Mechanical testing and finite element analysis of orthodontic teardrop loop

Abstract

Introduction: Understanding how teeth move in response to mechanical loads is an important aspect of orthodontic treatment. Treatment planning should include consideration of the appliances that will meet the desired loading of the teeth to result in optimized treatment outcomes. The purpose of this study was to evaluate the use of computer simulation to predict the force and the torsion obtained after the activation of teardrop loops of 3 heights. Methods: Seventy-five retraction loops were divided into 3 groups according to height (6, 7, and 8 mm). The loops were subjected to tensile load through displacements of 0.5, 1.0, 1.5, and 2.0 mm, and the resulting forces and torques were recorded. The loops were designed in a CAD software, and finite element analysis was performed with Ansys software (version 7.0, Swanson Analysis System, Canonsburg, Pa). Statistical analysis of the mechanical experiment results was obtained by ANOVA and the Tukey post-hoc test (P <.01). The correlation test and the paired t test (P <.05) were used to compare the computer simulation with the mechanical experiment. Results and Conclusions: The computer simulation accurately predicted the experimentally determined mechanical behavior of teardrop loops of different heights and should be considered an alternative for designing orthodontic appliances before treatment. © 2008 American Association of Orthodontists.