Análise biomecânica de diferentes tipos de fixação em osteotomia sagital do ramo após diferentes avanços e alterações do plano mandibular: um estudo com elementos finitos

Abstract

The aim of the present paper was to evaluate, via a finite element analysis, the tensions on the cortical bone and the plating system, as to evaluate mandibular resistance after the sagittal split ramus osteotomy with different mandibular advancements and mandibular plane movements. 3D mandibular models were obtained and a 6mm and 12mm advancement was planned associated with linear, clockwise or counter clockwise rotation of the mandibular plane angle. Each model was then fixed with one or two plates of the 2.0mm system and held with 4 monocortical screws at each side. A total of 12 models were built and they were subjected to a vertical load in the incisors region ranging from 50N to 500N in 50N increments. Results have shown that the 12mm advancement was associated with a higher tension in the cortical bone and plate surface. It was also concluded that the models fixed with 2 plates presented lower values of tension on the plates in comparison with the models fixed with a single plate. Counter clockwise rotation of the mandibular plane angle in the 6mm advancement, fixed with 1 or 2 plates, brought more tension to the plates, which did not occur in the 12mm advancements. These results may aid surgeons with decision making on a daily basis.