| 摘要 |
The desired optical characteristics are obtained in ceramic teeth by incorporating opacifiers of a particle size approximating to the wavelength of visible light, preferably between 0.8 and 0.4 microns. The parent substance is preferably feldspar or sodium or potassium aluminium silicate. Suitable materials as opacifiers are aluminium oxide, quartz, tin oxide and zirconium oxide. They may be added to the ceramic substance by mixing prior to vitrification, formed by crystallization within the melt, the process being so controlled as to produce particles of the desired size, or precipitated on the particles of the ceramic compound. |
