Pre-sintered blank for dental purposes

Patent metadata

Field	Value
Publication number	US-2017340420-A1
Application number	US-201715677306-A
Country	US
Kind code	A1
Filing date	Aug 15, 2017
Priority date	May 11, 2012
Publication date	Nov 30, 2017
Grant date	—

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

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 and wherein the pre-sintered blank has layers which differ in color or translucence.

2 . 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.

3 . 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.

4 . Pre-sintered blank according to claim 1 , wherein the layers comprise at least three layers.

5 . Pre-sintered blank according to claim 1 , wherein the layers comprise up to ten layers.

6 . Pre-sintered blank according to claim 1 , wherein the layers have a color gradient to ensure continuous color transition.

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

8 . 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.

9 . Pre-sintered blank according to claim 8 , wherein the glass ceramic contains more than 25 vol.-% lithium metasilicate crystals.

10 . Pre-sintered blank according to claim 8 , wherein the glass ceramic contains more than 30 vol.-% lithium metasilicate

11 . 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

Me(II)O
 0 to 12.0

Me(III) 2 O 3
0 to 8.0

Me(IV)O 2
0 to 8.0

Me(V) 2 O 5
0 to 8.0

Me(VI)O 3
0 to 8.0

nucleating agent
0 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.

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

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

14 . Pre-sintered blank according to claim 1 , which is obtainable by the process of arranging differently colored or differently translucent powders or granulates in layers on top of one another in a compression mold.

15 . Pre-sintered blank according to 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%.

16 . Pre-sintered blank according to claim 15 , 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 green compact is heat-treated for 10 to 40 min at a temperature which is at least 540° C., and lies in a range which extends over at least 50K and in which the relative density varies by less than 2.0%

17 . Pre-sintered blank according to claim 15 , wherein the powder of the corresponding starting glass is uniaxially or isostatically pressed at a pressure of from 50 MPa to 100 MPa and the obtained glass powder green compact is heat-treated for 15 to 30 min at a temperature which is at least 580° C., and lies in a range which extends over at least 70K and in which the relative density varies by less than 1.5%.

18 . Process for the preparation of the pre-sintered blank according to claim 1 , in which
(a) layers of differently colored or differently translucent lithium silicate glass powders or granulates are 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%.

19 . Process for the preparation of the blank according to 18 , wherein the temperature of the heat treatment is at least 540° C., and lies in a range which extends over at least 50K and in which the relative density varies by less than 2.0%.

20 . Process for the preparation of the blank according to 18 , wherein the temperature of the heat treatment is at least 580° C., and lies in a range which extends over at least 70K, and in which the relative density varies by less than 1.5%.

21 . 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.

22 . Process according to claim 21 , in which the machining is carried out with computer-controlled milling and/or grinding devices.

23 . Process according to claim 21 , in which the denta

Assignees

• Ivoclar Vivadent Ag

Inventors

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

Classifications

• A61K6/833 Primary

  Glass-ceramic composites · CPC title

• A61K6/827

  Leucite · CPC title

• A61K6/16

  Refractive index · CPC title

• C03C3/097

  containing phosphorus, niobium or tantalum · CPC title

• C03C3/085

  containing an oxide of a divalent metal · CPC title