Estudo das variações de ancoragem do aparelho de hyrax em expansão cirúrgica de maxila : análise por elementos finitos

Abstract

It is known that a suitable transverse maxillary dimension is a key factor for a stable occlusion, bringing functional and aesthetic benefits for the patient. In patients who present maxillary atresia and the end of bone growth, the best option for correction is said to be the surgically assisted rapid maxillary expansion (SARME). Several devices to assist the SARME have been described, and the most widely used is the Hyrax apparatus. The objective of this study was to evaluate, through finite element analysis, the anchorage variation of the Hyrax apparatus in SARME, thus seeking the option that presented greater orthopedic function and lower undesired effects. Five groups were created, each with a different dental anchorage, and the same force was applied to the expander screw. The displacement results (X, Y and Z axes) and stress were analyzed using a color scale. All groups presented bone displacement, with group 4 (anchorage in the 1st and 2nd molars) the group with the greatest horizontal displacement (X axis) and lower dental vestibularization, suggesting that variations in dental anchorage might affect the final treatment outcome.