Evaluation of rotational control and forces generated during first-order archwire deflections: a comparison of self-ligating and conventional brackets

The purpose of this study was to compare the activation and deactivation forces generated during first-order archwire deflections when different sizes and types of NiTi wires are paired with conventional and self-ligating brackets (SLBs) and to evaluate the rotational control between these same archwire and bracket combinations. Four maxillary premolar SLBs (Damon 3MX, SmartClip, Carriere, and In-Ovation R) and one conventional twin bracket (Victory) were paired with seven archwires [0.014, 0.016, 0.018, 0.016 × 0.022 Ultra Therm (thermal A f 80-90°F), 0.016, 0.018 SPEED Supercable, and 0.017 × 0.025 Turbo]. A cantilever test design was used and 10 trials per bracket/archwire combination were performed. Load/deflection data were captured over 4 mm fi rst-order archwire deflections. Forces generated were compared across all bracket/archwire combinations. Among thermal archwires, for a given deflection, forces increased with increasing archwire size. Supercable archwires displayed less force than their same size thermal counterparts. The Turbo archwire generated force values in between those of 0.016 and 0.018 thermal archwires. Rotational control improved with increasing wire dimensions and for a given archwire size. Rotational control among brackets generally ranked as follows: In-Ovation R > SmartClip > Carriere and Damon 3MX.