A Biomechanical Assessment of three Types of Plating Systems in a Combined Mandibular Parasymphysis and Angle...

Mandibular fractures are the most encountered fractures by oral and maxillofacial surgeons, and for their fixation, different systems have been studied and used in clinical practice. Miniplates in lines of osteosynthesis described by Champy have stood the challenge of time for maxillofacial fractures. Many designs have been proposed since then. Three-dimensional (3D) plates, designed to have a geometric shape, claimed to add strength and stability to fracture fragments. Locking plates were designed to have screws that lock in the plate and thus provide added stability to fixation.

The aim of this study was to compare the efficacy of three internal fixation systems for osteosynthesis of combined angle and parasymphysis mandibular fractures. Fifteen sheep mandibles were used. Osteotomy simulating parasymphysis and contralateral angle fracture were done and fixed with three plating systems, 5 in each group. Group A with straight non-locking miniplates, Group B with 3D miniplates and Group C with locking miniplates. Universal Testing Machine was used to apply force ranging from 0 to 900 Newton (N) on the occlusal surface. The forces which caused significant displacement between fracture segments were recorded. The post hoc test showed significance between forces in the groups, i.e., P < 0.05.

Plates which least resisted displacement between fractured segments were straight non-locking miniplates with a mean end-point force of 109.20N, as compared to 3D plates, 327N and locking plates, 345.2.

Biomechanically, locking miniplates are more efficient than 3D miniplates which in turn are more efficient than non-locking miniplates in an in vitro scenario.