Dental inlays and onlays are both excellent options for fillings and are a common dental procedure to address tooth decay.
A dental inlay is a restoration that is pre-molded to fill the space in between the cusps, or rounded edges, at the center of a tooth. It may be recommended to repair a tooth that has sustained damage from an injury or decay that does not affect the cusps of a tooth.
To place an inlay, the mouth is first numbed using a local anesthetic. The tooth is then drilled to remove the decay and clean the area. An impression is taken of the tooth, which is sent to a dental laboratory where the inlay is made. Inlays can be made of porcelain or composite resin and color-matched to the natural teeth.
Inlays are generally more durable than regular fillings made of composite or amalgam, but gold inlays are the most durable (though also the most expensive) material available.
Like an inlay, a dental onlay is also a pre-molded tooth restoration, although it is made to cover one or more cusps and extend over the biting surface of the tooth. (They are sometimes referred to as “partial crowns.”) An onlay may be recommended when the tooth structure is weak and at risk of cracking if a regular filling is used. It can also be used in place of a crown to avoid removing healthy tooth structure.
Onlays can be made of porcelain or ceramic. Gold or resin may be recommended for placement on molars and premolars because they are not as visible in that location and will provide extra strength.
When are inlays or onlays necessary?
Both inlays and onlays can be used to treat different areas of the tooth, but ultimately are used to treat tooth decay. If a tooth becomes too damaged from a cavity to be treated with a filling (which can weaken the remaining structure of the tooth), but is not damaged enough to call for a crown (which requires tooth structure to be removed), the middle-ground solution is an inlay or onlay. This treatment retains as much of the healthy tooth as possible while strengthening the damaged tooth.
Prevention is the key to maintaining healthy teeth and avoiding dental problems and the need for restoration options.