Biomechanical assessment of ten fixation techniques after sagittal split ramus osteotomy for significant mandibular...

This study aimed to biomechanically evaluate ten different fixation methods following SSRO, simulating a 10mm mandibular advancement, with variations in plate position, angulation, and the use of bicortical screws.

Fifty polyurethane hemimandibles were randomly assigned to ten groups (n=5). SSRO was performed and stabilized using different configurations of 2.0mm plates and screws. Fixation methods included monocortical plates in varying angulations and positions, dual-plate systems, and hybrid techniques incorporating bicortical screws. All specimens underwent three-point compression testing using a universal testing machine. Peak compressive force and displacement were recorded.

The best biomechanical performance was observed in the group using two straight plates placed laterally at a +20° angle (Group 5). Groups employing hybrid or dual-plate systems performed significantly better than those using a single plate. Bicortical screws reduced horizontal displacement but were less effective alone in resisting vertical compressive forces.

Dual-plate fixation with specific angulation improves resistance to compressive forces in large mandibular advancements. The use of a single plate is not recommended unless combined with bicortical screw support.