An onlay is a restoration made of porcelain or gold that can repair a heavily damaged tooth. An onlay is an indirect restoration that incorporates a cusp by covering, or onlaying, the missing cusp. This type of restoration conserves natural tooth structure by replacing only the broken parts of the tooth.
What is a CEREC?
A CEREC is a type of porcelain onlay that is made using CAD/CAM technology. Unlike a traditional porcelain onlay, a CEREC can be made in one visit. This saves time and minimizes discomfort. A CEREC is made by preparing a tooth for the onlay, scanning the tooth, and using a computer aided design process to fabricate the restoration. The onlay is then milled in a robotic unit that carves the restoration out of a porcelain block in about twenty minutes. The restoration is then cemented onto the prepared tooth.
What alternatives exist to an onlay?
A crown may be used in place of an onlay. Unlike the onlay, the crown covers the entire tooth. This conserves less tooth structure but may offer advantages in retention and strength of the restoration.