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US 7,867,930 B2Granted
Lithium silicate glass ceramic
AssigneeIvoclar Vivadent AG
InventorsElke Apel, Wolfram Holand, Marcel Schweiger, Christian Ritzberger, Harald Burke, Volker M. Rheinberger
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Abstract
Lithium silicate materials are described which can be easily processed by machining to dental products without undue wear of the tools and which subsequently can be converted into lithium silicate products showing high strength.
Claims29
Process for the preparation of a lithium silicate glass ceramic wherein lithium disilicate is the main crystalline phase comprising the following components:
- Component
- wt.- %
- SiO2
- 64.0-75.0
- Li2O
- 13.0-17.0
- K2O
- 2.0-5.0
- Al2O3
- 0.5-5.0
- Nucleating agent
- 2.0-5.0
- Me(II)O
- 0-3.0
- and which comprises less than 0.1 wt. % of ZnO,
- with Me(II)O being selected from at least one of CaO, BaO, MgO and SrO which comprises
- (a) producing a starting glass containing the components of the glass ceramic,
- (b) subjecting the starting glass to a first heat treatment at a first temperature to give a glass product which contains nuclei suitable for forming lithium metasilicate crystals,
- (c) subjecting the glass product to a second heat treatment at a second temperature which is higher than the first temperature to obtain the lithium silicate glass ceramic with lithium metasilicate as the main crystalline phase,
- and further subjecting the lithium silicate glass ceramic of step (c) to a third heat treatment at a third temperature of 830 to 880° C. for a period of 10 to 60 minutes.
17 more elements
Dependencies are inferred from the claim text.