ABSTRACT
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 (Shackelford 1996). In effect, any structural application for medical purposes makes the engineered material a “biomedical” one. As with the broad treatment of the field of ªmaterials science and engineering,º (Shackelford 1996) 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 substitution.” 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. In this book, dedicated to the topic of ªbioceramics,º we shall remain aware of the relationship of ceramics to the alternate applications of metals, polymers, and composites in biomedicine.
