Ceramics is the only biomaterials that up-regulate cells differentation process. For example, apatite ceramics up-regulate differentation of bone-related and connective tissue related cells. As a result, apatite and its related bioceramics hashave been used in clinics, especially for the regeneration and reconstruction of bone tissue defects. Despite the long history of apatite ceramics use, detailed mechanism of the up-regulation of osteoblasts by apatite ceramics has not been clarified up to date. ÐLs unfortunate current situation may arise, at least in part, to the usefulness of apatite ceramics for clinical use. Clinical application studies have been focused more attention rather than science of apatite.