Degradation of bioceramics

Abstract

After roughly 100 years of controlled clinical use, the in vivo and in vitro degradation mechanisms of ceramic materials are still largely unknown. In bioinert ceramics such as alumina and zirconia used in orthopedics, crack propagation mechanisms are well known, but their interactions with other degradation mechanisms (low-temperature degradation, shocks, wear, dissolution, etc.) and the in vivo environment remain to be firmly established. In bioactive ceramics like calcium phosphates and bioactive glasses, dissolution-precipitation processes play a major role on both degradation of the implant and biological efficiency. Even without the ambition to be exhaustive, it is the purpose of this chapter to present the degradation mechanisms of ceramic implants, both inert and bioactive, and the interactions between them and with their environment.