An In Vitro Evaluation of Frictional Characteristics of Labial and Lingual Self-ligating Brackets with Various Archwire Alloys

Abstract

Background: An understanding of bracket slot–archwire interface is imperative for biomechanical effectiveness in orthodontic sliding mechanics and hence the aim of the study is to evaluate frictional properties of lingual self-ligating brackets comparing with conventional lingual and labial self-ligating brackets using three different archwire alloys in various environments. Materials and Methods: This in vitro study compared the frictional force of labial and lingual self-ligating and conventional lingual brackets with stainless steel, TMA, and Cr-Co alloy archwires of 0.017” × 0.025” dimension in dry and wet conditions. Frictional forces were evaluated in a simulated half arch fixed appliance using a testing machine. Static and kinetic friction were measured and analyzed by one-way analysis of variance (ANNOVA) test and post hoc Duncan multiple range test. The effects of brackets and archwires in dry and wet conditions were analyzed by three-way variance (ANNOVA) test. Result: The maximum frictional forces were observed with labial self-ligating brackets followed by lingual conventional brackets and the least by lingual self-ligating brackets. Of all the wires tested, TMA wires had the maximum frictional forces followed by Co-Cr and stainless steel. In both conditions, the values were non-significant with all bracket–wire combinations except with Co-Cr and TMA wires. Conclusions: Varied amount of frictional force was shown by the brackets and wires with highest by labial self-ligating bracket, followed by lingual conventional and lingual self-ligating brackets. TMA wires experienced higher friction followed by Co-Cr and stainless steel with minimum friction.