Process for preparing a glass-ceramic body

Patent metadata

Field	Value
Publication number	US-2016159682-A1
Application number	US-201615042872-A
Country	US
Kind code	A1
Filing date	Feb 12, 2016
Priority date	Apr 20, 2011
Publication date	Jun 9, 2016
Grant date	—

Abstract

A process for preparing glass-ceramic body including the steps of providing a basic glass body and subjecting the basic glass body to a thermal treatment whereby a crystalline phase embedded in a glass matrix is formed. The basic glass body is made of a composition comprising 65 to 72 wt-% SiO 2 , at least 10.1 wt-% Li 2 O and at least 10.1 wt-% Al 2 O 3 based on the total weight of the composition, the proportion of Li 2 O to Al 2 O 3 being from 1:1 to 1.5:1. The thermal treatment involves a nucleation step followed by several crystallization steps at different temperatures, whereby at least two different crystalline phases are formed.

First claim

1 . A process for preparing a glass-ceramic body comprising providing a basic glass body and subjecting the basic glass body to a thermal treatment, wherein:
a crystalline phase embedded in a glass matrix is formed, the basic glass body is made of a composition comprising 65 to 72 wt-% SiO 2 , at least 10.1 wt-% Li 2 O, and at least 10.1 wt-% Al 2 O 3 based on a total weight of the composition, the proportion of Li 2 O to Al 2 O 3 being from 1:1 to 1.5:1, and the thermal treatment comprises a nucleation step followed by a first crystallization step at a first temperature range and a second crystallization step at a second temperature range different from the first temperature range to form at least two different crystalline phases.

2 . The process for preparing a glass-ceramic body according to claim 1 , wherein a first region of the glass body is subjected to the first crystallization step and a second region of the glass body different from the first region is subjected to the second crystallization step such that a proportion of the first crystalline phase is higher in the first region than in the second region, and a proportion of the second crystalline phase is higher in the second region than in the first region.

3 . The process according to claim 2 , wherein the first region and the second region are heated to the first temperature range and the second temperature range, respectively, by means of laser irradiation, electromagnetic radiation, and/or susceptors.

4 . The process according to claim 1 , wherein the first temperature range is from 620 to 820° C., and the second temperature range starts from 825° C.

5 . A glass composition comprising 65 to 72 wt-% SiO 2 , at least 10.1 wt-% Li 2 O, and at least 10.1 wt-% Al 2 O 3 based on a total weight of the composition, the proportion of Li 2 O to Al 2 O 3 being from 1:1 to 1.5:1.

6 . The glass composition according to claim 5 , comprising at most 15 wt-% of Li 2 O and/or at most 15 wt-% of Al 2 O 3 .

7 . The glass composition according to claim 5 , further comprising 0 to 2 wt-% K 2 O, 1 to 4 wt-% Na 2 O, 0 to 1.5 wt-% CaO, 0 to 1.0 wt-% MgO, 0 to 1.5 wt-% B 2 O 3 , 0 to 1.5 wt-% CeO 2 , 1 to 5 wt-% P 2 O 5 , 0 to 3 wt-% CaF 2 , 0 to 2.0 wt-% AlF 3 , 0 to 1.0 wt-% Ag, 0 to 5 wt-% ZrO 2 , and 0 to 4 wt-% TiO 2 based on the total weight of the composition.

8 . The glass composition according to claim 5 , further comprising 0 to 2 wt-% K 2 O, at most 4 wt-% Na 2 O, 0 to 1.5 wt-% CaO, 0 to 1.5 wt-% CeO 2 , 1 to 5 wt-% P 2 O 5 , 0 to 0.5 wt-% V 2 O 5 , 0 to 1 wt-% Ag, and 0 to 1 wt-% ZrO 2 , the composition being devoid of TiO 2 , Cu 2 O, BaO, Sb 2 O 3 , Nb 2 O 5 , MgO, La 2 O 3 , and SnO 2 .

9 . The glass composition according to claim 5 , essentially consisting of 0 to 2 wt-% K 2 O, at most 4 wt-% Na 2 O, 0 to 1.5 wt-% CaO, 0 to 1.5 wt-% CeO 2 , 1 to 5 wt-% P 2 O 5 , 0 to 0.05 wt-% V 2 O 5 , 0 to 1 wt-% Ag, and 0 to 1 wt-% ZrO 2 besides SiO 2 , Li 2 O, and Al 2 O 3 .

10 . A glass-ceramic body comprising at least two crystalline phases selected from the group consisting of Li 2 SiO 3 , Li 2 Si 2 O 5 , LiAlSi 2 O 6 , LiAlSiO 4 , LiAlSi 3 O 8 , LiAlSi 4 O 10 , and Li 3 PO 4 .

11 . The glass-ceramic body according to claim 10 , comprising:
a) a first crystalline phase of Li 2 Si 2 O 5 , and b) a second crystalline phase selected from the group consisting of LiAlSi 2 O 6 , LiAlSiO 4 , LiAlSi 3 O 8 , and LiAlSi 4 O 10 .

12 . The glass-ceramic body according to claim 11 , further comprising a first region and a second region different from the first region, wherein a proportion of the first crystalline phase is higher in the first region than in the second region, and a proportion of the second crystalline phase is higher in the second region than in the first region.

13 . The glass-ceramic body according to claim 12 , wherein the first crystalline phase and the second crystalline phase change gradually from region to region.

14 . The glass-ceramic body according to claim 12 , the glass-ceramic body being in the form of a dental restoration having an enamel area and a dentin area corresponding to the respective areas of a natural tooth, with the first region being arranged in the enamel area and the second region being arranged in the dentin area.

15 . A method of forming a dental restoration comprising forming the dental restoration from the glass-ceramic body according to claim 10 .

16 . The glass-ceramic body according to claim 13 , the glass-ceramic body being in the form of a dental restoration having an enamel area and a dentin area corresponding to the respective areas of a natural tooth, with the first region being arranged in the enamel area and the second region being arranged in the dentin area.

17 . The process according to claim 1 , wherein the nucleation step is carried out at a temperature of 500° C. to 570° C.

Assignees

• Straumann Holding Ag

Inventors

• Borczuch-Laczka Maria
• Cholewa-Kowalska Katharzyna
• Laczka Karolina

Classifications

• A61K6/833

  Glass-ceramic composites · CPC title

• A61K6/824

  comprising transition metal oxides · CPC title

• A61K6/816

  comprising titanium oxide · CPC title

• A61K6/822

  comprising rare earth metal oxides · CPC title

• A61K6/818

  comprising zirconium oxide · CPC title