Zirconia as a ceramic biomaterial

Zirconia ceramics have several advantages over other ceramic materials, due to the transformation toughening mechanisms operating in their microstruct ure that can give to components made out of them, very interesting mechanic al properties. The research on the use of zirconia ceramics as biomaterials started about twenty years ago, and now zirconia (Y-YZP) is in clinical us e in THR, but developments are in progress for application in other medical devices. Recent developments have concentrated on the chemistry of precurs ors, in forming and sintering processes, and on surface finish of component s. Today's main applications of zirconia ceramics is in THR ball heads. Thi s review takes into account the main results achieved up to now, and is foc used on the role that microstructural characteristics play on the TZP ceram ics behaviour in ball heads, namely mechanical properties and their stabili ty, wear of the UHMWPE paired to TZP, and their influence on biocompatibili ty. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.