Effect of coating NiTi wires with spherical Zno nanoparticles on friction reduction

Abstract

NiTi wires which are considered the ideal alloys used during the alignment and leveling stage of comprehensive orthodontic treatment exhibit very high frictional resistance. Coating the wires with nanoparticles has been introduced to decrease resistance to sliding. The aim of this invitro study was to evaluate the effect of ZnO nanoparticles on resistance to sliding of nickel titanium orthodontic wires. Materials and methods: 120 straight pieces of 0.016-inch NiTi wires (OrthoTechnology,USA) were evaluated in two groups with and without spherical ZnO nanoparticle coating, along with 120 standard edgewise 0.018 inch stainless steel brackets (Ultratrimm,Dentaurum,Germany). ZnO nanoparticles were deposited on NiTi wires and analyzed by Scanning Electron Microscopy. A universal testing machine was used to determine friction between the wires and brackets at three angles of 0, 5 and 10. One-way ANOVA, StudentEs t-test and Tukey tests were used for data analysis. Results: The means of frictional forces with and without wire coating were 1.250.15 and 1.520.16 N, respectively, indicating a statistically significant decrease of 17.26% in friction in ZnO-coated wires The means of frictional forces after coating the wires with ZnO nanoparticles decreased significantly up to 13.09%, 17.24% and 20.84% at 0, 5 and 10 angles, respectively. Conclusion: Based on the results of this study, ZnO nanoparticle coating reduces the resistance to sliding of nickel titanium orthodontic wires.