ABSTRACT
This chapter focuses on a general overview of the relatively bioinert, bioactive or surface reactive ceramics, and biodegradable or resorbable bioceramics. Ceramics are refractory, polycrystal line compounds, usually inorganic, including silicates, metallic oxides, carbides and various refractory hydrides, sulfides, and selenides. Among the most important properties of hydroxyapatite as a biomaterial is its excellent biocompatibility. Hydroxyapatite appears to form a direct chemical bond with hard tissues. Relatively bioinert ceramics maintain their physical and mechanical properties while in the host. The main source of high purity alumina is bauxite and native corundum. Pure zirconia can be obtained from chemical conversion of zircon, which is an abundant mineral deposit. The poorly crystalline carbons are thought to contain unassociated or unoriented carbon atoms. Calcium phosphate has been used in the form of artificial bone. Examples of resorbable ceramics are aluminum calcium phosphate, coralline, hydroxyapatite, and tricalcium phosphate. Zinc is essential for human metabolism and is a component of at least 30 metalloenzymes.
