Some bioactive glasses and glass-ceramics are already clinically used widely as periodontal implants, artifical vertebra etc. Factors governing their bioactivity have been considerably revealed. It was found that Si-OH and Ti-OH groups on their surfaces induce the formation of bonelike apatite layer, which is responsible for their bonding with bone in the living body. This enabled the author to design bioactive metals and organic polymers by utilizing an alkali or alkaline earth silicate or titanate glass. Application of glasses and glass-ceramic to hyperthermia treatment and radiotherapy of cancer also considerably progressed. A silica glass implanted with a large amount of P+ ion at high energy is also believed to be useful for radiotherapy.
