Method For The Preparation Of Glasses And Glass Ceramics With SiO2 As Main Crystal Phase

Patent metadata

Field	Value
Publication number	US-2018282204-A1
Application number	US-201615524420-A
Country	US
Kind code	A1
Filing date	Oct 28, 2016
Priority date	Nov 11, 2015
Publication date	Oct 4, 2018
Grant date	—

Abstract

The invention also relates to a glass ceramic and a glass which can be obtained using the method according to the invention, the use thereof as dental material and in particular for the preparation of dental restorations, as well as a glass-forming composition which is suitable for use in the method according to the invention.

First claim

1 . Method for the preparation of a glass ceramic with SiO 2 as main crystal phase or a glass which comprises nuclei for the crystallization of SiO 2 , which comprises a step in which a melt of a starting glass which comprises cerium ions is exposed to reducing conditions.

2 . Method according to claim 1 , in which the melt of the starting glass is reacted with at least one reducing agent.

3 . Method according to claim 2 , in which the melt of the starting glass is formed from a glass-forming composition which comprises SiO 2 , Li 2 O, a cerium compound and at least one reducing agent.

4 . Method according to claim 2 , in which the at least one reducing agent is a compound which comprises at least one oxidizable carbon atom.

5 . Method according to claim 4 , in which the at least one reducing agent is an acetylacetonate.

6 . Method according to claim 2 , in which the at least one reducing agent is a reducing gas.

7 . Method according to claim 1 , in which the starting glass comprises 0.1 to 7.0 wt.-% cerium ions, calculated as CeO 2 .

8 . Method according to claim 1 , in which the starting glass further comprises terbium ions.

9 . Method according to claim 1 , in which the starting glass comprises 0 to 11.0 wt.-% alkaline earth metal oxide.

10 . Method according to claim 1 , in which the starting glass comprises at least one of the following components in the given quantities:

Component
wt.-%

SiO 2
58.0 to 92.0

Li 2 O
2.0 to 10.0

CeO 2
0.1 to 7.0

Tb 4 O 7
0 to 2.0

Me I 2 O
0 to 13.0

Me II O
0 to 11.0

Me III 2 O 3
0 to 10.0

Me IV O 2
0 to 21.0

P 2 O 5
0 to 7.0

Me V 2 O 5
0 to 6.0

Me VI O 3
0 to 6.0

fluorine
0 to 5.0,

wherein
Me I 2 O is selected from Na 2 O, K 2 O, Rb 2 O and/or Cs 2 O,
Me II O is selected from MgO, CaO, SrO and/or ZnO,
Me III 2 O 3 is selected from Al 2 O 3 , B 2 O 3 , Y 2 O 3 , La 2 O 3 , Ga 2 O 3 and/or In 2 O 3 ,
Me IV O 2 is selected from ZrO 2 , GeO 2 , TiO 2 and/or SnO 2 ,
Me V 2 O 5 is selected from V 2 O 5 , Ta 2 O 5 and/or Nb 2 O 5 and
Me VI O 3 is selected from WO 3 and/or MoO 3 .

11 . Method according to claim 1 for the preparation of a glass with nuclei which are suitable for forming low quartz, cristobalite or a mixture thereof.

12 . Method according to claim 1 for the preparation of a glass ceramic which has low quartz, cristobalite or a mixture thereof as main crystal phase.

13 . Method according to claim 1 for the preparation of a glass ceramic which comprises 5.0 to 50.0 wt.-% SiO 2 as crystal phase.

14 . Method according to claim 1 , in which the starting glass is subjected to at least one heat treatment in the range of from 700° to 950° C.

15 . Method according to claim 1 , in which the glass ceramic or the glass are present in the form of a powder, a blank or a dental restoration.

16 . Glass ceramic with SiO 2 as main crystal phase or glass which comprises nuclei for the crystallization of SiO 2 , which is obtainable using the method according to claim 1 .

17 . Glass ceramic with SiO 2 as main crystal phase or glass which comprises nuclei for the crystallization of SiO 2 , which have a fluorescence intensity at 420 nm and/or 541 nm which is at least 1.5 times the corresponding fluorescence intensity of a reference sample,
wherein the reference sample is obtainable by melting a starting glass with the composition: 74.3 wt.-% SiO 2 , 7.7 wt.-% Li 2 O, 3.4 wt.-% K 2 O, 1.8 wt.-% MgO, 3.3 wt.-% CaO, 4.0 wt.-% Al 2 O 3 , 3.6 wt.-% P 2 O 5 , 1.5 wt.-% CeO 2 and 0.4 wt.-% Tb 4 O 7 on a scale of 200 g from suitable raw materials in a platinum-rhodium crucible at 1650° C. for 1 h, pouring 30 g of the glass melt into a pre-heated mould in order to produce a glass block, and converting the glass block into a glass ceramic by successive temperature treatments at 530° C. for 20 min and 800° C. for 30 min, wherein the heating rates between the temperature treatments are 30 K/min in each case.

18 . (canceled)

19 . Method of using the glass ceramic or the glass according to claim 16 as dental material.

20 . Method according to claim 19 , in which the glass ceramic or the glass are shaped by pressing or machining to form a desired dental restoration.

21 . Method according to claim 4 , in which the at least one reducing agent is selected from the group consisting of organic salts, carbohydrates and cereal flours.

22 . Method according to claim 6 , in which the at least one reducing agent comprises hydrogen or hydrogen and nitrogen.

23 . Method according to claim 7 , in which the starting glass comprises 1.0 to 4.0 wt.-% cerium ions, calculated as CeO 2 .

24 . Method according to claim 8 , in which the starting glass comprises 0.05 to 2.0 wt.-% terbium ions, calculated as Tb 4 O 7 .

25 . Method according to claim 8 , in which the starting glass comprises 0.3 to 0.7 wt.-% terbium ions, calculated as Tb 4 O 7 .

26 . Method according to claim 9 , in which the starting glass comprises 1.0 to 7.0 wt.-% alkaline earth metal oxide.

27 . Method according to claim 13 for the preparation of a glass ceramic which comprises 10.0 to 30.0 wt.-% SiO 2 as crystal phase.

Assignees

• Ivoclar Vivadent Ag

Inventors

• Rampf Markus
• Krolikowski Sebastian
• Ritzberger Christian
• Holand Wolfram
• Schweiger Marcel

Classifications

• A61C13/0003

  Making bridge-work, inlays, implants or the like · CPC title

• A61C13/083

  Porcelain or ceramic teeth {(A61C13/081 takes precedence; preparations A61K6/80)} · CPC title

• C03C3/095

  containing rare earths · CPC title

• C03C4/12

  for luminescent glass; for fluorescent glass · CPC title

• C03C4/02

  for coloured glass · CPC title