Novel cytotoxicity of nano-coated orthodontic micro-implants: An <i>in vitro</i> study

Objectives: Many attempts have been made to modify the surface of orthodontic micro-implants and prevent the development of microbes by coating them with antimicrobial nanoparticles (NPs). The purpose of the present study was to evaluate the cytotoxicity of different NPs, namely, TiO2 and zinc oxide (ZnO) NPs, that are used to coat titanium orthodontic micro-implants. Material and Methods: Thirty orthodontic micro-implants were included in this study. Those were divided into three groups: control group without coating, TiO2-coated orthodontic micro-implants, and TiO2- and ZnO-coated orthodontic micro-implants. Scanning electron microscope, energy-dispersive spectroscopy (EDS), and cytotoxicity tests were applied for all groups. Results: The results of scanning electron microscopy and EDS showed effective deposition of the titanium oxide layer onto the micro-implants. The ZnO layer applied on the micro-implants exhibited superior physicochemical characteristics in comparison to the uncoated samples with no significant cytotoxicity. Conclusion: Both NPs showed biocompatibility with the oral tissues.