General Dentistry Inlays/On-lays Inlays and on-lays are porcelain or composite restorations that are bonded to the tooth. An inlay is stronger than a regular “white” filling, as it is fabricated by a laboratory technician. Inlays and on-lays are virtually indistinguishable from natural teeth and discreetly restore teeth to an optimal state of health. An onlay, …