Lithium disilicate glass-ceramics
US6802894B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 25, 2002 |
| Grant date | Oct 12, 2004 |
| Priority date | — |
| Expiry date | Jun 25, 2022 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03C10/0027
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
Abstract
This invention is directed to lithium disilicate (Li2Si2O5) based glass-ceramics comprising silica, lithium oxide, alumina, potassium oxide and phosphorus pentoxide. The glass-ceramics are useful in the fabrication of single and multi-unit dental restorations (e.g. anterior bridges) made by heat pressing into refractory investment molds produced using lost wax techniques. The glass-ceramics have good pressability, i.e., the ability to be formed into dental articles by heat-pressing using commercially available equipment. In accordance with one embodiment directed to the process of making the glass-ceramics, the compositions herein are melted at about 1200 ° to about 1600 ° C., thereafter cast into steel molds in the shape of cylindrical blanks (pellets), or alternately, cooled to the crystallization temperature. The resulting glass blank are heat-treated to form glass-ceramic blanks via a one or two step heat-treatment cycle preferably in the temperature range of about 400 ° to about 1100 ° C. The resulting glass-ceramic pressable pellets and/or blanks of desired shapes, sizes and structures are later pressed into dental restorations. Alternatively, instead of formi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.