Lithium silicate glass ceramic

• US 7,867,930 B2
• Filed: 10/17/2008
• Issued: 01/11/2011
• Est. Priority Date: 02/08/2005
• Status: Active Grant

• Current Assignee: Ivoclar Vivadent AG
• Original Assignee: Ivoclar Vivadent AG
• Inventors: Schweiger, Marcel, Holand, Wolfram, Ritzberger, Christian, Apel, Elke, Burke, Harald, Rheinberger, Volker M.
• Primary Examiner(s): Brunsman; David M.
• Assistant Examiner(s): Johnson; Kevin M
• Application Number:
  US12/253,451
• Publication Number:
  US 20090038508A1
• Time in Patent Office: 816 Days
• Field of Search: 501/5, 103/35, 433/228.1
• US Class Current: 501/5
• CPC Class Codes: A61C 13/0004 Computer-assisted sizing or machining of dental prostheses
• CPC Class Codes: A61C 13/0006 Production methods
• CPC Class Codes: A61C 13/0022 Blanks or green, unfinished dental restoration parts
• CPC Class Codes: A61C 13/082 Cosmetic aspects, e.g. inlays; Determination of the colour A61C19/10 takes precedence
• CPC Class Codes: A61C 13/083 Porcelain or ceramic teeth A61C13/081 takes precedence; preparations A61K6/80
• 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: A61C 8/0001 Impression means for implants, e.g. impression coping
• CPC Class Codes: A61C 8/0012 characterised by the material or composition, e.g. ceramics, surface layer, metal alloy use of specific materials A61K6/00
• CPC Class Codes: A61C 8/0048 Connecting the upper structure to the implant, e.g. bridging bars A61C8/0028 takes precedence
• CPC Class Codes: A61K 6/78 Pigments
• CPC Class Codes: A61K 6/804 comprising manganese oxide
• CPC Class Codes: A61K 6/807 comprising magnesium oxide
• CPC Class Codes: A61K 6/818 comprising zirconium oxide
• CPC Class Codes: A61K 6/833 Glass-ceramic composites
• CPC Class Codes: C01B 33/32 Alkali metal silicates C01B33/24 , C01B33/26 take precedence
• 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 10/0045 containing SiO2, Al2O3 and MgO as main constituents
• CPC Class Codes: C03C 10/0054 containing PbO, SnO2, B2O3
• CPC Class Codes: C03C 3/097 : containing phosphorus, niobium or tantalum
• CPC Class Codes: C03C 4/0021 : for dental use
• CPC Class Codes: Y10T 409/303752 : Process
• CPC Class Codes: Y10T 83/04 : Processes

Abstract

Lithium silicate materials are described which can be easily processed by machining to dental products without undue wear of the tools and which subsequently can be converted into lithium silicate products showing high strength.

Claims

1. Process for the preparation of a lithium silicate glass ceramic wherein lithium disilicate is the main crystalline phase comprising the following components:

2. Process according to claim 1, further comprising forming the lithium disilicate glass ceramic into a dental restoration.

3. Process according to claim 1, wherein the first heat treatment in step (b) comprises heating the starting glass to a temperature of 500 to 600°

C. for a period of about 10 minutes to 3 hours.

4. Process according to claim 1, wherein the second heat treatment in step (c) comprises heating the glass product to a second temperature of 680°

to 720°

C.

5. Process according to claim 4, wherein the second temperature comprises from 690°

to 710°

C.

6. Process according to claim 5, wherein the second temperature is about 700°

C.

7. Process according to claim 1, wherein the starting glass of step (a), the glass product of step (b), or the lithium metasilicate glass ceramic of step (c) is shaped to a desired geometry by machining or by hot pressing.

8. Process according to claim 7, wherein the machining is performed by grinding, trimming or milling.

9. Process according to claim 1 wherein the glass ceramic is essentially free of ZnO.

10. Process according to claim 1, wherein the glass ceramic comprises 0 to 2.0 wt. % of Me(II)O.

11. Process according to claim 10, wherein the glass ceramic comprises 0 to 1.5 wt. % of Me(II)O.

12. Process according to claim 1, wherein Me(II)O is selected from at least one of CaO and MgO.

13. Process according to claim 1, wherein the glass ceramic comprises 0.1 to 1.0 wt. % of MgO.

14. Process according to claim 13, wherein the glass ceramic comprises 0.5 to 3.5 wt. % coloring and fluorescent metal oxides.

15. Process according to claim 1, wherein the molar ratio of SiO₂:

Li₂O of the glass ceramic is at least 2.2;

1.

16. Process according to claim 15, wherein the glass ceramic comprises a molar ratio of SiO₂:

Li₂O of at least 2.3;

1.

17. Process according to claim 15, wherein the glass ceramic comprises a molar ratio of SiO₂:

Li₂O in the range of 2.3;

1 to 2.5;

1.

18. Process according to claim 1, wherein the molar ratio of Al₂O₃:

K₂O of the glass ceramic is in the range of 1;

0.5 to 1;

2.0.

19. Process according to claim 18, wherein the molar ratio of Al₂O₃:

K₂O is in the range of 1;

1 to 1;

2.0.

20. Process according to claim 1, wherein the glass ceramic comprises 2.5 to 5.0 wt. % of Al₂O₃.

21. Process according to claim 1, wherein the glass ceramic comprises 70.0 to 73.0 wt. % of SiO₂.

22. Process according to claim 1, wherein the glass ceramic comprises at least one of the following components in an amount of:

23. Process according to claim 1, wherein the glass ceramic further comprises at least one of the following additional components

24. Process according to claim 1, wherein the nucleating agent is at least one of P₂O₅ and compounds of the elements Pt, Ag, Cu and W.

25. Process according to claim 1, further comprising forming the glass ceramic into a blank or a dental restoration.

26. Process according to claim 25, wherein the dental restoration is an inlay, an onlay, a bridge, an abutment, a facing, a veneer, a facet, a crown, a partial crown, a framework or a coping.

27. Process according to claim 1, wherein the glass ceramic comprises 64.0 to 73.0 wt. % SiO₂.

28. Process according to claim 1, wherein the glass ceramic comprises 1.0 to 4.0 wt. % of ZrO₂.

29. Process according to claim 1, wherein the glass ceramic comprises 1.5 to 3.0 wt. % of ZrO₂.