Lithium silicate glass ceramic and method for fabrication of dental appliances
AssigneeJames R. Glidewell Dental Ceramics, Inc.
InventorRodolfo Castillo
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Abstract
The present invention relates to preparing an improved lithium silicate glass ceramic for the manufacture of blocks for dental appliance fabrication using a CAD/CAM process. The lithium silicate material has a chemical composition that is different from those reported in the prior art including 8 to 10% of germanium dioxide in the final composition. The softening points are close to the crystallization final temperature of 830° C. indicating that the samples will support the temperature process without shape deformation. The resulting material has improved castability and higher density.
Claims9
A lithium silicate ceramic glass made from a composition mixture comprising:
- up to about 59% wt SiO2;
- up to about 20% wt Li2O;
- up to about 10% wt GeO2;
- and
- selected amounts % wt of at least Al2O3, K2O, B2O3, CeO2 and P2O5.
A lithium silicate ceramic glass made from a composition mixture comprising:
- about 54.3% wt SiO2;
- about 15.2% wt Li2O;
- and
- about 7.6% wt GeO2.
A method of fabricating dental restorations made of lithium silicate glass;
- the method comprising the steps of:
- (a) blending a mix of precursors;
- (b) ball milling the mix to homogenize components of the mix;
- (c) melting the resultant mix of step (b) for about 1 to 3 hours at a temperature of about 1400° to 1500° C.;
- (d) pouring the melt of step (c) into graphite molds to form shaped blanks and cooling such blanks to room temperature;
- (e) heating the blanks of step (d) at a temperature of 625° to 650° C. for 10 to 60 minutes;
- (f) milling the blanks of step (e) into dental restorations;
- and
- (g) heating the restorations of step (f) at a temperature of 760° to 830° C.
Dependencies are inferred from the claim text.