Lithium silicate glass ceramic and lithium silicate glass comprising a divalent metal oxide

Patent metadata

Field	Value
Publication number	US-9232989-B2
Application number	US-201214001182-A
Country	US
Kind code	B2
Filing date	Oct 11, 2012
Priority date	Oct 14, 2011
Publication date	Jan 12, 2016
Grant date	Jan 12, 2016

Abstract

Lithium silicate glass ceramics and glasses containing specific oxides of divalent elements are described which crystallize at low temperatures and are suitable in particular as dental materials.

First claim

The invention claimed is:

1. Lithium silicate glass ceramic which comprises a divalent metal oxide selected from MgO, CaO, SrO, BaO, ZnO and mixtures thereof and comprises at least 12.1 wt.-% Li 2 O, 67.0 to 85.0 wt.-% SiO 2 , 2.0 to 9.0 wt.-% P 2 O 5 and less than 1.0 wt. % K 2 O, and which has lithium metasilicate as a main crystal phase.

2. Glass ceramic according to claim 1 , wherein lithium silicate glass ceramic is excluded which comprises at least 6.1 wt.-% ZrO 2 .

3. Glass ceramic according to claim 1 , wherein lithium silicate glass ceramic is excluded which comprises at least 8.5 wt.-% transition metal oxide selected from the group consisting of oxides of yttrium, oxides of transition metals with an atomic number from 41 to 79 and mixtures of these oxides.

4. Glass ceramic according to claim 1 , which comprises less than 1.0 wt.-% K 2 O, Na 2 O and mixtures thereof.

5. Glass ceramic according to claim 1 , which comprises in addition to Li 2 O less than 1.0 wt.-% further alkali metal oxide and mixtures thereof.

6. Glass ceramic according to claim 1 , which comprises less than 0.1 wt.-% La 2 O 3 .

7. Glass ceramic according to claim 1 , which comprises the divalent metal oxide or mixtures thereof in an amount of from 0.1 to 15 wt.-%.

8. Lithium silicate glass ceramic which comprises a divalent metal oxide selected from MgO, CaO, SrO, BaO, ZnO and mixtures thereof and comprises at least 12.1 wt.-% Li 2 O, 67.0 to 85.0 wt.-% SiO 2 , 2.0 to 9.0 wt.-% P 2 O 5 and less than 1.0 wt. % K 2 O, wherein the divalent metal oxide is SrO.

9. Glass ceramic according to claim 1 , which comprises 55.0 to 85.0 wt.-% SiO 2 .

10. Glass ceramic according to claim 1 , which comprises 12.5 to 20.0 wt.-% Li 2 O.

11. Glass ceramic according to claim 1 , which comprises at least one of the following components:

Component
wt.-%

SiO 2
67.5 to 79.0

Li 2 O
12.5 to 20.0

divalent metal
 2.0 to 12.0

oxide or mixtures

P 2 O 5
  0 to 7.0

Al 2 O 3
   0 to 6.0.

12. Lithium silicate glass ceramic according to claim 1 , which comprises SiO 2 and Li 2 O in a molar ratio of from 1.7 to 3.1.

13. Lithium silicate glass ceramic according to claim 1 , which comprises less than 5.0 wt.-% BaO.

14. Lithium silicate glass with nuclei which are suitable for forming lithium metasilicate, wherein the glass comprises the components of the glass ceramic according to claim 1 .

15. Glass ceramic according to claim 1 , wherein the glass ceramic is present in the form of a powder, a granular material, a blank or a dental restoration.

16. Process for the preparation of a lithium silicate glass ceramic which comprises a divalent metal oxide selected from MgO, CaO, SrO, BaO, ZnO and mixtures thereof and comprises at least 12.1 wt.-% Li 2 O, 67.0 to 85.0 wt.-% SiO 2 , 2.0 to 9.0 wt.-% P 2 O 5 and less than 1.0 wt. % K 2 O, wherein a starting glass is subjected to at least one heat treatment in the range of from 450 to 950° C.

17. Process according to claim 16 , wherein
(a) the starting glass is subjected to a heat treatment at a temperature of from 470 to 560° C. in order to form the glass with nuclei, and
(b) the glass with nuclei is subjected to a heat treatment at a temperature of from 600 to 750° C. in order to form the glass ceramic with lithium disilicate as main crystal phase.

18. A method of using the glass ceramic according to claim 1 as dental material.

19. A method of using a lithium silicate glass ceramic which comprises a divalent metal oxide selected from MgO, CaO, SrO, BaO, ZnO and mixtures thereof and comprises at least 12.1 wt.-% Li 2 O, 67.0 to 85.0 wt.-% SiO 2 , 2.0 to 9.0 wt.-% P 2 O 5 and less than 1.0 wt. % K 2 O, wherein the glass ceramic is shaped by pressing or machining to a desired dental restoration.

20. Glass ceramic according to claim 1 , wherein the lithium metasilicate as a main crystal phase has more than 5 vol.-% lithium metasilicate crystals.

21. Lithium silicate glass ceramic which comprises a divalent metal oxide selected from MgO, CaO, SrO, BaO, ZnO and mixtures thereof and comprises at least 12.1 wt.-% Li 2 O, 67.0 to 85.0 wt.-% SiO 2 , 2.0 to 9.0 wt.-% P 2 O 5 and less than 1.0 wt. % K 2 O, which has lithium disilicate as a main crystal phase and has more than 10 vol.-% lithium disilicate crystals.

Assignees

• Ivoclar Vivadent Ag

Inventors

• Ritzberger Christian
• Apel Elke
• Höland Wolfram
• Rheinberger Volker

Classifications

• A61K6/802

  comprising ceramics · CPC title

• A61K6/80

  Preparations for artificial teeth, for filling teeth or for capping teeth · CPC title

• C03C10/0027

  containing SiO2, Al2O3, Li2O as main constituents · CPC title

• Y10T29/49567

  Dental appliance making · CPC title

• C03C10/00

  Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition · CPC title