Bioceramics physical/mechanical properties

Bone is an anisotropic and viscoelastic ceramic matrix composite and is distinct from conventional ceramics. Its mechanical properties depend on its porosity, degree of mineralization, collagen fiber orientation, and other structural details. The data in Table 18.1 may be used to compare the physical and mechanical properties of bone, hydroxyapatite (the major mineral in bone, and hence, the most relevant material as a bioceramic), and CBPCs. 

Relatively bioinert ceramics maintain their physical and mechanical properties while in the host. They resist corrosion and wear and have aU the properties listed for bioceramics in Table 39.1. Examples of relatively bioinert ceramics are dense and porous aluminum oxides, zirconia ceramics, and single phase calcium aluminates (Table 39.2). Relatively bioinert ceramics are typically used as structural-support... 

A strong interest in the use of ceramics for biomedical engineering applications developed in the late 1960 s. Used initially as alternatives to metallic materials in order to increase the biocompatibility of implants, bioceramics have become a diverse class of biomaterials presently including three basic types relatively bioinert ceramics maintain their physical and mechanical properties in the host and form a fibrous tissue of variable thickness surface reactive bioceramics which form a direct chemical bonds with the host and bioresorbable ceramics that are dissolved with the time and the surrounding tissue replaces it. 

Bioinert Relatively bioinert ceramics maintain their physical and mechanical properties while in the host. They are those stable bioceramics that do not react appreciably when they are implanted in the body. The implant does not form a bond with bone. Alumina (a-Al203) is a typical example of ceramic bioinert. Other examples, as we see next, are the zirconia ceramics (Zr02) and pirolitics carbon ceramics. 

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