Cephalometric prediction is still widely used for treatment planning in surgical orthodontic patients. However, there have been few reports on the relationship between mandibular midline changes by orthognathic surgery and the amount of bilateral setback movement on lateral cephalograms. The aim of this study was to clarify the relationships between the difference in mandibular setback amount for deviated and non-deviated sides and the amount of middle region displacement on cephalometric prediction in patients with mandibular prognathism and deviation.
The subjects comprised 15 patients diagnosed as mandibular prognathism with skeletal deviation at the orthodontic clinic, Niigata University Medical and Dental Hospital. All patients underwent only mandibular setback surgery involving midline correction by sagittal split ramus osteotomy（SSRO）. Frontal and lateral cephalograms taken just before and immediately after orthognathic surgery were used for measurements. X-Y coordinates were constructed using the occlusal plane on the preoperative lateral cephalogram for the X coordinate and the perpendicular line drawn intersecting the X line at the Sella for the Y coordinate. The amount of posterior movement of the distal segment and middle region displacement were determined by superimposition of pre-and postoperative lateral cephalograms. The postoperative midline changes were measured linearly using a study model taken at just before orthognathic surgery. We examined the relationship between the average amount of operative movement for deviated and non-deviated sides and the amount of anteroposterior changes of the incisal region. The relationship between the difference in operative movement for deviated and non-deviated sides and postoperative midline changes was also examined.
Significant correlations were found between the bilateral difference of operative movement and the amount of anteroposterior changes of the incisal region. A significant correlation was also revealed between the bilateral difference of operative movement and horizontal middle region. In addition, a significant regression formula was obtained as β=0.65α+1.17（α: bilateral difference of mandibular posterior movement （mm）, β: lateral movement of mandibular midline（mm））by regression analysis.
The present results suggest that, in cases with skeletal deviation, it is possible to regard the average value of anteroposterior movement of distal segments on both sides as a predictive factor for the posterior position of the incisal region. Also, the results suggest that the amount of midline correction can be predicted from the bilateral difference of operative movement. Since there is diversity and much variation in the movement of distal segments, it is not easy to predict the amount of midline displacement during orthognathic surgery. However, this regression formula may be useful for orthodontists and surgeons to plan surgical orthodontic treatment.

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Treatment for cases with midface hypoplasia such as Apert syndrome and Crouzon syndrome should aim to achieve well-harmonized occlusion and maxillofacial morphology. To date, orthodontic treatments using Le Fort Ⅲ osteotomy concomitant with Le Fort Ⅰ or Ⅱ osteotomy have been reported. In this paper, we present a case with Apert syndrome treated by Le Fort Ⅲ distraction osteogenesis （LFⅢDO） followed by open rhinoplasty with iliac bone grafting and Le Fort Ⅰ osteotomy.
The patient was a 16-year-old girl with Apert syndrome. She was characterized by severe midface hypoplasia representing skeletal Class Ⅲ occlusion with open bite. After the completion of preoperative orthodontic treatment, 12mm of midface advancement was performed by LF Ⅲ DO by using an internal distraction device. After the DO, although anterior open bite was slightly worse, midface hypoplasia and proptosis were significantly improved. Open rhinoplasty with iliac bone grafting was carried out 2 months after the LF Ⅲ DO. 5 months after the rhinoplasty, Le Fort Ⅰ osteotomy was performed to correct the anterior open bite.
As a result, well-harmonized occlusion and maxillofacial morphology were achieved by close cooperation between the orthodontist, oral and maxillofacial surgeons and plastic surgeons.

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We report two cases of genioplasty performed using a navigation system. In recent years, virtual orthognathic surgeries have been performed using simulation software with data from preoperative computed tomography （CT）, and the osteotomy design, direction and distance of bony segment movement have been established. Despite the accuracy of simulations using three-dimensional CT data, results obtained from simulations cannot be effectively applied to clinical practice unless comparisons can be made to actual surgery. We report our experience of performing genioplasty using simulation software with preoperative CT data, and established the osteotomy design as well as the direction and distance of bony segment movement. Simulation-guided navigation osteotomy was performed with reference to simulation results transferred to the navigation system. A reference antenna was attached to the head of the patient using a headband. Next, interfacing laser registration was performed. Osteotomy was then performed along the osteotomy line drawn on the chin bone surface using piezosurgery and a tracker, and the bone segment was mobilized by down-fracture using a bone saw. Using the image of the simulated repositioned bone segment shown on the navigation system screen, the bone segment was moved to the determined position and fixed. Our results suggest that use of a navigation system allows safer, more precise genioplasty.

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Juvenile idiopathic arthritis （JIA）, one of the most common chronic diseases in childhood, causes significant limitation in sagittal and vertical mandibular growth, resulting in severe retrognathia and anterior open bite with strong esthetic and functional restriction. We present a case of two-jaw surgery in a retrognathia patient with marked resorption of mandibular condyle due to JIA. The patient was a 12-year-old female at the first presentation. She showed a severe retrognathia and anterior open bite. The condyle of the mandible was remarkably resorbed and located anteriorly. The condition of JIA was well controlled by medication. Under the diagnosis of retrognathia and open bite due to JIA, surgical orthodontic treatment started at the age of 13 years old. The first premolars and the third molars were extracted during preoperative orthodontic treatment. Two-jaw surgery by Le Fort I osteotomy and sagittal split ramus osteotomy was performed under general anesthesia at the age of 19 years old. The maxilla was rotated counterclockwise and moved 6mm upward at the incisors. The mandible was advanced 7 mm and rotated accordingly. Genioplasty was performed with the advance of 5mm. The postoperative course was uneventful without infection or delayed wound healing. Active orthodontic treatment ended 10 months after surgery and the fixation plates in the mandible were removed 1 year and 7 months after surgery. No remarkable relapse or further resorption of the condyles was observed. Her profile and occlusion have greatly improved and been maintained in the condition as planned for 2 years and 2 months after surgery.

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Impacting the posterior of the maxillary bone is effective in treating skeletal open bite with retrognathic mandible. However, a slight relapse has been observed in long-term stability following impaction of the upper molar segment. We report the retention of two skeletal open bite cases five years after surgery, each treated with multi-segmented Le Fort Ⅰ osteotomy （impaction of upper molar segments） and bilateral sagittal split ramus osteotomy （advancement and counterclockwise rotation of the mandible）, respectively. Case 1: Skeletal open bite with root resorption of incisors. During surgery, the upper molar segments were impacted 5mm, the upper incisor segment was impacted 3mm, and the mandible （lower incisors） was advanced 4mm and moved upwards 5mm. Five years after surgery, the upper molars extruded 2mm and the mandibular plane angle increased 3.7 degrees. Root resorption progressed during treatment. Case 2: Skeletal open bite with temporomandibular joint deformity. Pre-surgical orthodontic treatment was followed up with surgically assisted rapid palatal expansion and extraction of the upper first premolars. During surgery, the upper molar segments were impacted 5mm, the upper incisor segment was impacted 3.5mm, and the mandible （lower incisors） was advanced 1mm and moved upwards 4.5mm. Five years after surgery, there were no significant changes. A slight relapse was observed in one of two skeletal open bite cases treated with multi-segmented Le Fort Ⅰ osteotomy and bilateral sagittal split ramus osteotomy.

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Intraoral vertical ramus osteotomy （IVRO） does not achieve internal fixation; therefore, it requires measures to prevent complications from the need for postoperative maxillomandibular fixation （MMF） or strong intermaxillary rubber traction in a short period of time after surgery. We have devised a breathing management splint （BMS） to manage breathing and prevent complications after IVRO. From September 2011, BMS was applied to patients who chose IVRO. In this report, we describe the procedure and management of BMS after IVRO in a typical case and also investigate postoperative nausea and vomiting （PONV） occurrence on BMS application. BMS is used to maintain a gap in the anterior teeth by raising the bite for a few days immediately after surgery. This is one of the methods used to manage problems such as airway obstruction by PONV, difficulty in breathing due to postoperative swelling, and failure of sputum discharge due to MMF, while offering the benefits of IVRO. It uses the benefits of the harmonious relationship formed by adaptive changes in the muscles. The temporomandibular joint is rebuilt once IVRO helps the occlusion to function again after surgery. BMS is also expected to improve the functions of the temporomandibular joint without changing the conventional method. Therefore, it is a highly useful and convenient management method used during MMF, with respect to the patient as well as the medical field.

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