Effects of the closing and opening muscle groups on jaw condyle biomechanics after prominent mandibular angle osteotomy

The aim of this study was to determine the effect of closing and opening muscle groups of the jaw on mandibular stability after prominent mandibular angle osteotomy, through three-dimensional finite element analysis (FEA).Six patients with prominent mandibular angles, without malocclusion, were selected as finite element models of preoperative and postoperative prominent mandibular angle surgery. Computed tomographic (CT) scans were undertaken of the patients before and after surgery and three-dimensional images reconstructed using Simpleware software. The images were imported into an FEA software. Boundary-constrained and load conditions were applied. The solution process was run, and actions of closing and opening muscle groups were simulated and calculated.The Von Mises stresses on the condyle position after the operation were higher than those before the operation. A significant difference was found between the stress distributions in the condyle position between prominent mandibular angle patients and mandibular angle ostectomy patients (P < 0.05).After osteotomy, the variation in force exerted by the closing and opening muscle groups of the jaw is one of the major factors affecting mandibular stability. FEA is a promising strategy in pre-surgical planning for improving surgical success and reducing complications.