Rebuild a damaged tooth while covering only the cusps that need protection.

An onlay sits between a filling and a full crown in coverage.

Onlays may be considered when decay, fracture, or a large failing restoration has weakened part of a back tooth, including one or more cusps. They are sometimes called partial crowns because they provide more coverage than an inlay but less than a full crown.

The goal is to preserve sound tooth structure while strengthening the areas that bear chewing forces. Not every damaged tooth is suitable: the remaining enamel, crack pattern, bite, and ability to isolate the tooth all affect the choice.

What treatment involves

The tooth is prepared by removing decay, damaged material, and any unsupported structure. A digital scan or impression captures the shape. Depending on the case, the onlay may be produced in the office with CAD/CAM technology or by a dental laboratory.

At placement, the dentist checks the edges, neighboring contacts, and bite before bonding or cementing the onlay. A temporary restoration may be used when the final onlay is made at a laboratory.

Protecting the result

• Brush with fluoride toothpaste and clean the edges between teeth every day.
• Avoid chewing hard nonfood objects or using the restored tooth as a tool.
• Ask about a protective appliance if clenching or grinding is present.
• Report new pain, a changed bite, looseness, or a fracture promptly.