On the effects of locking and non-locking screws in the mandibular fracture treatment: a finite element analysis

The utilization of a plate-screw system is a prevalent osteosynthesis technique widely employed for the fixation of mandibular fractures. While comparable findings exist regarding the impact of using locking and non-locking screws on the mandibular bone, conflicting results have been reported concerning their effect on stress distribution in the plate and screws. This study investigates the influence of locking and non-locking plate-screw systems on mandibular fracture fixation using finite element analysis, incorporating a 3D scanned jawbone geometry. Results indicate that locking screws exhibit a more uniform stress distribution while experiencing higher stress values compared to non-locking screws. Furthermore, the maximum stress in non-locking plates is lower than that in locking plates. In fact, replacing the locking screws with non-locking ones reduces the maximum stress in the plate by 62.5% and in the screw by 8.8%, respectively. Considering displacement in screws, findings indicate that the superiority of locking or non-locking screws depends on their location relative to the fracture.