Comparative Evaluation of Stability of Rigid and Non-Rigid Fixation in Bifocal Fractures of Mandible Involving a Unilateral Mandibular Subcondyle Fracture Associated with a Contralateral Mandibular Dentate Fracture: A Finite Element Analysis.

Introduction: Fixation of bifocal fractures of the mandible remains an enigma for surgeons as to how much fixation would be able to provide adequate stability. Increasing number of miniplates could lead to more complications. Thus, the aim of the study was to evaluate to minimum amount of fixation required to achieve adequate stability in bifocal fracturees of the mandible. Materials and Methods: The study was carried out in the Department of Oral & Maxillofacial Surgery and the Department of Mechanical Engineering using a finite element analysis. The Von Mises stresses and deformation distribution was analyzed when the mandibular subcondylar fracture and the contralateral parasymphysis or body fracture was fixed using a single or two miniplates. Forces were applied on the incisors, left and right molars. Results: The results revealed that the mandibular parasymphysis or body fracture with a contralateral mandibular subcondyle fracture showed adequate stability when fixed using a single four-hole with gap titanium miniplate for fixation of both fractures in combination with an arch bar (Von Mises stress on mandible = 555.59 MPa, 558.62 MPa on 150 N incisor load; 545.98 MPa, 545.24 MPa on 300 N left molar load; and 612.99 MPa, 652.85 MPa on 300 N right molar load). Conclusion: Non-rigid fixation is sufficient to provide adequate stability for bifocal fractures of the mandible involving unilateral mandibular subcondyle with associated contralateral mandibular dentate fracture.