Biomechanical study on monocortical osteosynthesis for the fracture of the mandible.

In order to compare the rigidity of the fixation and resultant bone healing of monocortical versus bicortical osteosynthesis, biomechanical tests were performed in dogs. Use of a gnathotome made it possible to produce a mandibular fracture with minimal bone defect between fragments. An AO dynamic compression plate and a mini-plate were used for the fixation of each half side of the fractured mandible. The biomechanical tests revealed that bicortical osteosynthesis was superior to monocortical in the rigidity of the fixation. However, the results after removal of the plates, at 14 weeks postoperatively, showed that there was no apparent difference between the 2 sides. Monocortical osteosynthesis is useful in the treatment of mandibular fractures, except for fractures with bone defects, comminuted fragments and laceration of the lateral cortical bone.