Biomechanical Evaluation of Nano-Zirconia Coatings on Ti-6Al-7Nb Implant Screws in Rabbit Tibias / 华中科技大学学报（医学）（英德文版）

ABSTRACT

The clinical success of dental implants can be improved by achieving optimum implant properties,such as their biomechanical and surface characteristics.Nano-structured coatings can play an important role in improving the implant surface.The purpose of the present study was to determine the most appropriate conditions for electrophoretic deposition (EPD) of nano-zirconia coatings on Ti-6Al-7Nb substrates and to evaluate the structural and biomechanical characteristics of these deposited coatings on the dental implants.EPD was used with different applied voltages and time periods to obtain a uniform layer of nano-zirconia on Ti-6Al-7Nb samples.The coated samples were weighed and the thickness of the product layer was measured.Surface analysis was performed by using optical microscopical examination,scanning electron microscope and X-ray diffraction phase analysis.For in vivo examination,48 screw-designed implants (24 uncoated and 24 nano-zirconia coated) were implanted in both tibiae of 12 white New Zealand rabbits and evaluated biomechanically after 4-and 12-week healing intervals.Results revealed that the use of different conditions for EPD affected the final coating film properties.Increasing the applied voltage and coating time period increased the deposited nano-zirconia film thickness and weight.By selecting the appropriate coating conditions,and analyzing scanning electron microscopical examination and XRD patterns,this technique could produce a thin and continuous nano-zirconia layer with a uniform thickness of the Ti-6Al-7Nb samples.Mechanically,the nano-zirconia-coated implants showed a highly statistically significant difference in removal torque values,while histologically these coated implants enhanced and promoted osseointegration after 4 and 12 weeks of healing,compared with the uncoated ones.In conclusion,EPD is an effective technique for providing a high quality nano-zirconia coating film on dental implant surfaces.Moreover,the osseointegration of these coated dental implants is improved compared with that of uncoated ones.