Elucidation of Factors Affecting Morphological Changes in the Alveolar Region of the Mandible Associated with Surgical Orthodontic Treatment

抄録

　　We used cone beam computed tomography data at the time of orthodontic treatment planning (T1) and at the completion of preoperative orthodontic treatment (T2) to quantify the changes in the morphology of the mandibular symphysis and elucidate the relevant factors. Additionally, using three-dimensional finite element analysis model (3D-FEM), we aimed to verify the mechanical behavior of the mandibular symphysis when applying orthodontic force to the mandibular anterior teeth.
　　This study included 45 patients with skeletal mandibular prognathism. The following six angles were evaluated in the measured areas: FMA, ANB angle, gonial angle, Y-axis angle, IMPA at T1 and only IMPA at T2. The distance of the measurement indicated the amount of change in bone morphology. In 3D-FEM, orthodontic force was added as the weight, and the stress distribution was calculated.
　　Statistical analysis suggested that the FMA, IMPA change, treatment period, and ANB angle affected the morphological changes. Additionally, no changes in the bone morphology were observed near the base of the mandibular symphysis, and the 3D-FEM yielded the same results.
　　In conclusion, changes in the bone morphology caused by surgical orthodontic treatment are limited to the area surrounding the roots of the teeth.