Graphene oxide nanocoating for enhanced corrosion resistance, wear resistance and antibacterial activity of nickel-titanium shape memory alloy

For nickel-titanium (NiTi) shape memory alloy used in clinical orthodontic treatment, the corrosion media and bacteria in saliva increase its corrosion tendency; and the high surface frictional resistance limits the efficiency of teeth movement. Corrosion resistance, friction performance, and antibacterial properties of graphene oxide (GO) coatings on NiTi alloy were investigated as a function of the GO concentration. Compared with the NiTi substrate, GO coatings with different concentrations reduced the corrosion tendency in the artificial saliva, and enhanced the lubricity as well as anti -Streptococcus mutans ability. However, when the GO concentration was low, the corrosion resistance and friction resistance of the coating were insufficient; when the concentration was too high, cells cultured with the GO-coated NiTi were more susceptible to oxidative stress damage. This study provided a comprehensive assessment of nanometer-level GO coatings on NiTi alloys used in orthodontics, with the purpose of informing and guiding further detailed research to optimize the surface properties of GO-coated dental alloys.