LITHIUM DISILICATE GLASS-CERAMIC, METHOD FOR PRODUCTION THEREOF AND USE THEREOF

• US 20120309607A1
• Filed: 12/23/2010
• Published: 12/06/2012
• Est. Priority Date: 12/23/2009
• Status: Active Grant

• Current Assignee: Degudent GmbH, Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V., Vita Zahnfabrik H. Rauter GMBH & Co.. KG (Rauter Beteiligungsgesellschaft mbH)
• Original Assignee: Degudent GmbH, Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V., Vita Zahnfabrik H. Rauter GMBH & Co.. KG (Rauter Beteiligungsgesellschaft mbH)
• Inventors: Durschang, Bernhard, Thiel, Norbert, Bibus, Joachim, Vollmann, Markus, Schusser, Udo, Probst, Jorn
• Granted Patent: US 8,956,987 B2
• Time in Patent Office: Days
• US Class Current: 501/59
• CPC Class Codes: A61C 13/0006 Production methods
• CPC Class Codes: A61C 13/01 Palates or other bases or supports for the artificial teeth; Making same
• CPC Class Codes: A61C 13/083 Porcelain or ceramic teeth A61C13/081 takes precedence; preparations A61K6/80
• CPC Class Codes: A61C 5/35 Pins; Mounting tools or dispensers therefor
• CPC Class Codes: A61C 5/70 Tooth crowns; Making thereof
• CPC Class Codes: A61C 5/77 Methods or devices for making crowns
• CPC Class Codes: A61K 6/78 Pigments
• CPC Class Codes: A61K 6/816 comprising titanium oxide
• CPC Class Codes: A61K 6/818 comprising zirconium oxide
• CPC Class Codes: A61K 6/82 comprising hafnium 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 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
• CPC Class Codes: G01J 1/44 Electric circuits for command of an exposure part G03B7/02

Abstract

The invention relates to glass-ceramics based on the lithium disilicate system which can be mechanically machined easily in an intermediate step of crystallisation and, after complete crystallisation, represent a very strong, highly-translucent and chemically-stable glass-ceramic. Likewise, the invention relates to a method for the production of these glass-ceramics. The glass-ceramics according to the invention are used as dental material.

Claims

1. A lithium disilicate glass-ceramic having the following composition:

55 to 70% by weight of SiO₂,

10 to 15% by weight of Li0₂,

10 to 20% by weight of the stabiliser selected from the group consisting of ZrO₂, HfO₂ and mixtures thereof,

0.1 to 5% by weight of K₂O,

0.1 to 5% by weight of Al₂O₃,

0 to 10% by weight of additives selected from the group consisting of boron oxide, phosphorus oxide, fluorine, sodium oxide, barium oxide, strontium oxide, magnesium oxide, zinc oxide, calcium oxide, yttrium oxide, titanium oxide, niobium oxide, tantalum oxide, lanthanum oxide and mixtures thereof, and

0 to 10% by weight of colourants.

2. The lithium disilicate glass-ceramic according to claim 1, wherein the colourants are glass-colouring oxides and/or pigments.

3. The lithium disilicate glass-ceramic according to claim 1, wherein the glass-colouring oxides are selected from the group of the oxides of iron, titanium, cerium, copper, chromium, cobalt, nickel, manganese, selenium, silver, indium, gold, and rare earth metals.

4. The lithium disilicate glass-ceramic according to claim 1, wherein the pigments are doped spinels.

5. The lithium disilicate glass-ceramic according to claim 1 having the following composition:

58 to 64% by weight of SiO₂,

11 to 13% by weight of LiO₂,

10 to 15% by weight of the stabiliser selected from the group consisting of ZrO₂, HfO₂ and mixtures thereof,

2 to 5% by weight of K₂O,

2 to 5% of Al₂O₃,

2 to 5% of P₂O₅ and also

0 to 5% by weight of additives selected from the group consisting of boron oxide, phosphorus oxide, fluorine, sodium oxide, barium oxide, strontium oxide, magnesium oxide, zinc oxide, calcium oxide, yttrium oxide, titanium oxide, niobium oxide, tantalum oxide, lanthanum oxide and mixtures thereof, and

0 to 10% by weight of colourants.

6. A method for the production of a lithium disilicate glass-ceramic according to claim 1, in which

a) an initial glass is produced which comprises the components of the glass-ceramic,

b) the initial glass is subjected to a first heat treatment in order to produce a glass-ceramic which has lithium metasilicate as main crystal phase,

c) the glass-ceramic of b) is subjected to a second heat treatment in which the lithium metasilicate is converted with SiO₂ from the glass phase into lithium disilicate and subsequently lithium disilicate is present as main crystal phase.

7. The method according to claim 6, wherein the first heat treatment is effected at a temperature of 620°

C. to 800°

C. over a period of time of 1 to 200 min.

8. The method according to claim 7,

wherein the second heat treatment is effected at a temperature of 800°

C. to 1,040°

C. over a period of time of 5 to 200 min.

11. The lithium disilicate glass-ceramic according to claim 3, wherein the rare earth metals are selected from the group consisting of neodymium, praseodymium, samarium and europium.

12. The method according to claim 7, wherein the first heat treatment is effected at a temperature of 650°

C. to 750°

C. over a period of time of 10 to 60 min.

13. The method according to claim 8, wherein the second heat treatment is effected at a temperature of 800°

C. to 870°

C. over a period of time of 5 to 30 min.

14. A dental material comprising the lithium disilicate glass-ceramic according to claim 1.

15. A shaped dental product comprising the lithium disilicate glass-ceramic according to claim 1.

16. The shaped dental product according claim 15, which is an inlay, an onlay, a bridge, a pin construction, a veneer, or a crown.

9-10. -10. (canceled)