| Objective:Osseointegration is widely accepted in clinical dentistry as the basis for dental implant success. Surface characteristics of implants such as surface morphology, hydrophilicity, chemical composition affect the osseointegration. TiO2nanotubes can significantly promote the growth of osteoblasts. Hydrophilic surface can induce the deposition of the mineralization. When implants come into contact with a biological environment, protein adsorption that occurs immediately will mediate subsequent cell attachment and proliferation. Before implantation in the human body, implants must be disinfected. Will the wettability and protein adsorption of TiO2nanotubes on the surface of titanium be affected by different sterilization methods? These contents haven’t been elaborated in previous studies in detail. Therefore, from the perspective of better osseointegration and implant success, the aims of our study are to fabrication of implant coatings of TiO2nanotubes and investigate the excellent sterilization method of implants so as to provide a theoretical basis for the clinical application of implants.Methods:Pure titanium sheets of15mm in diameter and thickness0.5mm were used as implant material. These titanium sheets were polished with SiC abrasive paper. The implants were rinsed in an ultrasonic bath of acetone, ethanol and distilled water respectively for10min. The polished titanium sheets were anodized under the voltage of20V. After that, the samples were sterilized with UV irradiation and autoclaving. Serum albumin which accounts for nearly one-half of plasma proteins is elected in our study. Protein solution (lmg. mL-1protein/phosphate buffered saline, PBS) was made. The adsorption behaviors of BSA onto the titanium nanotubes (TNTs) were investigated at37℃. The protein concentration was determined by combining UV-spectrophotometer measurement at278nm at10、30、45、60min、2、4、6、12and24h respectively. The samples were removed and washed three times using PBS and rinsed with water to remove non-adherent proteins and allowed to dry at room temperature. These samples were immersed in PBS at37℃. The release behaviors of BSA onto the TNTs were determined. The solutions which be tested were removed back into the original centrifuge tube in order to ensure that the volume of solution was unchanged. All data were analyzed using Independent-samples T Test.Results:1. Surface characterization of titania nanotubesSEM image shows that the TNTs using anodization voltage of20V for1h are uniform over the substrate, which has the pore size of approximately80nm and the thickness of the wall of TNTs approximately10nm. The polished titanium sheets have no nanostructure with only SiC sanding marks.2. The wettability of titania nanotubes after sterilizationThe contact angles of TNTs and polished titanium sheets sterilized with UV irradiation were smaller than that of titanium sheets sterilized with autoclaving.3. The effects of sterilization methods on the protein adsorption of TNTsThe adsorption capacity of BSA on the surface of TNTs sterilized with UV irradiation was super to that of sterilized with autoclaving. The adsorption capacity of BSA on the surface of TNTs was better than that on polished titanium sheets.4. The effects of sterilization methods on the release behaviors of protein on TNTsThe results show that the cumulative release rate of BSA on polished titanium sheets was higher than the nanotubes. The release experiment results also suggested that BSA release in the autoclaving group was faster than that in UV irradiation group.Conclusions:1. TiO2nanotubes with a tube diameter of80-100nm in a highly regular arrangement were achieved by anodizing Ti sheets under the voltage of20V.2. The adsorption capacity of BSA on TNTs and the wettability of TNTs sterilized with UV irradiation were super to that of sterilized with autoclaving. Therefore it is recommended that such implants are sterilized by UV irradiation in the future. |
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