Glass Ceramic Crowns (Empress, E-max)
Classical metal supported porcelain crowns are prepared by processing porcelain on metal alloy. This substructure is gray color. Porcelain is processed on the gray substructure suitable for tooth coloring. However, in recent years the substructure is provided with glass ceramics called Empress. The color of the glass ceramic used as the substructure is white. The porcelain is processed suitable for tooth-color.
Especially in frontal restorations, glass ceramic crowns should be preferred. Glass ceramic crowns do not contain metal in the substructures, so their light transmittance is very high. In this way, it is possible to make teeth in the natural way that even the dentist can not recognize without examination. The most aesthetic crowns are made with glass ceramics. They also provides more aesthetic appearance than zirconia. In both zirconia and glass ceramics, there is no gray line in the gum seen in metal crowns.
While glass ceramic is used in the front teeth; zirconia should be preferred in the molar teeth where the chewing pressure is high. Because glass ceramics are very aesthetic as well as fragile. CAD-CAM technology is used to produce glass ceramics. However, it is not possible to talk about aesthetics in a fabricated production. Glass ceramics are absolutely produced after taking measurements by an experienced dentist and they are produced as a special ‘hand made’ by an artist ceramist.