Optimization of unilateral molar rotation correction by a trans-palatal bar: a three-dimensional analysis using the finite element method

AbstractObjective: The main goal of this study was to optimize unilateral molar rotation correction by modifying a trans-palatal arch (TPA) design using the finite element method.Design: Three-dimensional analysis of different TPA designs was carried out using the finite element method.Setting: Department of Orthodontics, Tehran University of Medical Sciences, Iran.Material and methods: For this investigation, 13 three-dimensional finite element models were produced for different TPA designs without pre-activation bends. Each model contained a palatal bar and two tubes. Optimizing unilateral molar rotations was achieved by five separate different paths: incorporating U-loop(s), ‘R’ loop(s) or helix/helices, a reverse action of the helix/helices and adding a straight wire to the design. The mesial part of the left side tube was displaced 0·1, 0·25, 0·5 and 1 mm, successively towards the midline, simulating palatal bar tab engagement in a mesio-palatal rotated maxillary left molar. The mesio-distal force, m...