The Chairside Instructor 26 Inlays and onlays are often used to restore teeth that have been damaged by decay and wear. They are made in a dental office or lab and are typically placed on the chewing surfaces of the back teeth or molars. Inlays and onlays are very durable. They are often used when the area to be filled is too large for a regular filling, but not large enough to need a crown. Before An onlay restores one or more peaks of the tooth (cusps) or the entire biting surface. An inlay fits within the contours of a tooth, in an area that the dentist has prepared. Decay Inlay Onlay Before the inlay is placed Before the onlay is placed After the inlay is placed After the onlay is placed Inlay Onlay Inlays and Onlays Decay, Cavities and Restorations