**1.2 Crowns and bridges**

Crown is technically a "Cap" placed on a tooth to protect it from fracture or sensitivity. On the other hand a bridge is a fixed replacement of missing teeth, with support from adjacent teeth. Both of these function similarly on biological and biomechanical terms, hence discussed together. These are of either *Porcelain fused to metal* (PFMs) or *full ceramics*. In case of PFMs, a metal core is placed in the tooth surface and ceramic is built on it. This is done by initially preparing the metallic portion by conventional casting techniques. Then the ceramic powder is incrementally painted on it and sintered. This is followed by glazing. In case of full ceramics, the wax pattern is prepared for the crown, it is invested and mould space prepared by lost wax technique. The ceramic is fused and typically pressed into the mould space.

Fig. 1. Ceramic Crowns and their anatomy.

Fig. 2. Clinical picture of crown. Note pink ceramic used of gum recession.

The classification based on microstructure will be dealt with in detail and an idea of classification by processing technique is added in this review. Other classifications are of

Basically ceramics are used as indirect restorative materials such as crowns and bridges, Inlays/Onlays and dental implants. Recently ceramic braces are used in orthodontics.

Crown is technically a "Cap" placed on a tooth to protect it from fracture or sensitivity. On the other hand a bridge is a fixed replacement of missing teeth, with support from adjacent teeth. Both of these function similarly on biological and biomechanical terms, hence discussed together. These are of either *Porcelain fused to metal* (PFMs) or *full ceramics*. In case of PFMs, a metal core is placed in the tooth surface and ceramic is built on it. This is done by initially preparing the metallic portion by conventional casting techniques. Then the ceramic powder is incrementally painted on it and sintered. This is followed by glazing. In case of full ceramics, the wax pattern is prepared for the crown, it is invested and mould space prepared by lost wax

technique. The ceramic is fused and typically pressed into the mould space.

Fig. 2. Clinical picture of crown. Note pink ceramic used of gum recession.

academic interest.

**1.2 Crowns and bridges** 

Fig. 1. Ceramic Crowns and their anatomy.

Fig. 3. All Ceramic Crown.

Similarly, ceramic teeth are manufactured in various shades, shapes and sizes to be used in complete dentures. Also, in case of gum recession, in fixed prosthesis, pink coloured ceramics are placed in the lost gum region to make it look natural.
