Finite Element Simulation of Displacement of the Broken Zygoma and Forces Exerted to the Complex After Fixation with Resorbable and Non-Resorbable One-Point Mini-Plates and Applying Normal or Severe Occlusal Loads

Background: ZMC fractures are the second most common trauma of the face. Therefore, their treatment (including methods of fixation) is of clinical significance. Objectives: Due to the lack of studies on many resorbable and non-resorbable fixations of the zygoma, this finite element analysis assessed for the first time displacements and dynamics of the zygoma fixed using three 1-point resorbable and three non-resorbable plates under normal and severe mastication forces. Methods: After creating the 3Dmodel of the zygoma and its adjacent bones based on a CT scan of amale patient, with linear fractures but without severe dislocations, three one-point resorbable and three similar one-point non-resorbable mini-plates were used to fix the zygoma with miniscrews. The zygomaticomaxillary buttress (ZMB), infraorbital rim, and frontozygomatic (FZ) suture were stabilized using L-shaped four-hole, curved five-hole, four-hole miniplates, respectively. The simulated zygoma was subjected to 150N and 750N loads. Minimum and maximum of stresses, strains, displacements, and rotational displacements of the zygoma were measured. Results: All four parameters were much smaller in non-resorbable fixations compared to resorbable ones. In severe maxillary force, the parameters stress, strain, and displacement increase considerably. Among these, FZ might cause smaller displacements. Resorbable plates might not be optimum choices for one-point fixation of cases with the heavy mastication loads.