Lithium Silicate Glass Ceramic And Glass With Divalent Metal Oxide

Patent metadata

Field	Value
Publication number	US-2017362118-A1
Application number	US-201715695285-A
Country	US
Kind code	A1
Filing date	Sep 5, 2017
Priority date	Oct 14, 2011
Publication date	Dec 21, 2017
Grant date	—

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

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 and less than 1.0 wt.-% K 2 O and which comprises lithium metasilicate as a main crystal phase.

2 . Glass ceramic according to claim 1 , which comprises more than 5 vol.-% lithium metasilicate crystals.

3 . Glass ceramic according to claim 1 , which comprises more than 10 vol.-% lithium metasilicate crystals.

4 . Glass ceramic according to claim 1 , which comprises more than 15 vol.-% lithium metasilicate crystals.

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

6 . Glass ceramic according to claim 1 , which comprises less than 1.0 wt.-% further alkali metal oxide.

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

8 . 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.-%.

9 . Glass ceramic according to claim 1 , wherein the divalent metal oxide is SrO.

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

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

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

13 . Glass ceramic according to claim 1 , which comprises 0 to 10.0 wt.-% P 2 O 5 .

14 . 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 oxide
 2.0 to 12.0

or mixtures

P 2 O 5
  0 to 7.0

Al 2 O 3
   0 to 6.0.

15 . Lithium silicate glass ceramic according to claim 1 , wherein the molar ratio between SiO 2 and Li 2 O is in the range of from 1.7 to 3.1.

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

17 . 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.

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

19 . 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.

20 . Process for the preparation of the glass ceramic according to claim 1 , wherein a starting glass or a glass with nuclei is subjected to at least one heat treatment in the range of from 450 to 950° C.

21 . 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 and less than 1.0 wt.-% K 2 O, wherein
(a) a 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.

22 . Process according to claim 21 , wherein the heat treatment in step (b) is carried out for a period of from 10 min to 120 min.

23 . A process 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 and less than 1.0 wt.-% K 2 O as dental material, wherein the glass ceramic is shaped by pressing or machining to a desired dental restoration.

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

• A61L27/10 Primary

  Ceramics or glasses · 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

• C03C10/0009 Primary

  containing silica as main constituent · CPC title