High expansion dental crown core ceramic composition
US4576922A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 9, 1985 |
| Grant date | Mar 18, 1986 |
| Priority date | — |
| Expiry date | Jan 9, 2005 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B35/053
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
Abstract
A strong white ceramic composition and method of making the same wherein said composition is characterized by an average coefficient of thermal expansion over the range of 25.degree. C. to 500.degree. C. ("Proposed American National Standards Institute/American Dental Association Specification No. 38.1 For Porcelain-Alloy Systems") of between 14 to 16.times.10.sup.-6 /.degree.C. and a transverse strength of about 18,000 psi or even greater. The ceramic composition comprises about 40 to 60% by weight crystalline magnesium oxide particles (e.g., 74 .mu.m ) dispersed in a modified silicate glass containing at least 3% by weight of dissolved ZrO.sub.2, TiO.sub.2 or mixtures thereof and is made by firing a powdered mixture of MgO.sub.2 and modified silicate glass at about 1150.degree. C. for sufficient time to produce a fine dispersion of forsterite (Mg.sub.2 SiO.sub.4) in the continuous glass matrix phase along with the crystalline magnesia particles. Such ceramic compositions are useful in high expansion dental crown core applications.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.