Biocompatibility of alkali treated titanium and titanium alloy

In this investigation, conventional Ti, Ti-6Al-4V specimens with and without surface treatment with alkali-and heat-treatment were used as implanted material in mice. Conventional SUS316L was also used for comparison. The implanted site was in the abdominal connective tissue. The implants were kept there for three months and then their biocompatibility was evaluated by in vitro and in vivo experiments. The main results obtained were as follows: (1) When evaluated by immersing in Hank's solution, which has similar ion concentrations to those of human blood, the alkali-treated specimens are much better because an apatite layer is formed, which accelerates the connection with the bone. (2) The number of macrophage, which is known to increase as the inflammation reaction proceeds, is much less for the alkali-treated specimens than the others. (3) The average thickness of the fibrous capsule formed around the implant is much thinner for the alkali-treated specimens than the others. These results show that the surface-treatment performed by the present study is very effective for the improvement of biocompatibility.