Research and development on surface bioactivity methods of titanium and its alloys

Titanium and its alloys have been applied widely in hard tissue replacements of human body. Many methods were developed in order to improve their surface bioactivity, including physical methods, chemical methods and electrochemical methods. The surface bioactivity method of titanium and its alloys are reviewed in present paper. The processing and bioactivity mechanism of every method are introduced, and the advantages and disadvantages of those methods are also presented. Comparing with physical methods, chemical methods have more advantages as follows: simple equipment and process, uniform coatings on complex surface, and the similar structure and compositions of coatings to those of natural bone. For chemical methods, it is necessary to enhance the efficiency and the bonding strength between coatings and substrates. And the effect of long-term implantation and the bioactivity theory of chemical methods are demanded to research deeply.