Evaluation of different self ligationg brackets in leveling vertically displaced canine using 3D FEA

Abstract

In this study, self-ligation brackets of active and passive type were bonded to canines which were vertically displaced at 1.0 mm, 2.0 mm and 3.0 mm superior to occlusal plane respectively, and metal bracket was bonded as control group. When initial orthodontic force was applied, stress at the tooth and its surrounding alveolar bone were observed from lateral, longitudinal and vertical direction. This study is to investigate on the differences of the stress distribution according to the type of self-ligation brackets and the differences from the metal bracket as the control group by comparing them using finite element analysis. At 1.0 mm above the occlusal plane, vertical stress was the largest in smart clip bracket, and then clippy-c bracket and metal bracket in order, and vertical displacement was the largest in smart clip bracket and the smallest in metal bracket proportionally to the stress. At 2.0 mm above the occlusal plane, vertical stress was the largest in clippy-c bracket, and then smart clip bracket and metal bracket in order, and vertical displacement showed the value proportional to the stress just as in the 1.0mm case. At 1.0 mm and 2.0 mm above the occlusal plane, self-ligation bracket was more advantageous than metal bracket because the vertical stress and vertical displacement of self-ligation bracket was large. At 3.0 mm above the occlusal plane, vertical stress was the largest in smart clip bracket, and then metal bracket and clippy-c bracket in order, and vertical displacement was the largest in smart clip and the smallest in clippy-c bracket proportionally to the vertical stress. At 3.0 mm above the occlusal plane, self-ligation bracket was not always more advantageous because the vertical displacement of clippy-c bracket was the smallest at 3.0 mm superior point. The size of vertical stress and vertical displacement were proportional to each other, and it was that more vertical movement was not always gained in self-ligation bracket and was depending on bracket system.