The effect of ZnO nanopracticles deposition for friction reduction on orthodontic wires

Abstract

In the sliding technique, the reduced frictional forces between the wires and orthodontic brackets are associated with the rapid tooth movements and better control of the anchorage. Recently, wire coating with the different nanoparticles has been proposed to decrease the frictional forces and satisfactory results are also reported for it. The present study was done to coat the stainless steel wires with the ZnO fullerene-like nanoparticles and determine the effect of this coating on friction between the wires and orthodontic brackets in in vitro. Materials and Methods: In this in vitro experimental trial, stainless steel wires )0.0165,0.019 0.025)of the two 0.018 and 0.022 orthodontic bracket systems (n=20( were coated with zinc oxide nanoparticles by wire immersion in ethanol + Zno nano particle and the coated and uncoated wires analyzed by the SEM and XRD observations .SEM observations approved the nanoparticle coating of the wires. Kinetic friction between the wires and orthodontic brackets were calculated using universal testing machine. The frictional forces between the wires and the brackets were statistically analyzed using three-way ANOVA, one-way ANOVA, student t and Tukey multiple comparison tests. Results: Wire type, the angle between the bracket and wire as well as coating with ZnO nanoparticles significantly influenced the frictional force values (all: p<0.0001). In 0.019 0.025 wires, the friction forces were 1.690.18 and 3.440.32 N in the coated and uncoated wires (51% reductions). In the 0.016 wires, the friction values evaluated to be 1.560.11 and 2.560.34 N in the coated and uncoated conditions (39% reductions). Frictional values were significantly increased with the increased angles between the wire and bracket and also higher values of the friction were observed in the 0.018 bracket system than 0.022 brackets. Conclusion: Due to the positive effects of ZnO nanoparticle coating in the decreased friction between the wire and brackets, the technique can be used as an effective way to substantially reduce the friction during tooth movements with the subsequent better anchorage control.