Based on the anatomic structure of a girl with class III skelet al malocclusion, a three-dimensional finite element biomechanical model of facial soft tissue was established. With the use of this model, three surgery plans of distraction osteogenesis, LeFort I, II, III maxillary complex advancement in the direction of functional occlusal plane, were simulated. As a result, the facial soft tissue deformation was predicted and the ratio of the facial location deformation to the free bone advancement was calculated. The facial shape after surgery could be viewed in 3D. In addition, the location of center of resistance was investigated when the free bone was protracted forward in the process of LeFort I maxillary complex advancement; it was located at a site about 30 mm posterior to the soft tissue A point. The research result indicates that three-dimensional finite element research on distraction osteogenesis can provide instruction for setting the suitable protraction point and direction of the protraction force in surgery, and by predicting the facial soft tissue deformation, it also can provide the surgeon and patient with information on the options and reference to the surgery plans.
Adolescent ; Cephalometry ; Computer Simulation ; Face ; diagnostic imaging ; pathology ; surgery ; Female ; Finite Element Analysis ; Humans ; Imaging, Three-Dimensional ; Malocclusion, Angle Class III ; diagnostic imaging ; pathology ; surgery ; Maxilla ; diagnostic imaging ; pathology ; surgery ; Models, Biological ; Osteogenesis, Distraction ; instrumentation ; Osteotomy ; Radiography