[Establishment and primary analysis of the three-dimensional finite element model of mandibular bilateral sagittal split ramus osteotomy with rigid internal fixation].

Objective: Establish the three-dimensional finite element models of mandibular bilateral sagittal split ramus osteotomy (BSSRO) with rigid internal fixation (RIF), for further study of BSSRO.

Methods: CT scanned technology and the finite element software (ANSYS) were used to establish the original three-dimensional model of mandible, modify the model to animate the BSSRO, then establish the model of RIF, last mesh the model to establish the finite element model of BSSRO with RIF. Apply 100 N occlusion force at the central incisor; calculate the stress distribution of the mandible and the RIF.

Results: Three-dimensional finite element models of BSSRO with RIF were established, such as miniplate model, bicortical fixation screw model. When biting with the incisor and fixed with upper plate, the stress of the medial screw position of the distal and medial segment of mandible is high. When fixed with bicortical fixation screw, the highest stress position located at the internal surface of the medial screw' s position of the distal segment of mandible.

Conclusions: The mentioned methods proved feasible in establishing the finite element models of BSSRO with RIF . The models can be applied to the study of BSSRO with RIF.