A biomechanical analysis of titanium miniplates used for treatment of mandibular symphyseal fractures with the finite element method.

OBJECTIVE: This study aimed to evaluate the stress distribution and stress shielding effect of titanium miniplates used for the treatment of symphyseal fractures using finite element (FE) analysis.

STUDY DESIGN: Two 3-D FE models of symphyseal fractured mandibles reduced by technique 1, reduction with a single miniplate, and technique 2, reduction with 2 miniplates, respectively, were developed. Three basic loading conditions were simulated.

RESULTS: The ratios of stress shielding of miniplates were different. Ratios of the lower miniplates in technique 2 were much higher than the upper miniplates and the miniplates in technique 1 during all conditions, and that value of the lower miniplate gained a maximum value of 83.34% during left unilateral molar clenching. The stress areas were concentrated on the central section of the miniplates. However, the stress distribution varied with masticatory conditions.

CONCLUSION: The study demonstrated that miniplate stress distribution and stress shielding effect ratio were affected not only by the way in which the mandible was loaded but also by the number of the miniplates fixing the fracture.