Effect of Zinc Oxide Nanoparticle Coating and Artificial Saliva on the Frictional Resistance of Self-Ligating Ceramic Brackets: An In Vitro Study

Aim: The objective of this research was to investigate how ZnO nanoparticles and artificial saliva influence the frictional resistance in self-ligating ceramic orthodontic brackets while performing sliding mechanics Materials & Methods : A total of sixty maxillary canine brackets were divided into three groups: uncoated self-ligating ceramic brackets, ZnO-coated brackets, and ZnOcoated brackets tested under artificial saliva. The friction produced by sliding was measured using a universal testing machine with a 0.019 × 0.025-inch stainless-steel archwire. One-way ANOVA was used for the statistical analysis, and p-values of ≤ 0.05 were considered significant. Results: The results showed a significant difference in the ZnO-coated brackets when compared to those of the uncoated brackets. The frictional value for the ZnO-coated brackets tested with artificial saliva was the lowest compared with the uncoated group. ZnO coating increased friction, whereas the addition of artificial saliva to the coated brackets reduced friction (p < 0.001). Conclusion: ZnO nanoparticle coatings increased the frictional resistance of selfligating ceramic brackets in a dry state. Artificial saliva significantly reduced friction, showing its effective lubricating role at the bracket–archwire interface.