Frictional Resistance of Non Coated and Epoxy Coated Superelastic NiTi Wires used for Aligning in Three Types of Brackets

Abstract

Introduction: Coated archwires are preferred in combination with aesthetic orthodontic brackets by orthodontists over non metallic aesthetic archwires. Studies evaluating the frictional properties of epoxy coated round superelastic Nickel Titanium (NiTi) archwires are limited to stainless steel brackets. Aim: To evaluate and compare the frictional resistance of an epoxy coated 0.016" superelastic NiTi archwire in stainless steel, composite and ceramic brackets and to compare it with the frictional resistance generated by non coated 0.016" superelastic NiTi archwire in same brackets. Materials and Methods: An in-vitro experimental study was conducted in the Department of Orthodontics at SRM Dental College from January to February 2020. Frictional resistance of 30 epoxy coated aesthetic 0.016" upper superelastic NiTi wires (G4™ Nickel Titanium, 0.016, Upper Trueform™ I, ToothColored) and 30 conventional 0.016" upper superelastic NiTi wires (G4™ Nickel Titanium, 0.016, Upper Trueform™) from G&H® orthodontics while sliding across three different types of brackets were evaluated. Twenty stainless-steel (Gemini® 3M unitek, Monrovia, California), 20 composite (FLI® RMO, Denver, Colo.), and 20 gemini clear ceramic (Gemini clear ® 3M unitek, Monrovia, California) 0.022x0.028" Slot Roth prescription maxillary first premolar brackets were used. The brackets and archwires were divided into six groups of different bracket and archwire combination with 10 samples in each. An Instron testing machine with a 10 N tension was used to measure the frictional resistance. The obtained values were analysed using One-way ANOVA and followed by Post Hoc Tukey HSD for multiple comparison. Results: Coated wires generated significantly high friction in ceramic brackets (136.90±3.79 gms) followed by composite brackets (125.66±3.44 gms) and stainless steel brackets (92.53±8.70 gms). Non non coated wires generated significantly high friction with ceramic brackets (89.60±2.90 gms) whereas the friction generated in composite (70.87±5.79 gms) and stainless steel brackets (67.70±2.80 gms) was not significantly different. Conclusion: Epoxy coating increased the frictional resistance generated by the 0.016 superelastic NiTi archwires irrespective of bracket materials. The coated wires generated less friction in composite brackets compared to ceramic brackets. Further clinical trial are recommended to evaluate the aligning efficacy of these archwires in aesthetic brackets.