Metallic biomaterials.

Ti alloys composed of nontoxic and allergy-free elements and Ni-free stainless steels and Co-Cr alloys are currently being developed. Ni-free Ti alloys exhibiting superelastic behavior, or the shape memory effect, are also being developed. beta-type Ti alloy with a low elastic modulus has proved to be effective for inhibiting bone absorption and enhancing bone remodeling. Simple bioactive surface modifications such as alkali-treatment processes and the calcium phosphate glass-ceramic dip-coating method are applicable to newly developed beta-type Ti alloys such as lowmodulus Ti-29Nb-13Ta-4.6Zr. Blood-compatible polymers such as poly(ethylene glycol) have been successfully fixed on the surface of Ti via chemical bonding by an electrodeposition method. Ti alloys for dental applications have also been recently developed.