An onlay is a restoration that is made to restore only the parts of a tooth and filling that have failed, while maintaining remaining tooth structure that is sound. Onlays have been done for many years, but they have recently been recommended more often.

Onlays can be considered as more conservative care. When possible onlays are preferred because they require less tooth to be involved with the preparation, thus making leaving as much of your natural tooth as possible.

As with crowns there are many of the same reasons why a tooth might be diagnosed to have an onlay done::

• Fractured or broken tooth.
• Excessive amount of decay.
• Tooth has existing large filling with decay and/or marginal breakdown of old filling material.
• Improve the esthestics.