Le FortⅠ osteotomy is one of the main methods in orthognathic surgery and allows movement in various directions. Superior repositioning of the maxilla is often required when treating maxillofacial deformities with vertical maxillary excess, for example in cases of long face or open bite, and protrusion of the menton. To be reliable and useful for accuracy and postoperative stability, horse-shoe osteotomy combined with Le FortⅠ osteotomy is often performed. However, when the distance between the palatine root apex of the maxillary molar tooth and the nasal cavity bottom is small, horse-shoe osteotomy cannot be performed due to the possibility of damaging the roots of teeth. In addition, if horse-shoe osteotomy is performed, superior repositioning becomes difficult due to strong bone interference depending on the width and inclination of the maxillary bone. The purpose of this study was to comprehend the tendency in the form of the maxillary bone of patients with facial deformity. The subjects were 274 patients who underwent surgery for facial deformity in our department for five years from April 2011 to March 2016. The measurement items were the distance between the palatine root apex of the maxillary first molar （6） and second molar （7） and the nasal cavity bottom, and the width and angle of inclination of the palatal side of the dentoalveolar part of the maxillary bone in coronal CT images. The results showed that the distributions of the distance, width, and angle of inclination were wide. The average value of root apex of 6 and the distance to the nasal cavity bottom was 9.68 mm and root apex root of 7 was 10.20mm. The median value of the thickness of the maxillary bone was 2.46mm （6） and 2.21mm （7）. The average value of the angle of inclination of the maxillary bones was 38.9 degrees （6） and 32.3 degrees （7）. Considering the distance between the root apex and the nasal cavity bottom of more than 6.0mm, and the thickness and inclination of the maxillary bone, 25.2％ of all cases were suitable and safe for horse-shoe osteotomy. In addition, about half of cases with facial asymmetry had a difference between the right and left in the distance between the root apex and the nasal cavity bottom. It is important to confirm the shape of the maxillary bone.

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A clinical analysis was performed on 148 patients who underwent orthognathic surgery at the Department of Oral and Maxillofacial Surgery, Nara Medical University for the 15 years from 2002 to 2016. The patients were 51 males and 97 females. Their ages ranged from 16 to 41 years old. The patients less than 25 years old accounted for 64.9％. Mandibular protrusion was the most common clinical diagnosis, made in 84 patients, followed by mandibular protrusion with asymmetry and/or open bite in 31 patients, and facial asymmetry in 16 patients. Le Fort Ⅰ osteotomy＋sagittal split ramus osteotomy （SSRO） was performed in 34 patients, Le FortⅠ osteotomy in 2 patients, SSRO in 111 patients, and mandibular body partial osteotomy in 1 patient. Intraoral vertical ramus osteotomy was unilaterally used in 4 of 145 patients who received SSRO. Genioplasty/genioectomy was performed in 20 patients simultaneously with SSRO. The absorbable osteosynthesis system was principally used for fixation. In Le FortⅠ osteotomy, intraoral plate fixation was exclusively chosen. In SSRO, transcutaneous bicortical screw fixation shifted to intraoral bicortical screw fixation and then to intraoral plate fixation. In genioplasty, intraoral bicortical screw fixation shifted to intraoral plate fixation.

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Patients with facial trauma sometimes have life-threatening injuries and complications, and the management of these injuries should be the first medical priority. Major functional problems and unfavorable esthetics may be discovered later because of non-union of osteotomized segments and extensive scar tissue. Therefore, the treatment of these patients is challenging.
We describe the unreported management of an adult patient with a previous traumatic mandibular fracture by using an orthodontic jumping plate and ClassⅡ elastics during distraction osteogenesis. The patient, a 49-year-old male, visited our hospital in 2015 with a chief complaint of malocclusion and esthetic concerns. At the age of 48, he had fallen from the third floor of his house and was taken to a nearby hospital by ambulance because of multiple fractures. After recovering, he underwent open reduction and internal fixation of the mandible; however, he had been left thereafter with malocclusion and a convex profile caused by a condylar fracture. He showed a symmetric face with a convex profile, extensive soft tissue contraction and a limited mouth opening. In addition, he was unable to protrude his mandible at all. The intraoral view showed several missing teeth, an extruded upper left first molar, with overjet and overbite of 9 mm and 7 mm, respectively. He was diagnosed with a retrognathic mandible caused by a previous mandibular fracture.
Orthognathic surgery is a predictable method for improving posttraumatic malocclusion caused by condylar fracture. We were successful in achieving mandibular advancement in the two-stage mandibular distraction for this patient with limited mouth opening and mandibular anterior movement. Treatment was performed with an orthodontic jumping plate and Class Ⅱ elastics for 24 hours during the distraction period to aid mandibular advancement. Nine mm of mandibular advancement was achieved on both the right and left sides, leading to appropriate occlusion. The patient was satisfied with the postoperative occlusion, and the change in profile from convex to straight.

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In facial asymmetry cases, it is necessary to increase the amount of mandibular setback of the non-deflection side during surgery in order to improve mandibular deviation. We present a case of jaw deformity with facial asymmetry treated by extraction of both maxillary first premolars and the mandibular right first premolar, together with orthognathic surgery.
A male patient, 20 years and 11 months old, who was concerned about the crowding of his front teeth and mandibular deviation, visited our clinic. Intraorally, he had Angle ClassⅢmalocclusion on both the left and right sides, because the mandible showed deviation to the right, but there was no major laterality in the molar tooth relations due to mandibular right molar mesial displacement. Furthermore, there was crowding among the front mandibular teeth.
Cephalometric analysis indicated a ClassⅢskeletal pattern with SNA of 78.8°, SNB of 83.6°, and ANB of －4.8°, as well as mandibular deviation towards the right side. Labial inclination of the maxillary anterior teeth （U1 to SN） was 124.2°, and lingual inclination of the mandibular anterior teeth （L1 to mandibular） was 81.5°.
The patient was diagnosed as skeletal ClassⅢwith edge-to-edge occlusion with midline shift caused by mandibular deviation towards the right side.
We decided to extract both maxillary first premolars and the mandibular right first premolar, and to employ a multi-bracket system. Thereafter, the patient underwent mandibular setback by sagittal split ramus osteotomy. The amount of mandibular setback was approximately 13mm on the left, and approximately 5mm on the right, such that the right molar relationship was ClassⅠand the left was full-step ClassⅡ. In cephalometric results, the SNB angle decreased from 83.6° to 81.1°, and the ANB angle improved from －4.8° to －2.4°. A proper overbite （＋2.0mm） and overjet （＋2.5mm） were obtained. In short, we were able to establish facial symmetry and effectively correct the midline shift.
Asymmetric extraction in consideration of facial asymmetry improved the shift of the midline and the facial asymmetry, and was extremely effective.

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