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US 7,871,948 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 metasilicate 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
- ZrO2
- 0.1-4.0
- 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, and
- (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.
18 more elements
Dependencies are inferred from the claim text.