When a tooth is too damaged for a filling, but not damaged enough for a crown, you have to find middle ground. That’s where inlays and onlays come in. If you try to fill a severely damaged tooth, this will only further weaken the tooth structure and cause breakage or the need for a root canal. And capping a tooth that’s not ready for it will remove more tooth structure than necessary.
So, what do inlays and onlays do? Technically, they do the same thing. They offer the same restoration to teeth by fixing large cavities without having to use a crown. Inlays and onlays simply cover different sections of the tooth. Inlays fill spaces between the “cusps” of teeth- between the rounded edges- at the center of the tooth’s surface. Onlays cover one or more cusps or the entire biting surface of the tooth- sometimes these are referred to as “partial crowns.”
There are two types of onlays, direct and indirect. Direct onlays are made in a dental office, while indirect onlays are made in a dental laboratory.
The best way to avoid having to get inlays or onlays put on is with good dental hygiene. Brushing and flossing regularly as well as visiting your dentist twice a year will keep your teeth from decaying and allow your dentist to catch any problem areas as they arise.