Glass ceramic materials have the best compatibility with the optical properties of teeth and their dentin. Glass is a three-dimensional network of atoms that does not have a regular spatial pattern. In these materials, there is no regular spatial pattern (in terms of distance or angle) between the nearest neighbor and the next neighbor; Therefore, the glass structure is amorphous. (or has an amorphous structure, generally, the glasses used in dental ceramics are derived from a group of minerals called feldspars and are made on the basis of silica (silicon oxide) and alumina (aluminum oxide).
