Inlays & OnlaysTraditional fillings aren’t always the best choice, so we may recommend inlay or onlay restorations. These types of porcelain restorations are perfect for patients with moderate decay, especially when the tooth cannot accept a traditional composite filling. Those who benefit from inlay or onlay treatment don’t require a crown after the restoration, and the original structure of the tooth is strengthened. An inlay is quite similar to a filling, covering the inside of the cusps of the tooth to be restored. An onlay extends over one or more of the cusps.