Lithium silicate materials
Lithium silicate materials are described which can be easily processed by machining to dental products without undue wear of the tools.
1. A machinable lithium silicate dental glass-ceramic article comprising lithium metasilicate as the main crystalline phase and exhibiting a flexural strength of greater than 180 MPa.
2. The machinable lithium silicate dental glass-ceramic article of claim 1 wherein the flexural strength is in the range of about 190 to about 400 MPa.
3. The machinable lithium silicate dental glass-ceramic article of claim 1 , wherein the fracture toughness is less than about 2.0 MPam 0.5 .
4. The machinable lithium silicate dental glass-ceramic article of claim 1 , wherein the fracture toughness is less than about 1.5 MPam 0.5 .
5. The machinable lithium silicate dental glass-ceramic article of claim 1 wherein the glass ceramic comprises SiO 2 , Li 2 O and P 2 O 5 or another nucleating agent.
6. The machinable lithium silicate dental glass-ceramic article of claim 1 wherein the machinable phase comprises lamellar or platelet crystals.
7. The machinable lithium silicate dental glass-ceramic article of claim 1 further comprising lithium disilicate.
8. The machinable lithium silicate dental glass-ceramic article of claim 1 machined into an inlay, an onlay, a bridge, an abutment, a facing, a veneer, a facet, a crown, a partial crown, a framework or a coping.
9. The machinable lithium silicate dental glass-ceramic article of claim 5 further comprising one or more of K 2 O, Al 2 O 3 , ZnO, Na 2 O, ZrO 2 , Me II O, and a coloring/fluorescent metal oxide.
10. The machinable lithium silicate dental glass-ceramic article of claim 9 wherein the Me II O comprises CaO, BaO, SrO, MgO or a combination thereof.
11. The machinable lithium silicate dental glass-ceramic article of claim 9 wherein the coloring/fluorescent metal oxide comprises an oxide of Ta, Tb, Y, La, Er, Pr, Ce, Ti, V, Fe, Mn or a combination thereof.
12. The machinable lithium silicate dental glass-ceramic article of claim 1 further comprises a coating thereon.
13. The machinable lithium silicate dental ceramic article of claim 12 wherein the coating comprises glass or a glass ceramic.
14. The machinable lithium silicate dental glass-ceramic article of claim 12 wherein the coating comprises a stain and/or a glaze.
15. The lithium silicate dental glass-ceramic article of claim 1 wherein flexural strength comprises biaxial, 3-point bend or 4-point bend strength.