Onlays fit over your tooth’s biting surface and are made of a solid piece of porcelain, composite, resin, or gold. This type of restoration is used to fix a tooth that has been damaged by decay or injury. Onlays are similar to inlays but differ in the amount of your tooth they cover. Onlays go over the cusp (or cusps) of your tooth, whereas inlays fill the space between your cusps.
Dental onlays can be thought of as a middle ground between filling a cavity and removing part of your tooth to cap it with a crown. Onlays are similar to crowns but replace less of the healthy tooth, making them a less extreme option.
Situations when a dental professional may recommend an onlay:
- When a cusp of your tooth is damaged so an inlay or filling can’t be used
- If you have a cavity on a tooth with a weak structure that may crack if restored with a regular filling
- To avoid the removal of the amount of natural tooth structure usually required to place a crown
According to the American College of Prosthodontists, it can be challenging to determine which situation warrants a filling, crown, inlay, or onlay. For this reason, it’s essential to consult your dental professional for their expert opinion.