ONLAYS and INLAYS These are special fillings that are similar to composite or tooth-colored fillings except that they are made in a dental laboratory and require two visits before being placed.
Inlays and onlays are more durable and, with proper care, can last much longer than traditional fillings – up to 30 years. They can be made of tooth-colored composite resin, porcelain, or gold.
Inlays and onlays are special fillings that are used when not enough tooth structure remains to support a filling but the tooth is not so severely damaged that it needs a crown.
Inlays are similar to fillings but the entire work lies within the cusps (bumps) on the chewing surface of the tooth. Onlays are more extensive than inlays,covering one or more cusps. Onlays are sometimes called partial crowns.