A survey of the current status of the treatment of jaw deformity in Japan was carried out. Cards requesting participation in the survey were sent to the members of the Japanese Society for Jaw Deformities and 189 facilities (89 clinics of oral and maxillofacial surgery, three clinics of plastic surgery and 97 clinics of orthodontics) answered the questionnaire on the homepage of the Japanese Society for Jaw Deformities. The number of patients who received orthognathic surgeries for jaw deformities between April 2006 and March 2007 in 92 clinics of oral and maxillofacial surgery or plastic surgery was 2926. Regarding the clinical diagnosis, the number of patients with mandibular protrusion with/without open bite and/or asymmetry was 1977 accounting for 68% of all patients. Regarding surgical techniques, bilateral sagittal split osteotomy (BSSO; 2069 cases) was most frequent, accounting for 71%, followed by Le Fort I osteotomy in 787 cases (27%). Intraoral vertical ramus osteotomy, alveolar osteotomy, genioplasty, distraction osteogenesis and other surgical types were applied in 370 cases (13%), 191 cases (7%), 318 cases (11%), 77 cases (2.6%) and 77 cases (2.6%), respectively. Rigid or semi-rigid osteosynthesis systems were used in almost all facilities. The average duration of preoperative orthodontic treatment in non-extraction cases and extraction cases was 13 and 18 months, respectively, and the average duration of postoperative orthodontic treatment was 11 months. The average operation time was 163 minutes and the amount of bleeding was 203ml in BSSO, and those in two-jaw surgery were 285 minutes and 512 ml, respectively. There was a significant correlation between operation time and blood loss in BSSO and two-jaw surgery. The average durations of hospital stay in mandibular osteotomy cases and in two-jaw surgery cases was 15 and 17 days, respectively. Intermaxillary fixations in cases using a metal osteosynthesis system and those using a bioresorbable osteosynthesis system were done in 67 and 29 clinics, respectively, and the respective average duration of intermaxillary fixations was 10 and 11 days. This study revealed the current status of treatment of jaw deformity in Japan.

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Objective: Ultrasonographic (US) observation was carried out in order to investigate bone formation and remodeling after distraction osteogenesis (DOG) using the rigid external distraction (RED) system.
Patients and method: The patients were seven cases of unilateral cleft lip and palate treated using the RED system: six males and one female with the mean age of 19 years. The amount of maxillary advancement by DOG ranged from 7.5 to 17.5mm and the timing of US observation was from 2.2 to 6.9 years post-DOG. B mode US examination of the distracted maxillary anterior wall was performed with a 14-MHz transducer. Bone formation and remodeling were assessed on both cleft and non-cleft sides by evaluating bone continuity and smoothness of the distracted bony gap, respectively.
Results: Continuity of the cortical bone was recognized in six cases, but was, not detectable in one case. On the other hand, the distraction gap was not recognizable in one case on both sides; was obvious in four cases on both sides; and was obvious on the cleft side and detectable on the non-cleft side in two cases.
Conclusion: The diverse aspects of bone formation and remodeling suggest that continuous monitoring is needed after maxillary DOG using the RED system.

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The purpose of this study was to clarify the relationship between the cleavage of bone fragments and the stability of osseous healing after performing sagittal split ramus osteotomy (SSRO).
The subjects were 11 patients with mandibular prognathism who underwent SSRO on both sides (22 rami). These rami were studied immediately after surgery, 6 months thereafter, and 1 year after surgery by computed tomography. The plane passing through the mandibular foramen was designated as the upper plane, while the plane passing through the root furcation of the first and second molars of the mandible was designated as the lower plane. Examining the cleavage at the anterior and posterior borders of distal and proximal bone fragments, the cleaved planes were classified into three types (smooth, stairway, concave) by a modification of the methods of Nemoto T, et al.(J Jpn Stomatol Soc 50: 227-241, 2001).
Many of the concave type anterior borders changed to the stairway type between 6 months to 1 year after surgery, but few changed to the smooth type. Almost all of the stairway and concave type of posterior borders changed to the smooth type between 6 months to 1 year after surgery. Regarding the posterior borders at 1 year after surgery, the cleavage of distal and proximal bone fragments demonstrated stable osseous healing (smooth type) in cases in which the length and width between the bone fragments were large. In order to achieve a stable state of osseous healing at the anterior border, it is therefore important to consider the length between the bone fragments and delete the projection of the distal bone fragment. On the other hand, in order to achieve a stable state of osseous healing of the posterior border, it is important to carefully consider the width between the bone fragments. Sufficient bone contact is necessary for the cleavage of distal and proximal bone fragments in both the anterior and posterior border.
The increased distance of the mandibular ramus due to the posterior movement of the SSRO and the clear absorption of the projection of both distal and proximal bone fragments was not observed from 6 months to 1 year after surgery. Therefore, the remodeling in the cleavage between the bone fragments is considered to play a major role in the osseous healing which occurs after SSRO.

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The purpose of this study was to investigate the relationship between the temporomandibular joint (TMJ) internal derangement and facial asymmetry.
Thirty-two patients (9 males and 23 females) with unilateral TMJ internal derangements were selected as subjects. The mean age was 25.6 years (aged 15 to 40 years). MRI was performed for each subject to identify the intraarticular pathologic status. The method involved angle and linear measurements made from a standardized frontal facial photograph. The soft tissue asymmetry evaluated by the photographs was compared with the skeletal asymmetry assessed by the posteroanterior cephalograms. The relation between soft tissue asymmetry and skeletal asymmetry was examined by Pearson's correlation coefficient test. Association between intraarticular pathologic status and asymmetry was examined by means of Spearman's correlation coefficient by rank test.
In patients with unilateral TMJ internal derangement, a significantly positive correlation was found between soft tissue asymmetry and skeletal asymmetry. The relation between soft tissue asymmetry and skeletal asymmetry significantly correlated with the pathologic stage of TMJ internal derangement.
These findings revealed that there is a significant relation between facial appearance and the progression of TMJ internal derangement.

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We report the case of a patient with congenital myopathy who was surgically treated with rapid palatal expansion using a Rotterdam Palatal Distractor (RPD) for the narrow maxillary arch. The patient was a 20-year-old female showing skeletal Class II, accompanied by hypogrowth of the upper and lower jaws. The patient had a high arched palate, open bite, and narrow maxillary arch. We performed rapid lateral expansion using an RPD, which is a small rapid expansion device without bone screws that allows bone fixation. An improvement of overjet in the molar region, increase in the intermolar width, and improvement of the tongue space were achieved. The results suggest that surgery involving rapid lateral expansion using an RPD is an appropriate treatment for patients with open bite in the anterior region accompanying a narrow dental arch and palate.

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