Bioceramics

At the outset, we should note that the classification of biomaterials appropriately follows the traditional categories of structural materials, viz. metals, ceramics (and glasses), polymers, and composites there is a tendency to focus on metallic materials and then nonmetallic materials in relation to more established metallic applications. A central issue surrounding contemporary engineered materials is
“materials substitute ion.” The use of lower-density polymers and composites in place of metallic auto body panels and the use of more refractory ceramics in place of metallic engine parts are important examples. The history of biomaterials, in general, is often given in terms of metallic implants (Fraker and Ruff 1977). For example, the use of metals for orthopedic applications dates from ancient times. Up to 1875, relatively pure metals such as gold, silver, and copper were primarily used, but not always with great success due to poor surgical conditions. Engineered metal alloys became more widely used between 1875 and 1925 coincident with substantial improvements in surgical techniques. The period since 1925 can be considered the modern era of metallic biomaterials, with the development of a wide variety of orthopedic applications for which the dominant alloys of choice are 316L stainless steel, Co-Cr alloys, and Ti-6Al-4V. A typical metal alloy for a modern biomedical application (hip replacement)
Polymeric biomaterials are used in a wide variety of surgical applications,
such as blood vessel prostheses, tissue adhesives, heart valves, lenses, and
sutures (Ratner 1993). Evidence exists in papyrus records for the use of linen sutures for closing wounds 4,000 years ago. Catgut was introduced for sutures in the second century. Silk was used for this purpose in the 11th century. A variety of contemporary synthetic polymers are now used in modern surgery. Polyethylene, polyester, polyglycolic acid, and nylon are examples .