Purpose: In Le Fort I osteotomy without using an osteotome (LF1-non-COSep), accidental fracture of the pterygoid process may occur in case of pterygomaxillary disjunction (PMD). Pterygoid process fracture is associated occasionally with severe hemorrhage. Therefore, it is important to predict unfavorable pterygoid process fracture. Previously, we reported that three-dimensional finite element analysis (3D-FEA) can fairly accurately predict the PMD pattern of LF1-non-COSep, and that simulation surgery using 3D-FEA could analyze and predict unfavorable pterygoid process fracture.
The aim of this study was to elucidate the technique of PMD to prevent an unfavorable pterygoid process fracture, using simulated surgery with 3D-FEA in LF1-non-COSep.
Materials and Methods: Computed tomography (CT) image data (100 sides) before LF1-non-COPSep were converted to the 3D-FEA analysis model. We simulated the PMD, and examined pterygoid process fracture from various angles of the cutting line in the maxillary lateral wall using 3D-FEA (occlusal plane model, line at 5 degrees to occlusal plane: +5° model, line at 10 degrees to occlusal plane: +10° model). The data were analyzed using Student's t-test, and differences were considered significant at P<0.05.
Results: The rate of pterygoid process fracture using 3D-FEA was 31% in the occlusal plane model, followed by the +10° model (18%) and +5° model (14%).
The incidence of pterygoid process fracture was higher in the occlusal plane model than the +5° model (odds ratio, 2.97; 95% CI, 1.45±6.36; P=0.002) and +10° model (odds ratio, 2.14; 95% CI, 1.09–4.34; P=0.02), respectively.
Conclusions: Simulated surgery using 3D-FEA provides useful information for selecting safer procedures in LF1-non-COPSep. In order to minimize the risk of pterygoid process fracture, a cutting line at 5 to 10 degrees to the occlusal plane in the maxillary lateral wall may be necessary.

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The purpose of this study was to evaluate the three-dimensional change of the lip morphology on lip closure and at smiling in patients with mandibular prognathism accompanied by mandibular deviation before and after surgical orthodontic treatment. Twelve patients (6 females, 6 males; age 31.3±13.2 years) were selected for this study. Frontal and lateral cephalograms and three-dimensional (3D) images were taken before and after the treatment. The inclusion criteria of used cases were as follows: 1) ANB angle smaller than 0°, 2) having negative overjet, 3) more than 5mm of lateral deviation between the mandibular midline (represented by Menton) and the facial midline, 4) less than 2° maxillary roll, 5) bilateral sagittal split ramus osteotomy performed, 6) normal SNA angle, and 7) without any congenital anomalies including cleft lip and/or palate.
Cephalometric analysis showed that the pre-treatment ANB angle was −1.92±1.18°, and the amount of deviation of Me was 8.16±2.83mm. The average setback movement of the mandible was 0.70±5.00mm on the deviated side and 8.61±2.84mm on the non-deviated side. The post-treatment ANB angle was 1.61±1.26°, and the post-treatment deviation of the Me was 1.58±1.80mm.
The 3D facial images showed that there was a clear difference in the positions between the left and right chelions at the time of lip closure and smiling at pre-treatment, and both chelions were almost symmetrically positioned at post-treatment. When comparing the 3D Cartesian coordinates between pre-and post-treatment, there were significant differences in chelion on the non-deviated side at the time of both lip closure and smiling. While the upper lip point moved inferiorly at the time of lip closure and smiling, the lower lip point showed remarkable changes, especially in the horizontal and anteroposterior directions.
The asymmetry of lower lip surface area at pre-treatment was corrected by surgical orthodontic treatment both at the time of lip closure and smiling at post-treatment. Lip asymmetry was corrected by surgical orthodontic treatment not only at the time of lip closure but also at smiling due to three-dimensional changes of the non-deviated side of the chelion.

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In the field of jaw deformities, there has been an increase in the number of middle-aged and elderly patients selecting surgical correction in recent years. However, treatment of these patients might be difficult because of poor oral condition such as edentulous jaws and tooth loss. Under these conditions, an interdisciplinary approach including orthodontics, oral surgery and prosthodontics is required for the treatment of jaw deformity. We report a patient with edentulous jaws who was treated with orthognathic surgery using the interdisciplinary approach.
The patient was a 42-year-old male diagnosed with mandibular protrusion. He was at risk of chronic diseases of the mouth, including dental infection and tooth loss. As a result of diagnosis of prosthodontics, all teeth were extracted to correct severe oral hygiene. Before corrective jaw surgery, wax dentures were made on the assumption of post-surgery oral condition. By using the wax dentures, dental implants were positioned on the edentulous jaws and provisional teeth were made. Regarding orthognathic surgery, intraoral vertical ramus osteotomy was performed on the right side of the mandible and sagittal split ramus osteotomy was performed on the left side. Twelve months later, osteotomy was performed and the final stage of prosthodontic treatment was started.
Following this interdisciplinary approach to jaw deformity treatment, the patient with edentulous jaws is satisfied with the stable occlusion and better facial contour.

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In this paper, we report a patient who developed angioedema of the face and pharynx after sagittal split ramus osteotomy, leading to suffocation.
The patient was a 29-year-old female. To treat mandibular retrusion, sagittal split ramus osteotomy and maxillomandibular fixation were performed under general anesthesia. The duration of surgery was 2 hours and 30 minutes, and the volume of blood loss was 50g. Swelling of the face and pharynx was observed from 2 hours after surgery, and the SpO₂ reduced, resulting in the loss of consciousness. The maxillomandibular fixation was released, and the airway was maintained using a nasal airway. After improvement of consciousness and vital signs, ICU management was performed. With respect to postoperative edema, IgE and C1 inhibitor tests were conducted, considering the possibility of allergy or hereditary angioedema. Negative reactions were observed, suggesting idiopathic or physical stimulus-related angioedema.

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