| Pure titanium and titanium alloys have been widely used as implant materials in dentistry currently. Although they have excellent mechanical characters and good biocompatibility, elastic modulus of titanium alloys is still greater than that of bone. The recent trend in research and development of titanium alloys for biomedical application is to develop low elastic modulusβtype titanium alloys composed of non-toxic and non-allergic elements with excellent mechanical properties. A new titanium alloy, Ti-24Nb-4Zr-7.9Sn (TNZS) which has lower elastic modulus and high strength, has been developed by Institute of Metal Research, Chinese Academy of Sciences. However, titanium and titanium alloys can not form chemical bonds with living bone. A method to solve the problem is to modify metallic surface. Anodic oxidation is a traditional technology of metallic surface treatment.Before a new material is intended for human use, biological evaluation plays a crucial role. The biological safety and biocompatibility of a material can be evaluated by in vitro and in vivo tests. In this study, the Structure and composition of TNZS alloy treated by anodic oxidation have been investigated, and its biological safety and biocompatibility have been evaluated by cell culture and animal experiments. It can provide theoretical basis for optimizing metal composition, improving technology of metallic surface treatment and clinical application.Objective:To evaluate the method and efficacy for TNZS modification by using anodic oxidation technology , and to access its biological safety and biocompatibility.Methods:1. The surface morphology was observed with SEM. The element distribution and composition of oxidation film were analyzed with EDS and XRD. The surface energy of oxidation film was analyzed with contact angle measuring instrument.2. According to the GB and YY-T, AD-TNZS was tested with the cytotoxicity test, in vitro hemolytic test, oral mucous membrane irritation test and acute general toxicity test.3. The osteoblasts were isolated from craniums of SD rats and inoculated onto specimens of AD-TNZS and pure titanium. Cell adherence, proliferation and ALP activity were examined. The morphology of the cells was observed by SEM.Results:1. The film was consisted of many micro porous, about of 0.1 to 5μm in diameter. The oxidation film was composed of Ti,Nb,Zr,Sn,O,Ca elements. The phases in the oxidation film were anatase and rutile TiO2.The surface energy of TNZS was increased after being anodic oxidized.2. The result of cytotoxicity test showed that the samples had no cytotoxicity. The result of in vitro hemolytic test showed that the hemolytic rates of all samples were lower than 5%. The result of oral mucous irritation test showed that all samples had no mucous membrane irritation. The result of acute general toxicity test showed that all samples had no acute general toxicity.3. AD-TNZS could accelerate the early adhesion of osteoblasts. In early period the proliferation and alkaline phosphatase activity of two groups were in a multilayer means. But they were significantly increased on AD-TNZS than that on pure titanium after 10 days'cell culture. SEM showed that osteoblasts on AD-TNZS spread well and adhered firmly. With the time increasing, the cells proliferated well and secreted matrix.Conclusion:Anodic oxidation technology can form an oxide film on TNZS which is consisted of micro porous with different diameters and enhances the surface energy; the new TNZS alloy after being anodic oxidized possesses good biological safety and biocompatibility. The adherence, proliferation and differentiation of osteoblasts are all improved. |
