Lithium silicate glass ceramic and method for fabrication of dental appliances
View Patent ↗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.
1. A lithium silicate ceramic glass made from a composition mixture comprising:
about 54.3% wt SiO 2 ;
about 15.2% wt Li 2 O; and
about 7.6% wt GeO 2 .
2. The lithium silicate ceramic glass recited in claim 1 wherein said composition mixture also comprises at least 1.9% wt of each of Al 2 O 3 , K 2 O, P 2 O 5 , ZrO 2 , CeO 2 , Pr 2 O 3 and Sm 2 O 3 .
3. The lithium silicate ceramic glass recited in claim 2 further comprising one or more of the following additional components TiO 2 , Er 2 O 3 and V 2 O 5 .
4. A Lithium silicate material recited in claim 3 wherein the lithium silicate crystals form 50 to 60 vol % of the lithium silicate material.