Lithium silicate glass ceramic and glass with trivalent metal oxide

Patent metadata

Field	Value
Publication number	US-10321980-B2
Application number	US-201615193202-A
Country	US
Kind code	B2
Filing date	Jun 27, 2016
Priority date	Oct 14, 2011
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

Lithium silicate glass ceramics and glasses comprising specific oxides of trivalent 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 for the preparation of dental restorations for use in the oral cavity from said glass ceramic or for the coating of dental restorations for use in the oral cavity with said glass ceramic, wherein said glass ceramic comprises a trivalent metal oxide selected from Y 2 O 3 , La 2 O 3 , Yb 2 O 3 , Bi 2 O 3 and mixtures thereof, wherein the glass ceramic is substantially free from K 2 O and Na 2 O.

2. Glass ceramic according to claim 1 , which comprises less than 0.1 wt.-% MgO and ZnO.

3. Glass ceramic according to claim 1 , wherein the trivalent metal oxide is selected from Y 2 O 3 , Yb 2 O 3 , Bi 2 O 3 and mixtures thereof.

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

5. Glass ceramic according to claim 1 , which has lithium metasilicate as main crystal phase.

6. Glass ceramic according to claim 1 , which has lithium disilicate as main crystal phase.

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

8. Glass ceramic according to claim 1 , which comprises 13.0 to 21.0 wt.-% Li 2 O.

9. Glass ceramic according to claim 1 , which comprises 0 to 8.0 wt.-% P 2 O 3 .

10. 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.

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

12. 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.

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

Component
wt.-%

SiO 2
68.0 to 78.0

Li 2 O
13.0 to 20.0

trivalent metal oxide
2.0 to 6.0

and mixtures thereof

Al 2 O 3
  0 to 6.0

Rb 2 O and/or Cs 2 O
  0 to 5.0

P 2 O 5
   0 to 4.5.

14. Lithium silicate glass ceramic according to claim 1 , which has lithium disilicate as main crystal phase and a fracture toughness, measured as K IC value, of at least 1.8 MPa·m 0.5 .

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. Dental lithium silicate glass with nuclei which are suitable for forming lithium metasilicate and/or lithium disilicate crystals, wherein the glass comprises the components of the glass ceramic according to claim 1 .

17. Glass according to claim 16 , wherein the glass ceramic is present in the form of a powder, a granular material, a blank or a dental restoration.

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

19. Process for the preparation of the glass according to claim 17 , wherein a starting glass is subjected to at least one heat treatment in the range of from 450 to 950° C.

20. Process for the preparation of a lithium silicate glass ceramic which comprises a trivalent metal oxide selected from Y 2 O 3 , La 2 O 3 , Yb 2 O 3 , Bi 2 O 3 and mixtures thereof, wherein the glass ceramic is substantially free from K 2 O and Na 2 O, wherein
(a) a starting glass which comprises the components of the glass ceramic is subjected to a heat treatment for a period of 10 min to 30 min at a temperature of from 480 to 510° C. in order to form a glass with nuclei which are suitable for forming lithium disilicate crystals, and
(b) the glass with nuclei is subjected to a heat treatment at a temperature of from 630 to 720° C. for a period of 10 min to 60 min in order to form a glass ceramic with lithium disilicate as main crystal phase.

21. Process of using a lithium silicate glass ceramic, a starting glass or a glass with nuclei which are suitable for forming lithium metasilicate and/or lithium disilicate crystals, wherein the glass ceramic and the glass comprise a trivalent metal oxide selected from Y 2 O 3 , La 2 O 3 , Yb 2 O 3 , Bi 2 O 3 and mixtures thereof and is substantially free from K 2 O and Na 2 O, as a dental material comprising preparing a dental restoration for use in the oral cavity from said glass ceramic or coating a dental restoration for use in the oral cavity with said glass ceramic.

22. Process according to claim 21 , wherein preparing the dental restoration comprises shaping by pressing or machining the glass ceramic or the glass to the dental restoration.

23. Process according to claim 20 , wherein the heat treatment of step (b) is for a period of from 10 min to 30 min.

Assignees

• Ivoclar Vivadent Ag

Inventors

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

Classifications

• 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

• A61C13/0022

  Blanks or green, unfinished dental restoration parts · CPC title

• C03B19/063

  by hot-pressing powders · CPC title

• C03C23/007

  by thermal treatment · CPC title

• C03C19/00

  Surface treatment of glass, not in the form of fibres or filaments, by mechanical means (sand-blasting, grinding, or polishing glass B24) · CPC title