fa Optimization of unilateral molar rotation correction by a trans-palatal bar: a three-dimensional analysis using the finite element method ارتودنسی Orthodontics پژوهشي Research <p> <strong>Objective:</strong> </p><p> 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. </p><p> <strong>Design:</strong></p><p>  Three-dimensional analysis of different TPA designs was carried out using the finite element method. </p><p> <strong>Setting:</strong></p><p>  Department of Orthodontics, Tehran University of Medical Sciences, Iran. </p><p> <strong>Material and methods</strong>:</p><p>  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, moment and energy produced in the normal side (right) molar were recorded for each of the models. </p><p> <strong>Results:</strong></p><p>  Findings showed that in all designs, the associated mesializing force was lower than that seen in the traditional design and the moment showed an increasing pattern when compared with a simple palatal bar. Regarding energy levels, the same increasing pattern was observed in the designs between activations of 0·1 and 1·0 mm. </p><p> <strong>Conclusion:</strong> </p><p> According to our optimized system, the TPA design with the highest energy and moment, but the lowest mesializing force associated with derotating a maxillary molar tooth was a parallel wire II design (i.e. adding a straight wire). </p><hr><p></p><p> <strong>Source: </strong>Journal of Orthodontics</p><p> <a href="http://jorthod.maneyjournals.org/content/40/3/197.abstract" target="_blank"><font color="#0000ff">Full Text</font></a></p> Asymmetric activation, finite element method ,rotation transpalatal bar, unilateral 0 0 http://idai.ir/browse.php?a_code=A-10-32-1898&slc_lang=fa&sid=1 Allahyar Gerami gueramya@yahoo.com 10031947532846008899 10031947532846008899 Yes Orthodontics Department, Tehran University of Medical Sciences, Tehran, Iran Tahura Etezadi 10031947532846008900 10031947532846008900 No