Inlays & Onlays

When more than half of the tooth’s biting surface is damaged a dentist will often use inlays or onlays.

What are inlays and onlays?

Inlays and onlays can be made of porcelain, gold, or a composite resin. They are bonded to the damaged area of the tooth.  An inlay remains inside the cusp tips of the tooth. An onlay is a more substantial reconstruction and extends out over one or more of the cusps of the tooth.

Traditionally, gold has been the material of choice for inlays and onlays.  Gold inlays and onlays have longevity superior to other materials.  However, many patients do not accept the gold color when it is visible during speaking or smiling.,  Tooth-colored materials are also available.  They include lithium disilicate, a type of porcelain, or composite resin.   Composite resin is a very good material, but it wears at a faster rate than porcelain.  A recent study reviewed in the Journal of Evidence-Based Dentistry (Congiusta, 2017) found that composite resin inlays have no better longevity than composite resin done “directly” in the mouth.  In this case, the additional cost of an indirect procedure does not appear to be justified.

How are inlays and onlays applied?

Inlays and onlays require two appointments to complete.  They are made outside the mouth, and are called “indirect.” During the first visit, the filling being replaced or the damaged or decaying area of the tooth is removed and the tooth is prepared for the inlay or onlay. An impression of the tooth is made, and the tooth is sealed with a temporary inlay or onlay.  The completed inlay or onlay is cemented or bonded to the tooth at the second appointment. 

Considerations for Inlays and Onlays

Inlays and onlays are used when damage to the tooth is not extensive enough to merit a dental crown.