The effect of ZnO nanoparticles deposition for friction reduction on orthodontic wires and ceramic brackets

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. The friction between porcelain brackets and orthodontic wires is higher than other brackets. 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 and porclain brackes with the ZnO nanoparticles and determine the effect of this coating on the friction between the orthodontic wires and porcelain brackets in in vitro. Materials and Methods In this in vitro experimental trial one hundred twenty 0.019 0.025 stainless steel orthodontic wires with and without ZnO nanoparticles were used in 120 orthodontic porcelain brackets (0.022 slot) with and without ZnO nanoparticles .ZnO coating was applied with emersion in ethanol solution containing ZnO spherical nano particles.Coated wires and brackets were analyzed by the SEM observations .SEM observations approved the nanoparticle coating of the wires. Frictional force between the wires and orthodontic brackets were calculated using universal testing machine.the normal disturbution of results was tested with Kolmogrov-Smirnov and accordingly Kruskall-Wallis and Mann-Whitney tests were attepted. Results In combination of uncoated 19 25 wires-uncoated porcelain brackets the mean friction forces was 2.59 ( .3)N . In combination of uncoated wires-coated porcelain brackets the mean friction forces was 2.18 (.5)N . In combination of coated wires-uncoated porcelain brackets the mean friction forces was 2.54( .3) N and In combination of coated wires-coated porcelain brackets the mean friction forces was 3.07 ( .4)N .The resistance to sliding was significantly higher in coated wires-coated porcelain brackets than other groups. in uncoated wires-coated porcelain brackets group ,the resistance to sliding was significantly lower than other groups .there was no significant difference beween uncoated wires-coated porcelain brackets group and uncoated wires-uncoated porcelain brackets group . Conclusion Due to the positive effects of ZnO nanoparticle coating in the decreased friction between the wire and porcelain brackets, the technique can be used as an effective way to substantially reduce the friction during tooth movements with the subsequent better anchorage control, and decreased treatment times and root resorption risk