An onlay is similar to an inlay except that it covers the whole of the biting surface of the tooth in addition to filling any holes in the tooth.

Onlays are essentially the same as inlays, except that they restore a larger portion of the tooth including part or all of a cusp.

a laboratory-fabricated porcelain tooth restoration that fills and restores a defect in the tooth. It extends over the edges of the defect to hold the remaining parts of the tooth together, thereby strengthening the tooth.