Inlays and onlays can be made of porcelain, gold, or composite resin. These pieces are bonded to the damaged area of the tooth. An inlay, which is similar to a filling, is used inside the cusp tips of the tooth. An onlay is a more substantial reconstruction, similar to the inlay but extending out over one or more of the cusps of the tooth.
Traditionally, gold has been the material of choice for inlays and onlays. In recent years, however, porcelain has become increasingly popular due to its strength and color which can potentially match the natural color of your teeth.