Inlays and onlays are an alternative to fillings. These restorations are used to replace part of a tooth that has been lost because of breakage or decay. Inlays and onlays are stronger and can last longer than regular fillings and are a good option for restoring back teeth.
Sometimes inlays and onlays are called partial crowns because they use the existing tooth as a base, but do not cover up the entire tooth like a crown. The difference between an inlay and onlay is that an inlay is done when there is no damage to the cusps of the tooth and the inlay can be placed right inside the tooth while an onlay is used when the damage is more extensive to replace one or more cusps of the tooth.
More conservative than a crown, inlays and onlays still require more appointments than a regular filling because they are made in a dental laboratory. During the first visit, the decayed part of the tooth is removed and the tooth is prepared to receive the inlay or onlay. A mold is made and this is sent to the dental laboratory to create a restoration made from porcelain, or gold. Since it takes the dental lab about 2-3 weeks to make your restoration, a temporary is placed on the tooth until you come back for the second visit. At the next visit, the inlay or onlay is placed on the tooth and permanently bonded to the tooth with cement. Porcelain inlays and onlays appear completely natural and the repair is cosmetically undetectable.