Advanced Ceramic

Bioceramic materials have developed into a very powerful driver of advanced ceramics research and development. For many years bioceramics, both bioinert materials such as alumina, zirconia and, to a limited extent titania and bioconductive materials such as hydroxyapatite, tricalcium phosphate and calcium phosphate cements, have been used successfully in clinical practice. In addition, applications continue to emerge that use biomaterials for medical devices. An excellent account of the wide range of bioceramics , in which issues of the significance of the structure, mechanical properties and biological interaction of biomaterials are discussed, and their clinical applications in joint replacement, bone grafts, tissue engineering, and dentistry are reviewed.

Basic Aspects of Biomineralization
Human bone is a strong, tough, and highly durable composite material which consists of about 70% micro - to nanocrystalline biological apatite and 30% micro fibrils of collagen I, all of which are organized in a hierarchical manner, as shown in Figure 10.1 anocrystals of bioapatite that are about 30 × 50 × 2 nm3 in size (G and H in Figure 10.1) are arranged with their c – axes parallel to the extension of fi ve collagen molecules which themselves consist of triple helical strands of collagen fibers to form a microfibril (F). These inorganic – organic composite microfi brils are bundled together to form larger fibrils (E) that are, in turn, grouped to form even larger mineralized fi bers (D). Hence, a spatially hierarchical organization exists that forms the basic structural units of bone. During the formation of bone, the collagen I matrix develops first; this is followed by a second step in which the hydroxyapatite nanocrystals become embedded.