A Three Dimensional Analysis of Reconstruction Plates Used in Different Mandibular Defects

In this study, the reasons of breaking of the reconstruction plates used in mandibular continuity or mandibular defects were investigated. The study was conducted on 3 cases in which reconstruction plates were used for tumor resection or invasive wound. The objective was to evaluate the mechanical stress in reconstruction plates by means of the finite element method. Three dimensional model of reconstruction plate was exposed to chewing force. A commercial finite element solver (ANSYS) was then applied to this plate to compute the stresses generated in chewing situation. Stress analyses have been carried out by applying Von Mises Yielding Criteria. In the standard reconstruction plate, the results of the finite element analysis revealed that stress resulting from the simulated functional loadings which far exceeded the strengths of the components. The main application of this study was the prediction of fractures as a consequence of known forces. If it was assumed that the patient executes several thousand masticatory movements within a week, a dynamic strain would be present due to the large number of changes in loading, so that there was a danger of a fatigue fracture at the point of the stress concentration (as seen in the analysis), as is also confirmed by clinical practice.