Surface and Mechanical Properties of Different Coated Orthodontic Archwires

Objectives: The objective of this study was to evaluate the mechanical properties and surface characteristics of coated superelastic Ni–Ti archwires of three companies with different coatings before and after clinical use. Materials and Methods: Coated 0.016 inch mandibular archwires of three different companies with different coatings (G & H – epoxy coated on all sides, Rocky Mountain Orthodontics (RMO) – Teflon coated on labial surface, and American Orthodontics (AO) – Teflon coated on all sides) were used in this study. Twenty wires from each company, 10 as received and 10 retrieved from patients after 4 weeks of clinical use, were tested for load deflection and surface roughness. An independent sample t-test was done to compare surface roughness and load-deflection characteristics and one-way ANOVA analysis to compare between groups. Results: Both retrieved and as-received G & H wires showed less force levels during loading and unloading compared to RMO and AO wires (P < 0.05). In both test and control groups, G & H wires produced slightly higher surface roughness values compared to AO and RMO. In all the three company wires, roughness values increased significantly before and after clinical use. Conclusion: Retrieved coated archwires of all the three companies produced lower loading and unloading force values compared to as-received coated archwires. Surface roughness of coated archwires increased after use.