Lithium silicate glass ceramic material useful in the manufacture of dental framework comprises silicon oxide, lithium oxide, potassium oxide, aluminium oxide and phosphorus pentoxide

摘要

A lithium silicate glass ceramic material (I) comprises (wt.%): silicon oxide (SiO 2) (64 - 73), lithium oxide (Li 2O) (13 - 17), potassium oxide (K 2O) (2 - 5), aluminium oxide (Al 2O 3) and phosphorus pentoxide (P 2O 5). Independent claims are included for the following: (1) preparation (M1) of a lithium silicate blank involving a) producing a melt of a starting glass containing the initial components SiO 2, Li 2O, K 2O, Al 2O 3 and P 2O 5 as the main components, b) pouring the melt of the starting glass into a mould to form a starting glass blank (B1) and cooling the glass blank to room temperature, c) subjecting the starting glass blank to a first heat treatment at a first temperature to give a glass product (G1) which contains nuclei suitable for forming lithium metasilicate crystals, d) 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 blank (B2) with lithium metasilicate crystal as the main crystalline phase; (2) a blank made from the lithium silicate material and having a holder to fix it in a machine; and (3) manufacture (M2) of the lithium silicate restoration by coating the dental restoration with the lithium silicate blank.