バイオセラミックスの力学的性質

抄録

Ceramics are harder than metals and polymers and have excellent wear resistance, high mechanical strength, and high chemical stability. In addition, these properties can be arbitrarily controlled depending on the compositions and microstructures of the materials. Therefore, ceramics are widely used in orthopedic surgery as artificial joints and bones. Such ceramics for biomedical applications are called bioceramics. In the application of bioceramics, the mechanical property is one of the most important material characteristics. For example, alumina (Al₂O₃) or zirconia (ZrO₂) ceramics are often used for the sliding parts of artificial joints that require excellent wear resistance and appropriate mechanical strength. Bioceramics used in orthopedics can be divided into three types, bioinert, bioactive, and bioabsorbable ceramics, depending on the biological response when implanted into a bone defect. In this review paper, firstly, we describe the mechanical properties of Al₂O₃ and ZrO₂ ceramics as typical bioinert ceramics, then the mechanical properties of Na₂OCaO-SiO₂-P₂O₅ glass, hydroxyapatite/beta-type tricalcium phosphate biphase ceramics and glass-ceramic containing fluorapatite and wollastonite as typical bioactive ceramics were reviewed. The mechanical properties of calcium phosphate cements and calcium phosphate-polymer composites including recently developed soft ones were also introduced.