Biosafety Of A Newly Developed Ti-based Alloy For Dental Implant

The development of dental implants has taken place for many years in an effort to create an optimal interaction between the body and the implanted material. The goal of achieving an optimal bone-implant interface has been approached by the alteration of implant,surface topography, chemistry, energy and charge as well as bulk material composition. Some researches define an ideal bone implant material as having a biocompatible chemical composition to avoid adverse tissue reaction, excellent corrosion resistance and mechanical compatibility to minimize bone resorption around the implant.While the ISO-10993-3-2009 and ISO10993-5-2009 criteria formulated that medical materials which would stay within the body for longer than 30 days must be evaluated for their genotoxicity and cytotoxicity. In order to evaluate the clinical feasibility for this kind of material as dental implant, the genotoxicity and cytotoxicity test seemed to be necessary. In this work, we examined the biosafty of the newly developed Ti-based alloy contained Zr,Ta,Nb using the in vivo and in vitro methods, respectively. Methods:The titanium disk we used in this research is offered by South China University of Technology. The extract was obtained according to standardized procedures and recommendations(ISO 10993-12). The CCK-8 assay was applied to evaluate the cytotoxicity of each group,while SCGE test used to evaluate the genotoxicity for each group. The systemic toxicity was performed and local effect after implantation was tested. and The data collected were measured by SPSS software for statistic analysis. Result:1.CCK-8 result: None of these functionalized groups were displayed of cytotoxicity potential, and the proliferation of the osteoblasts on the surface of each experimental group was not inherited compared with the pure titanium.2. SCGE result: All three SCGE parameters for each functionalized group displayed significant differences with the pure titanium, the result indicated that compared with the pure titanium group, the Ti-alloy disks would not lead to more DNA damage3. Local effect after implantation test: In the macroscopic assessment no animal has shown signs of ill health or reactions to the implant,no adverse tissue reaction was observed, in the microscopic assessment, the group of new Ti-alloy contains Si was obersived with some vascularisation and inflammatory cells infiltration.4. Acute systemic toxicity result: none of the animals treated with the test sample shows a significantly greater biological reactivity than animals treated with the vehicle control,and no animals shows decrease in body weight. Conclusion:1.New Ti alloy has got no cytotoxicity towards osteoblasts, and this treated surface would not restrain the proliferation of the osteoblasts;2.New Ti alloy would not lead to more DNA damage to the osteoblasts than the cleaned and polished pure titanium does;3.New Ti alloy would not lead to more tissue reaction than the pure titanium does.4.New Ti alloy shows no acute systemic toxicityThis thesis indicated the New Ti alloy was of no cytotoxicity and genotoxicity, acute systemic toxicity and local effect after implantation, this kind of Ti alloy would have a profound biological safety, and our test showed that this kind of Ti alloy could be feasible for future clinical application, and provided a theoretical support for that.