Claims
- 1. A process for making a lithium disilicate glass ceramic comprising the following components:ComponentWt. %SiO257.0 to 80.0Al2O3 0 to 5.0La2O30.1 to 6.0MgO 0 to 5.0ZnO 0 to 8.0K2O 0 to 13.5Li2O11.0 to 19.0P2O5 0 to 11.0Color components 0 to 8.0Additional components 0 to 6.0whereinAl2O3+La2O3 equals 0.1 to 7.0 wt. % and MgO+ZnO equals 0.1 to 9.0 wt. % comprising: fusing starting glass components to form a glass melt; forming glass granules from the glass melt; comminuting the glass granules to form a powder; compacting the powder to form a glass blank; and subjecting the glass blank to a first heat treatment step to produce a glass ceramic blank.
- 2. The process according to claim 1, wherein the fusing step occurs at a temperature of 1200° to 1650° C.
- 3. The process according to claim 1, wherein the forming step comprises pouring the glass melt into water.
- 4. The process according to claim 2, wherein the powder has an average particle size of 1 to 100 μm, based on the number of particles.
- 5. The process according to claim 1, wherein compacting step produces a glass blank which is heterogeneous.
- 6. The process according to claim 3, wherein the first heat treatment step comprises heating the glass blank under vacuum at a temperature of from 400° to 1100° C.
- 7. The process according to claim 6, wherein the first heat treatment step results in surface crystallization of the glass blank.
- 8. The process according to claim 6, wherein the first heat treatment step occurs in more than one step.
- 9. The process according to claim 1, further comprising adding coloring bodies after the comminuting step and before the compacting step.
- 10. The process according to claim 1, further comprising subjecting the glass-ceramic blank to a second heat treatment step to produce a dental product.
- 11. The process according to claim 10, wherein the second heat treatment occurs at a temperature of 700° to 1200° C. and a pressure of 2 to 10 bar.
- 12. The process according to claim 10, further comprising machining the glass-ceramic blank to produce a dental product.
- 13. A process according to claim 12, further comprising providing the dental product with a coating.
- 14. The process according to claim 13, wherein the coating is a ceramic, a sintered ceramic, a glass ceramic, a glass, a glaze, or a composite.
- 15. A process according to claim 14, wherein the coating has a sintering temperature of 650 to 950° C. and a coefficient of linear expansion which is lower than that of the dental product to be coated.
- 16. A process according to claim 14, wherein the coating has a coefficient of linear expansion which deviates by no more than ±3.0×10−6 K−1 from that of the dental product.
- 17. The process according to claim 1, wherein the lithium disilicate glass ceramic has a viscosity of 105 to 106 Pa.s at a temperature of 700° to 1200° C.
- 18. The process according to claim 1, wherein the lithium disilicate glass ceramic is capable of flow in a controlled manner when pressed in a mold at a temperature of 700° to 1200° C.
- 19. The process according to claim 1, wherein the lithium disilicate glass ceramic is produced from a glass having a heterogeneous structure such that surface crystallization takes place during formation of the glass ceramic.
- 20. The process according to claim 1, wherein the color components are formed from glass-colored oxides, coloring bodies, or mixtures thereof in the following quantities:glass-coloring oxides0 to 5.0 wt. % andcoloring bodies0 to 5.0 wt. %.
- 21. The process according to claim 1, wherein the lithium disilicate glass ceramic essentially consists of the components specified.
- 22. The process according to claim 1, wherein TiO2, CeO2, Fe2O3, or mixtures thereof are present in the lithium disilicate glass ceramic as glass-coloring oxides.
- 23. The process according to claim 1, wherein the lithium disilicate glass ceramic contains doped spinels, doped ZrO2, or mixtures thereof as coloring bodies.
- 24. The process according to claim 1, wherein the additional components are B2O3, F, Na2O, ZrO2, BaO, SrO, or mixtures thereof.
- 25. The process according to claim 1, wherein the quantities of the components of the lithium disilicate glass ceramic, independently of one another, are as follows:ComponentWt. %SiO257.0 to 75.0Al2O3 0 to 2.5La2O30.1 to 4.0MgO0.1 to 4.0ZnO 0 to 6.0K2O 0 to 9.0Li2O13.0 to 19.0P2O5 0 to 8.0Color components0.05 to 6.0 Additional components 0 to 3.0.
- 26. The process according to claim 1, wherein the lithium disilicate glass ceramic composition includes:ComponentWt. %ZnO.1 to 5.0K2O.5 to 7.0P2O5 .5 to 8.0.
- 27. The process according to claim 1, wherein the first heat treatment results in surface crystalization of the glass blank.
- 28. The process according to claim 27, wherein the first heat treatment results in volume crystalization of the glass blank.
- 29. The process according to claim 1, further comprising computer-controlled milling of the glass ceramic blank to produce a dental product.
Priority Claims (2)
Number |
Date |
Country |
Kind |
196 35 940 |
Sep 1996 |
DE |
|
196 47 739 |
Nov 1996 |
DE |
|
Parent Case Info
This application is a divisional of U. S. patent application Ser. No. 09/379,450 filed Aug. 23, 1999, now U.S. Pat. No. 6,342,458, which is a divisional of U.S. patent application Ser. No. 08/924,232 filed Sep. 5, 1997, now U.S. Pat. No. 5,968,856, which claims the benefit of U.S. Provisional Patent Application Serial No. 60/040,827, filed Mar. 20, 1997.
US Referenced Citations (20)
Foreign Referenced Citations (5)
Number |
Date |
Country |
0 690 031 |
Jan 1996 |
EP |
1 424 398 |
Feb 1976 |
GB |
55-126546 |
Sep 1980 |
JP |
07-250848 |
Oct 1995 |
JP |
08-040744 |
Feb 1996 |
JP |
Provisional Applications (1)
|
Number |
Date |
Country |
|
60/040827 |
Mar 1997 |
US |