| 摘要 |
The invention relates to a blank for producing shaped dental parts which consists entirely of porous glass without crystalline material. The density of the blank is in the range from 50% to 95% of its theoretical density. It has a disc-like shape having a diameter of at least 20 mm. The blank is produced by a process in which glass powder is firstly pressed at a pressure in the range from 10 MPa to 300 MPa and this green body is (pre)sintered at a temperature in the range from 580°C to 750°C to give a blank composed of porous glass without crystalline material. Monolithic shaped dental parts can be obtained from the resulting blank by mechanical machining and subsequent sintering, with a process according to the invention being employed to stabilize the shape of the shaped parts. The glass preferably contains: SiO2 50 - 80% by weight, Al203 3 - 24% by weight, K2O 3-13% by weight, Na2O 3-13% by weight, Li2O 0-4% by weight, B2O3 0-4% by weight, F 0-4% by weight, TiO2 0-8% by weight, ZrO2 0-8% by weight, P2O5 0-4% by weight, SnO2 0-4% by weight, MgO 0-4% by weight, CaO 0-4% by weight, BaO 0-4% by weight, Sb2O3 0-4% by weight, CeO2 0-8% by weight. |
