What Inlays and Onlays Can Address
These restorations are generally used when a tooth has more extensive damage than a straightforward filling can address — for example, where decay or a previous filling covers a larger area, or where more support is needed than a direct filling can provide. An inlay sits within the contours of the tooth; an onlay extends to cover one or more of the biting surfaces.
The Difference Between an Inlay and an Onlay
An inlay fits within the existing structure of the tooth, filling a cavity from within. An onlay is generally larger, extending over part or all of the tooth's biting surface. Which of the two applies to your own tooth depends on how much of the tooth needs to be restored — an assessment question, not something decided on this page.
How Inlays and Onlays Differ from Fillings and Crowns
Unlike a filling, which is shaped directly in the tooth during a single visit, an inlay or onlay is made in a laboratory from an impression or scan, then fitted at a later appointment. Compared with a crown, an inlay or onlay generally preserves more of the natural tooth structure, since it doesn't need to cover the whole tooth. See Dental Fillings and Dental Crowns for those alternatives.
Assessment and Planning
Assessment generally includes an examination of the tooth, often with an X-ray, to establish how much of the tooth is affected and whether a direct filling, an indirect inlay or onlay, or a crown would be more appropriate. This page describes the treatment; it does not decide which option suits you.
What to Expect in General Terms
Providing an inlay or onlay generally involves two appointments. At the first, the damaged material is removed and an impression or scan is taken, usually with a temporary filling placed in the meantime. At the second, once the restoration has been made, it's checked for fit and cemented onto the tooth.
Considerations and Limitations
As with any restoration, inlays and onlays don't last indefinitely, and may eventually need repair or replacement. Some sensitivity in the period after fitting is a general consideration your dentist would discuss with you. Outcomes vary between individuals.
Looking After an Inlay or Onlay
An inlay or onlay is generally cared for like a natural tooth, alongside regular dental check-ups to monitor its condition over time.
Related Treatments
If your damage turns out to be more contained, Dental Fillings may be the simpler route. Where an inlay or onlay wouldn't provide enough coverage, Dental Crowns covers the full-coverage alternative.
General information only — every treatment decision follows an individual clinical assessment.