Study Of Antibacterial Activity Of TiO₂Nanotubes Coatings On Dental Implant By UV Photocatalysis

Dental implants have been an important technique for repairing missing teeth,butpotential complications like peri-implantitis leading the failure of dental implants.Researchers have studied different kinds of surface modification to improve the implantsantibacterial ability. Ultraviolet light （UV） irradiate TiO2occur photocatalytic reactionwhich can decompose organism. Anodization is one of the electrochemicaltechnique,which can fabricate nanostructure with better bioactivity on titaniumsurface.Based on the previous researches,this study used UV irradiate the TiO2nanotubescoatings which fabricated by andozation,evaluate the antibacterial ability ofStaphylococcus aureus （Sa） and Actinobacillus actinomycetemcomitans （Aa） afterphotocatalysis.Using contact angle measuring system to evaluate the hydrophilicity ofthe samples; using field emission scanning electron microscopy （FE-SEM） observe thesamples and the morphologies of bacteria; using confocal laser scanning microscopy （CLSM）to investigate the adhesion and membrane integrity of bacterial.The results:1. Titanium disks after anodization treatment can fabricated TiO₂nanotubes coatings.Different voltages have different diameters. The surface morphology of PT andnanotubes did not change before and after UV irradiation. UV irradiation can causecontact angles became smaller and increase the surface free energy.,which are relatedwith irradiate hours.2. After UV irradiation24hours，20V nanotubes coatings had smallest numbers of Sathan others.FE-SEM images showed that the morphology of Sa on TiO₂nanotubescoating fell apart,shrunk and died,the morphology of Sa were the most damaged on20V nanotubes coatings. The images by analysis of bacteria fluorescence intensityshowed that after UV irradiation, the content of bacterias on nanotubes coatings weremostiy dead（red）, What’s more, TiO₂nanotubes coatings after UV irradiation haslarger FIt value than PT,20V nanotubes coatings after UV irradiation has the largestFIr/FIg value.3. After UV irradiation24hours，10V nanotubes coatings had smallest numbers of Aathan others.FE-SEM images showed that the morphology of Aa on TiO₂nanotubescoating fell apart,shrunk and died,the morphology of Aa were the most damaged on10V nanotubes coatings. The images by analysis of bacteria fluorescence intensityshowed that after UV irradiation, the content of bacterias on TiO₂nanotubes coatingswere mostly dead, What’s more, TiO₂nanotubes coatings after UV irradiation haslarger FIt value than PT,10V nanotubes coatings after UV irradiation has the largestFIr/FIg value.4. UV irradiation different hours can kill Sa on20V nanotubes coatings,20V nanotubescoatings after UV irradiation has smaller numbers of Sa than PT as long as theirradiate hour more than4hours. FE-SEM images showed that the morphology of Saon nanotubes coating fell apart,shrunk and died. The images by analysis of bacteriafluorescence intensity showed that after UV irradiate the content of bacterias on20Vnanotubes coatings were mostly dead as long as the irradiate hour more than4hours, What’s more,20V nanotubes coatings after UV irradiation has larger FIt value than PT,there is no difference in FIr/FIg value of20V nanotubes coatings between threedifferent UV irradiation hours（4h,15h,24h）.5. UV irradiation different hours can kill Aa on10V nanotubes coatings,10V nanotubescoatings after UV irradiation has smaller numbers of Aa than PT as long as theirradiate hour more than4hours. FE-SEM images showed that the morphology of Aaon nanotubes coating fell apart,shrunk and died. The images by analysis of bacteriafluorescence intensity showed that after UV irradiate the content of bacterias on10Vnanotubes coatings were mostly dead as long as the irradiate hour more than4hours,What’s more,10V nanotubes coatings after UV irradiation has larger FIt value thanPT,there is no difference in FIr/FIg value of10V nanotubes coatings between threedifferent UV irradiation hours（4h,15h,24h）.Conclusion: UV irradiation can improve the hydrophilicity of PT and TiO₂nanotubescoatings, which is related with irradiate hours. After UV irradiation24hours,20V grouphas the best antibacterial ability of Sa,while10V group has the best antibacterial ability ofAa,.UV irradiation can improve the antibacterial ability of Sa on20V nanotubes coatingsand Aa on10V nanotubes coatings as long as the irradiate hour more than4hours.