Development of titanium alloy for implant with high corrosion resistance and prompt bone connectivity

由于钛具有优良的耐腐蚀性和生物相容性，作为生物体内的金属材料，被用于人工髋关节和牙科植入物等。钛与骨的相容性比其他材料更好。但也有植入后因微动等原因被移除的情况。本研究的目的是发展钛种植体的表面修饰方法，以获得坚固和快速的骨。有一种方法叫碱处理，使之成为预期的表面改性方法之一，可直接将骨状磷灰石层提取到钛的表面。该材料浸泡在模拟体液中，根据其上是否有磷灰石沉淀，钛的生物活性是可观的。本研究采用10mmol/L CaCl_2溶液，在200℃下进行水热处理，以预先将少量Ca固定在钛的表面，并关注体内磷灰石的生成机制。纯钛和钛合金处理后的大鼠骨髓成骨细胞的初始附着和增殖速度均高于碱处理。将该处理后的钛种植体植入大鼠胫骨，观察骨与种植体的界面。植入1周后，经此处理的钛的骨接触率为55%以上，而未经处理的钛的骨接触率为5.7%。植入4周后，该数值达到100%左右。以上结果表明，采用氯化钙溶液进行水热处理是一种具有生物活性的钛表面改性方法。

Because titanium has an excellent corrosion resistance and a biocompatibility, it is used for an artificial hip joint and a dental implant, etc. as a metallic material for the living body. The compatibility of titanium with the bone is more excellent than that of other materials. However, there is a case removed after implantation by the micro movement etc. The aim of this research is a development of surface modification method for the titanium implant to give a strong and prompt bone.There is a method of calling the alkali treatment to make one of the expected surface modification method extract a bone-like apatite layer directly to the surface of titanium. The material is soaked in a simulated body fluid, and the bioactivity of titanium is appreciable according to whether apatite precipitate on it.In this study, in order to fix a small amount of Ca to the surface of titanium beforehand, a hydro-thermal treatment was given at 200C by using 10mmol/L CaCl_2 solution paying attention to the generation mechanism of apatite in vivo. Pure Ti and the Ti alloy with this treatment showed that an initial attachment and a proliferation speed of the osteoblast cell gathered from rat's bone marrow were higher than those with the alkali treatment.The titanium implant with this treatment was implanted in rat's tibia bone and interface of bone and implant was observed. After implantation for 1 week, the bone contact rate of the titanium with this treatment indicated the more than 55% while the titanium with non-treatment indicated 5.7%. And that value reached about 100% after implantation for 4 weeks.From the above-mentioned result, it was suggested that the hydro-thermal treatment that used the CaCl_2 solution was a surface modification method giving bioactivity for titanium.