Avaliação de técnicas de fixação interna estável em dois desenhos de osteotomias dos ramos mandibulares: análise de elementos finitos

Abstract

PURPOSE: To evaluate and compare, using three-dimensional analysis of finite elements, two techniques of stable internal fixation in two drawings of sagittal osteotomy of the mandibular rami, as well as preparing two reports outlining the techniques and the repercussions of occlusal forces in the postoperative period through. METHODS: A three-dimensional finite element model of a hemimandible was created, with the design of two types of sagittal osteotomies of the mandibular rami with two different fixation techniques: a titanium miniplate of the Arnett system (1mm) for orthognathic surgery and four monocortical screws and a hybrid technique (plate fixed with monocortical screws and bicortical screw). A fixed vertical load of 200N was applied to the region of the occlusal surface of the lower first molar and of 100N to the incisal surface of the central incisor. RESULTS: There was a difference in the displacement of the set, which displaces in a much more accentuated way when there is no bicortical over the model without screw. However, it is clear that the model with short cut presents smaller displacements, when compared to the conventional cut. For metallic components, the low cut shows lower strain values, although the difference is not as pronounced. CONCLUSION: The hybrid technique, using 2.0 mm bicortical screws, proved to be more rigid and registered lower stress values both in the bone and in the plate, less deformation and displacements in comparison with the use of only a titanium miniplate of Arnett system (1.0mm) for orthognathic surgery and four monocortical screws for all mandibular movements and forces.