sb₂O₃;

up to about 3% Y₂O₃;

up to about 1% CeO₂;

up to about 1% Eu₂O₃;

up to about 1% Tb₄O₇;

up to about 2% Nb₂O₅; and

up to about 2% Ta₂O₅.

25. The method of claim 1 wherein the glass-ceramic comprises in weight percent:

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.

26. The method of claim 25 wherein the glass-ceramic further comprises in weight percent:

up to about 1.5% F;

up to about 7% BaO;

up to about 1% SrO;

up to about 5% Cs₂O;

up to about 0.9% CaO;

up to about 2% TiO₂;

up to about 3% ZrO₂;

up to about 1% SnO₂;

up to about 1% Sb₂O₃;

up to about 3% Y₂O₃;

up to about 1% CeO₂;

up to about 1% Eu₂O₃;

up to about 1% Tb₄O₇;

up to about 2% Nb₂O₅; and

up to about 2% Ta₂O₅.

27. The method of claim 1 wherein the glass-ceramic comprises in weight percent:

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.

28. The glass-ceramic composition of claim 27 further comprising in weight percent:

up to about 5% B₂O₃.

up to about 5% Na₂O;

up to about 7% K₂O;

up to about 1.5% F;

up to about 5% ZnO;

up to about 2% MgO;

up to about 7% BaO;

up to about 1% SrO;

up to about 5% Cs₂O;

up to about 7% CaO;

up to about 2% TiO₂;

up to about 3% ZrO₂;

up to about 1% SnO₂;

up to about 1% Sb₂O₃;

up to about 3% Y₂O₃;

up to about 1% CeO₂;

up to about 1% Eu₂O₃;

up to about 1% Tb₄O₇; and

up to about 2% Nb₂O₅.

29. The method of claim 1 wherein the glass-ceramic comprises in weight percent:

about 68.8% SiO₂;

about 1.3% B₂O₃;

about 4.8% Al₂O₃;

about 1.0% CaO;

about 2.8% BaO;

about 14.4% Li₂O;

about 2.2% K₂O;

about 1.5% Na₂O; and

about 3.3% P₂O₅.

30. The method of claim 1 wherein the glass-ceramic comprises in weight

about 67.2% SiO₂;

about 1.2% B₂O₃;

about 4.7% Al₂O₃;

about 1.0% CaO;

about 2.7% BaO;

about 14.1% Li₂O;

about 2.2% K₂O;

about 1.4% Na₂O;

about 3.2% P₂O₅;

about 0.4% CeO₂; and

about 2% Ta₂O₅.

31. The method of claim 1 further comprising:

batching the starting glass composition prior to melting; and

adding additives to the starting glass composition.

32. The method of claim 31 wherein the additives comprise a pigment.

33. The method of claim 32 wherein the pigment comprises CeO₂, Tb₄O₇, MnO₂, V₂O₅, NiO₂, TiO₂, or a mixture thereof.

34. The method of claim 1 wherein the shaped blanks are formed by:

pouring the molten glass into molds to form the blanks; and

removing the glass blanks from the molds after the blanks have hardened.

35. The method of claim 1 wherein the blanks are formed by:

drawing glass rods from the molten glass melt; and

sectioning the rods into the blanks.

36. A dental restoration made with the glass-ceramic blanks of claim 1.

37. The dental restoration of claim 36 comprising a high strength reinforcing bar.

38. The dental restoration of claim 37 wherein the high strength reinforcing bar comprises zirconia.

39. The dental restoration of claim 36 wherein the high strength reinforcing bar further comprises yttria.

40. The dental restoration of claim 36 wherein the blank comprises a 3-point flexure strength exceeding about 350 MPa.

41. The dental restoration of claim 40 wherein the 3-point flexure strength is greater than about 370 MPa.

42. A dental product comprising a glass-ceramic comprising:

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.

43. The dental product of claim 42 wherein the glass-ceramic further comprises:

up to about 4.9% B₂O₃;

up to about 1.5% F;

up to about 5% ZnO;

up to about 7% CaO;

up to about 2% MgO;

up to about 7% BaO;

up to about 1% SrO;

up to about 5% Cs₂O;

up to about 5% Na₂O;

up to about 2% TiO₂;

up to about 3% ZrO₂;

up to about 1% SnO₂;

up to about 1% Sb₂O₃;

up to about 1% Sb₂O₃;

up to about 3% Y₂O₃;

up to about 1% CeO₂;

up to about 1% Eu₂O₃;

up to about 1% Tb₂O₇;

up to about 2% Nb₂O₅;

up to about 2% Ta₂O₅; and

wherein the molar ratio of (Na₂O+K₂O+CaO+SrO+BaO)/(Al₂O₃+ZnO)≧

1.3.

44. A dental product comprising a glass-ceramic comprising:

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.

45. The dental product of claim 44 wherein the glass-ceramic further comprises:

up to about 1.5% F;

up to about 7% BaO;

up to about 1% SrO;

up to about 5% Cs₂O;

up to about 2.7% B₂O₃;

up to about 2% ZnO;

up to about 0.9% CaO;

up to about 2% MgO;

up to about 3% Na₂O;

up to about 2% TiO₂;

up to about 3% ZrO₂;

up to about 1% SnO₂;

up to about 1% Sb₂O₃;

up to about 3% Y₂O₃;

up to about 1% CeO₂;

up to about 1% Eu₂O₃;

up to about 1% Tb₄O₇;

up to about 2% Nb₂O₅; and

up to about 2% Ta₂O₅.

46. A dental product comprising a glass-ceramic comprising:

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.

47. The dental product of claim 46 wherein the glass-ceramic further comprises:

up to about 7% K₂0;

up to about 1.5% F;

up to about 7% BaO;

up to about 1% SrO;

up to about 5% Cs₂O;

up to about 4.9% B₂O₃;

up to about 5% ZnO;

up to about 7% CaO;

up to about 2% MgO;

up to about 5% Na₂O;

up to about 2% TiO₂;

up to about 3% ZrO₂;

up to about 1% SnO₂;

up to about 1% Sb₂O₃;

up to about 3% Y₂O₃;

up to about 1% CeO₂;

up to about 1% Eu₂O₃;

up to about 1% Tb₄O₇;

up to about 2% Nb₂O₅; and

up to about 2% Ta₂O₅.

48. A dental product comprising a glass-ceramic comprising:

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.

49. The dental product of claim 48 wherein the glass-ceramic further comprises:

up to about 1.5% F;

up to about 7% BaO;

up to about 1% SrO;

up to about 5% Cs₂O;

up to about 5% K₂O;

up to about 2.7% B₂O₃;

up to about 2% ZnO;

up to about 0.9% CaO;

up to about 2% MgO;

up to about 3% Na₂O;

up to about 2% TiO₂;

up to about 3% ZrO₂;

up to about 1% SnO₂;

up to about 1% Sb₂O₃;

up to about 3% Y₂O₃;

up to about 1% CeO₂;

up to about 1% Eu₂O₃;

up to about 1% Tb₄O₇;

up to about 2% Nb₂O₅; and

up to about 2% Ta₂O₅.

50. A dental product comprising a glass-ceramic comprising:

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.

51. The dental product of claim 50 wherein the glass-ceramic further comprises:

up to about 1.5% F;

up to about 7% BaO;

up to about 1% SrO;

up to about 5% Cs₂O;

up to about 0.9% CaO;

up to about 2% TiO₂;

up to about 3% ZrO₂;

up to about 1% SnO₂;

up to about 1% Sb₂O₃;

up to about 3% Y₂O₃;

up to about 1% CeO₂;

up to about 1% Eu₂O₃;

up to about 1% Tb₄O₇;

up to about 2% Nb₂O₅; and

up to about 2% Ta₂O₅.

52. A dental product comprising a glass-ceramic comprising:

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.

53. The dental product of claim 52 wherein the glass-ceramic further comprises:

up to about 5% B₂O₃.

up to about 5% Na₂O;

up to about 7% K₂O;

up to about 1.5% F;

up to about 5% ZnO;

up to about 2% MgO;

up to about 7% BaO;

up to about 1% SrO;

up to about 5% Cs₂O;

up to about 7% CaO;

up to about 2% TiO₂;

up to about 3% ZrO₂;

up to about 1% SnO₂;

up to about 1% Sb₂O₃;

up to about 3% Y₂O₃;

up to about 1% CeO₂;

up to about 1% Eu₂O₃;

up to about 1% Tb₄O₇; and

up to about 2% Nb₂O₅.