Evaluation of friction on self-ligating and conventional brackets associated with different types of archwires submitted to sliding mechanics

Abstract

Aim: The aim of this study was to verify the frictional force during sliding mechanics in orthodontic tooth movement, using conventional metal brackets of the active and passive selfligating types with stainless steel and copper nickel titanium archwires. Methods: This experimental in vitro study was conducted with conventional metal (Morelli, Sorocaba, SP, Brazil) brackets, active self-ligated (SLI Morelli, Sorocaba, SP, Brazil) and passive self-ligated (SLP Morelli, Sorocaba, SP, Brazil), with slot 0.022 x 0.028 inches and Roth prescription. The brackets were tested with rectangular section 0.019 × 0.025 inch copper nickel titanium and stainless steel archwires. For each type of bracket, 10 sets of plate/bracket/archwire segment (n=10) were fabricated. Non-parametric Kruskal Wallis and Dunn tests were used for comparison between types of brackets and Wilcoxon tests for comparison between types of archwires. Results: The results showed that the frictional force values were higher with copper nickel titanium than with stainless steel archwires (p<0.05). When copper nickel titanium archwires were used, the active self-ligating brackets showed higher frictional force values than the other types, followed by the conventional brackets. Lower frictional force values were observed with passive selfligating brackets. For stainless steel archwires, no difference was observed between conventional and active self-ligating brackets, the passive self-ligating type presented lower frictional force values than the others. Conclusion: It was concluded that the higher frictional force was observed when active self-ligating brackets were associated with copper nickel titanium archwires. Lower frictional force was verified between passive self-ligating brackets combined with stainless steel archwires.