Effects of first- and second-order gable bends on the orthodontic load systems produced by T-loop archwires

Abstract

ABSTRACT Objective: To measure the effects of first- and second-order gable bends on the forces and moments produced by a commercially available closing T-loop archwire. Materials and Methods: A dentoform-simulated space closure case was mounted on an orthodontic force tester. Sixteen gable bend combinations were placed in the archwires, which were then activated using standard clinical procedures. At each activation, the three force components and three moment components on the maxillary left lateral incisor and canine were simultaneously measured. Results: The first- and second-order gable bends showed low load coupling effects when used independently, but the load systems became unpredictable when bends were combined. Gable bends affect the magnitudes and directions of the forces and moments that are applied to teeth. The resulting moment to force ratios are sensitive to the bends. Conclusion: Gable bends alter the orthodontic load systems; however, the three-dimensional interactions produce complex and unpredictable tradeoffs.