Finite Element Analysis of Two- and Three-Dimensional Fixation in Treating Mandibular Symphyseal Fracture Combined With Bilateral Condylar Intracapsular Fractures

The aim of this study was to compare through finite element analysis two- and three-dimensional (2D and 3D) fixation in the treatment of mandibular symphyseal fracture combined with bilateral condylar intracapsular fractures. The authors created 2 fixation models for the above fracture, and analyzed the stress and displacement in the mandible and fixation materials under 3 loading conditions. The von Mises stress of the mandible and plates peaked during lateral occlusion, and was lowest during central occlusion. In all conditions, stresses in the fixation materials did not exceed the yield stress of titanium. The inferior border of the symphyseal fracture segments showed opposing displacements, and the mandible tended to widen in the 2D fixation model. However, the fracture displacement did not exceed 150 mu m for either fixation method. The results suggested that after well reduction and fixation of condylar intracapsular fractures, either 2D or 3D fixation for symphyseal fracture can provide adequately strong fixation. Compared with 2D fixation, 3D fixation has more advantages in controlling the mandibular width and preventing the fixation materials from enduring excessive stress.