Biomaterials

Abstract

Alloplastic cranioplasty is an ancient concept. From the Incan use of precious metals, to the first documented use of a synthetic material to repair a cranial defect (Fallopius, sixteenth century), to Meekeren’s use of canine bone in a human subject, the quest for a suitable nonautologous material has been almost epic. In this quest, the characteristics of the ideal bone substitute have been established. The ideal bone substitute should be (1) chemically inert, (2) hypoallergenic or incapable of inducing a foreign-body reaction, (3) easily contoured, (4) stable and durable shape retention, (5) noncarcinogenic, and (6) capable of incorporation into or replacement with living tissue from the recipient. Although this ideal has not been reached, several products are available. The following discussion is based upon the three broad categories of substitutes used in clinical practice: (1) cement pastes, (2) biomaterials replaced by bone, and (3) prefabricated polymers.