They are created using an impression of the tooth cavity which is then replicated using hard-wearing materials such as metal or porcelain. The Inlay or Onlay is then fitted to the cavity in the tooth and firmly sealed in place.
If a cavity develops within a larger back tooth such as a molar, a traditional filling may not be strong enough to maintain the structure of the tooth. Because these larger teeth must withstand a lot of pressure from chewing, Inlays are often used to provide extra strength or cover large areas.
Sometimes cavities and other damage to teeth can lead to large portions of a tooth requiring repair. For example, the cavities that develop in molars can occur in the very middle of the tooth, so a large and deep Onlay may be needed. Made using the same method as Inlays, they can fill large portions of missing teeth, including the cusps, or points, of the teeth.