COMPARAÇÃO DA EXPRESSÃO DO TORQUE ENTRE BRAQUETES ESTÉTICOS

Abstract

This study aims to investigate torque expression in different types of esthetic conventional and self-ligating brackets using a 0,019”x0,025” rectangular stainless steel archwire. It was selected ten types of brackets from six different commercial brands: four ceramic self-ligating brackets (In-Ovation C – GAC, Damon Clear – Ormco, QuicKlear - Forestadent, Click-It - TP Orthodontics), one ceramic self-ligating bracket with metal-reinforced slot (Clarity SL - 3M Unitek), three ceramic conventional brackets (Inspire Ice – Ormco, InVu Ceramic - TP Orthodontics, Roth Ceramic - Morelli) and one ceramic conventional bracket with metal-reinforced slot (Clarity Metal-Reinforced Ceramic Bracket - 3M Unitek). As control it was used the metallic Damon MX self-ligating bracket (Ormco). It was used 50 0,019”x0,025” rectangular stainless steel archwire segments. Third-order moments were measures at 12º, 24º e 36º by the use of an archwire torsion device associated with a Universal Testing Machine (EMIC DL2000). For comparison of the third-order moment it was used the Anova and Tukey tests. In all tested angulations the Damon Clear bracket presented the highest third-order moment. It was followed by the Clarity, Clarity SL and Damon Mx brackets, and with the worst torque expression was the InVu Ceramic bracket. When it was observed the clinically effective torque this study showed that it started in smaller torsion angles in that brackets that have smaller slot heights and consequently smaller torque play between the archwire and the slot. Among them, the Damon Clear was the one that firstly presented a clinically effective torque, and the smallest slot height. The InVu Ceramic had the biggest slot height and was one of the latest to express a clinically effective torque. Some brackets broke during the tests not supporting all the torque applied. The QuicKlear bracket broke before 24° and Ceramic Roth and Click-it broke before 36°.