Inlays and onlays are are extremely durable ceramic (or gold) restorations that are placed on posterior (usually Molar) teeth where strength is required to endure the heavy chewing forces in that area of the mouth. These restorations are often indicated for replacing existing, large defective fillings or worn teeth that have lost most of their enamel. Often it is unnecessary to grind down good remaining tooth structure for a full crown restoration and therefore only the “weak” part of the tooth and/or old filling is removed, leaving the stronger part intact. An impression of the preparation is taken, and a temporary restoration is placed while the dental lab technician fabricates the ceramic restoration. Once the restoration is made, it is “bonded” into or onto the tooth providing essentially the same strength and durability as a crown but more conservative in removal of natural tooth structure.
Following is an actual case provided by Dr. Russell West for a ceramic onlay restoration
A large existing composite filling is present which is breaking down and requires replacement. Alternative treatments of either replacing the filling with new a new composite restoration, which we deemed to provide inadequate strength over time, or a crown, which involved removal of excessive natural tooth structure were discounted. A more conservative ceramic onlay was chosen to be the treatment of choice. The arrow points to strong remaining tooth structure that we would like to preserve.
Typical onlay preparation with the arrows pointing to the preserved tooth structure which will be strong and supportive for the onlay.
Ceramic onlay after bonding to the tooth. The restoration is virtually seamless with the tooth providing a strong, durable, natural-appearing restoration.