Pre-sintered blank for dental purposes

Patent metadata

Field	Value
Publication number	US-9757217-B2
Application number	US-201314400155-A
Country	US
Kind code	B2
Filing date	May 10, 2013
Priority date	May 11, 2012
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

Pre-sintered blanks based on lithium metasilicate glass ceramic are described which are suitable in particular for the preparation of dental restorations.

First claim

The invention claimed is:

1. Pre-sintered blank for dental purposes based on lithium metasilicate glass ceramic, wherein the blank has a relative density of from 66 to 90% relative to a blank of same composition that has been fully sintered to a lithium disilicate glass ceramic.

2. Pre-sintered blank according to claim 1 , which consists substantially of lithium metasilicate glass ceramic.

3. Pre-sintered blank according to claim 1 , wherein the glass ceramic includes lithium metasilicate as main crystal phase and contains more than 20 vol.-% lithium metasilicate crystals.

4. Pre-sintered blank according to claim 1 , wherein the lithium metasilicate glass ceramic contains at least one of the following components:

Component
wt.-%

SiO 2
50.0 to 80.0

Li 2 O
6.0 to 20.0

Me(I) 2 O
0 to 10.0, in particular 0.1 to 10.0

Me(II)O
0 to 12.0, in particular 0.1 to 12.0

Me(III) 2 O 3
0 to 8.0, in particular 0.1 to 8.0

Me(IV)O 2
0 to 8.0, in particular 0.1 to 8.0

Me(V) 2 O 5
0 to 8.0, in particular 0.1 to 8.0

Me(VI)O 3
0 to 8.0, in particular 0.1 to 8.0

nucleating agent
0 to 8.0, in particular 0.1 to 8.0,

wherein
Me(I) 2 O is selected from Na 2 O, K 2 O, Rb 2 O, Cs 2 O or mixtures thereof,
Me(II)O is selected from CaO, BaO, MgO, SrO, ZnO and mixtures thereof,
Me(III) 2 O 3 is selected from Al 2 O 3 , La 2 O 3 , Bi 2 O 3 , Y 2 O 3 , Yb 2 O 3 and mixtures thereof,
Me(IV)O 2 is selected from ZrO 2 , TiO 2 , SnO 2 , GeO 2 and mixtures thereof,
Me(V) 2 O 5 is selected from Ta 2 O 5 , Nb 2 O 5 and mixtures thereof,
Me(VI)O 3 is selected from WO 3 , MoO 3 and mixtures thereof, and
nucleating agent is selected from P 2 O 5 , metals and mixtures thereof.

5. Pre-sintered blank according to claim 1 , which has at least two areas which differ by their coloration or translucence.

6. Pre-sintered blank according to claim 1 , which has a holder for a processing device.

7. Pre-sintered blank according to claim 1 , which has an interface in the form of a recess, for connection to a dental implant.

8. Pre-sintered blank according to claim 1 , which is obtainable by the process in which
(a) lithium silicate glass in powder or granulate form is pressed to form a glass blank,
(b) the glass blank is heat-treated in order to prepare a pre-sintered blank based on lithium metasilicate glass ceramic, wherein the temperature of the heat treatment
(i) is at least 500° C., and
(ii) lies in a range which extends over at least 30K, and in which the relative density varies by less than 2.5%.

9. Pre-sintered blank according to any claim 1 , which has a relative density which results when
(a) powder of a corresponding starting glass with an average particle size of <50 μm, relative to the number of particles, is uniaxially or isostatically pressed at a pressure of from 20 MPa to 200 MPa and
(b) the obtained glass powder green compact is heat-treated for 5 to 60 min at a temperature which
(i) is at least 500° C., and
(ii) lies in a range which extends over at least 30K and in which the relative density varies by less than 2.5%.

10. Process for the preparation of the blank according to claim 1 , in which
(a) lithium silicate glass in powder or granulate form is pressed to form a glass blank,
(b) the glass blank is heat-treated in order to prepare a pre-sintered blank based on lithium metasilicate glass ceramic, wherein the temperature of the heat treatment
(i) is at least 500° C., and
(ii) lies in a range which extends over at least 30K and in which the relative density varies by less than 2.5%.

11. Process according to claim 10 , in which in step (a) at least two lithium silicate glasses are used which differ in terms of their coloration or translucence.

12. Process for the preparation of dental restorations, in which
(i) the pre-sintered blank based on lithium metasilicate glass ceramic according to claim 1 is shaped by machining to form a precursor of the dental restoration,
(ii) the precursor is substantially dense-sintered in order to produce the dental restoration, and
(iii) optionally the surface of the dental restoration is provided with a finish.

13. Process according to claim 12 , in which the machining is carried out with computer-controlled milling and/or grinding devices.

14. Process according to claim 12 , in which
(a) lithium silicate glass in powder or granulate form is pressed to form a glass blank,
(b) the glass blank is heat-treated in order to prepare a pre-sintered blank based on lithium metasilicate glass ceramic, wherein the temperature of the heat treatment
(i) is at least 500° C., and
(ii) lies in a range which extends over at least 30K and in which the relative density varies by less than 2.5%

in order to obtain the pre-sintered blank based on lithium metasilicate glass ceramic.

15. Process according to claim 12 , in which the dental restorations are selected from crowns, abutments, abutment crowns, inlays, onlays, veneers, shells, bridges and overstructures.

16. Process of using the blank according to claim 1 to prepare dental restorations comprising crowns, abutments, abutment crowns, inlays, onlays, veneers, shells, bridges and overstructures.

17. Pre-sintered blank according to claim 1 , wherein the relative density is from 68 to 88%, relative to a blank of same composition that has been fully sintered to a lithium disilicate glass ceramic.

18. Pre-sintered blank according to claim 1 , wherein the relative density is from 70 to 86%, relative to a blank of same composition that has been fully sintered to a lithium disilicate glass ceramic.

19. Pre-sintered blank according to claim 3 , wherein the glass ceramic contains more than 25 vol.-% lithium metasilicate crystals.

20. Pre-sintered blank according to claim 3 , wherein the glass ceramic contains more than 30 vol.-% lithium metasilicate crystals.

21. Pre-sintered blank according to any claim 9 , wherein the powder of the corresponding starting glass is uniaxially or isostatically pressed at a pressure of from 40 MPa to 120 MPa and the obtained glass powder

Assignees

• Ivoclar Vivadent Ag

Inventors

• Bürke Harald
• Ritzberger Christian
• Schweiger Marcel
• Rheinberger Volker
• Tauch Diana

Classifications

• A61K6/16

  Refractive index · CPC title

• A61K6/833 Primary

  Glass-ceramic composites · CPC title

• A61K6/827

  Leucite · CPC title

• Y10T428/24942

  including components having same physical characteristic in differing degree · CPC title

• C03C3/095

  containing rare earths · CPC title