Cavities require dental fillings, and the majority of the population suffers from at least one cavity in a lifetime. That means that most people are familiar with what a dental filling is. When you have a cavity, your dentist will remove the decay, sterilize the area and fill the cavity with either a metal filling, or a composite resin (white) filling to restore and strengthen the tooth. But, there are two types of fillings that you may not be familiar with: inlays and onlays.

What is an Inlay?

Inlays and onlays perform the same function as a dental filling only they are considered indirect restorations while a dental filling is a direct restoration. Dental fillings are referred to as direct restorations because they are placed ““directly” into the tooth while in the office during your first visit. Indirect restorations, on the other hand, are fabricated in a dental lab and then placed into the tooth during a second visit. Therefore, they are “indirectly” placed. Hence, “indirect” restoration. An “inlay” is bonded within the center of a tooth, and is used when the cavity is too large for a traditional dental filling to be effective.

What is an Onlay?

Onlays are the treatment of choice when the tooth is too damaged for a filling or inlay, but not damaged enough to require a crown. Onlays are placed into the center of the tooth as well, but include the restoration of one or more cusps of the tooth.  Therefore, the also lay “on” the tooth. Hence the term onlay.