It has been suggested that a relationship exists between severe temporomandibular joint (TMJ) pathology and craniofacial morphology. Although mandibular retrognathism has been reported particularly frequently, no reports have addressed acquired facial deformity of patients with mandibular prognathism. This study investigated the relationship between TMJ pathology and mandibular prognathism. In total, 160 female patients with malocclusion and suspicion of having TMJ disk displacement were enrolled in this study. Their mean age was 27.2 years (range, 15.0-56.0 years). Cluster analysis was performed on eight variables from the lateral cephalogram to evaluate differences in craniofacial morphology. The subjects were classified into a mandibular prognathism (MP) group (n = 59), class I group (n = 64), and micromandibular (MM) group (n = 37). The MP group was further subdivided into a high-angle MP (HMP) (n = 18), average-angle MP (AMP) (n = 35), and low-angle MP (LMP) group (n = 6) according to the cluster analysis results. Magnetic resonance imaging and orthopantomography were performed to identify each subject's intra-articular pathologic status. Orthopantomography was used to analyze the measurements of the mandibular condyle and ramus. The status of the TMJ was classified as disk displacement with/without reduction, osteoarthritis (OA), or normal. The relationship between the status of the TMJ and the craniofacial morphology was statistically investigated. The incidence of disk displacement and OA were lowest in the MP group and highest in the MM group with statistical significance. Additionally, the incidence of disk displacement without reduction was highest in the MM group with statistical significance. The greatest condylar height and condylar/ramus ratio occurred in the MP group with statistical significance. The next greatest occurred in the class I and MM groups, respectively. The smallest ramus height occurred in the MM group with statistical significance. There were no significant differences in the incidence of any TMJ pathology status among the three MP groups. The greatest condylar height occurred in the HMP group with statistical significance; the next greatest heights occurred in the LMP and AMP groups, respectively. The greatest ramus height occurred in the LMP group with statistical significance; the next greatest heights occurred in the AMP and HMP groups, respectively. The highest condylar/ramus ratio occurred in the HMP group with statistical significance.
CONCLUSIONS: This study suggests that patients with mandibular prognathism have a lower risk of onset and progression of TMJ disk displacement than do patients without mandibular prognathism. No definite correlation exists between the vertical craniofacial morphology of mandibular prognathism and TMJ pathology.

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The Dental Aesthetic Index (DAI) is an orthodontic index based on socially defined aesthetic standards. The DAI score, which divides the continuous index score in orthodontic care programs and malocclusion prevalence studies into four malocclusion severity levels, is used for measurement. The purpose of this study was to measure the DAI score of jaw deformity patients in the Department of Orthodontics, Dental Hospital, Tsurumi University. The subjects consisted of 314 patients, who were classified into 11 types according to the characteristics of their malocclusion. The DAI score was calculated on gnathostatic models of the subjects according to the WHO guidelines. The mean score of all the subjects was 49.1 ± 15.8. Subjects with a score of more than 90% were classified into Grade 3 or 4, which represented severe malocclusion and very severe or handicapping malocclusion. However, less than 10% of subjects were classified into Grade 1 or 2, even though they showed severe horizontal deformity. The results clearly suggest that the DAI score is useful for evaluating the necessity of orthodontic treatment in patients with anteroposterior and vertical skeletal deformities. Nevertheless, the DAI score has limitations for evaluating horizontal skeletal deformities.

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To obtain information on the actual condition of dental decompensation by incisor inclination with presurgical orthodontic treatment (PSO) and to prove the effectiveness of PSO in patients with mandibular prognathism, upper and lower incisor inclinations after PSO and the change of incisor inclination with PSO were examined.
Fifty-three patients with mandibular prognathism who had been treated with orthognathic surgery in the University of Tokyo Hospital (UTH) were included in this study. Upper and lower premolar extraction was carried out in 32 and 6 patients, respectively. Mandibular setback surgery (sagittal split ramus osteotomy or intraoral vertical ramus osteotomy) was performed in 39 patients and bimaxillary osteotomy (Le Fort I osteotomy and mandibular setback surgery) in 14 patients. Orthodontic treatment had been performed at UTH for 20 patients and at other private clinics for 33 patients. Lateral cephalograms taken before (T0) and after (T1) PSO were used and SNA, SNB, ANB, Wits value, overjet, overbite, upper and lower incisor inclinations (U1-FH, L1-MP) were measured. Amount of jaw movement was estimated using dental models at T1.
PSO was effective in decompensating the incisor inclination but many patients still had labial inclination of the upper incisors and lingual inclination of the lower incisors after PSO. Labial inclination of the upper incisors was improved in cases with upper premolar extraction, but it became worse in cases without extraction. The mandibular dentition was aligned without premolar extraction in most patients. Lingual inclination of the lower incisors had improved but it was not adequate in many patients. Comparing patients who were treated by bimaxillary osteotomy and by mandibular setback surgery, the bimaxillary patients had more severe skeletal disharmony but the difference between these patient groups in the incisor inclinations after PSO was not significant. There were no differences between the surgical procedures and between clinics in which PSO was performed.
PSO was effective for the decompensation of incisor inclination but the dental compensation remained after PSO in many cases. Premolar extraction was useful for improvement of the incisor inclination in maxilla. Further studies on the crowding before treatment, on the use of anchorage for tooth movement and on the acceptable goal of presurgical-orthodontic treatment are required.

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In subjects with facial asymmetry, it is generally accepted that the maxillary frontal occlusal plane inclines toward the deviated side of the mandible. However, a few patients with facial asymmetry have their frontal occlusal planes inclined toward the contralateral side of the mandibular deviation. The aim of this study was to elucidate the morphological features of the subjects with mandibular deviation with the frontal occlusal planes inclined toward the contralateral side.
The sample consisted of 40 patients whose Menton was deviated at least 2.0 mm from the facial midline. They were divided into two groups based on the relationship between the side of inclination of the frontal occlusal plane and the side of the mandibular deviation. Group IL consisted of 20 patients whose frontal occlusal plane inclined to the ipsilateral side of the mandibular deviation, while Group CL consisted of 20 patients whose frontal occlusal plane inclined to the contralateral side of the mandibular deviation. Then, we compared the two groups using 1) lateral cephalometric analysis, 2) P-A cephalometric analysis, 3) frontal soft tissue analysis and 4) dental casts analysis.
The following findings were obtained:
1. In Group CL patients, not only the frontal occlusal plane defined by bilateral molar positions, but also the maxilla itself significantly inclined toward the contralateral side of the mandibular deviation.
2. In Group CL patients, the maxillary dental midline was significantly deviated toward the contralateral side of the mandibular deviation.
3. The difference in bilateral mandibular ramus lengths was significantly smaller in Group CL patients.
4. In Group CL patients, the mandibular molar compensation for the mandibular lateral deviation was significantly less than that in Group IL patients.
5. In Group CL patients, both the midline and cant of the upper lip were significantly deviated toward the contralateral side of the mandibular deviation.
6. The incidence of missing or buccolingual version of maxillary premolar teeth was significantly higher in Group CL patients.

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In order to analyze the characteristics of dental compensation in facial asymmetry cases, three-dimensional morphological analysis was used to examine the relationships between relative position and attitude of the mandible to the cranio-maxillofacial complex and the upper and lower dentitions to their own bones. Virtualized patient models, which had been reconstructed from 16 patients with facial asymmetry, were used in this study. These models were segmented into four components, including the cranio-maxillofacial complex (CMC), the mandible (Md), the upper dentition (UD) and the lower dentition (LD), and the reference coordinates of four components were established, respectively. The geometric features of the virtualized patient models were extracted from the following three data concerning their relative positions and attitudes: Md to CMC, which represented degree of skeletal asymmetry, UD to CMC, and LD to Md, which represented dental compensation. Correlations of degree of skeletal asymmetry with relative positions and attitudes of upper and lower dentitions to the supporting bones were examined. Morphological analysis showed strong negative correlations between attitude of Md to CMC and attitude of LD to Md on the axial plane (r = -0.76), attitude of Md to CMC and attitude of LD to Md (r = -0.64), and transverse position of Md to CMC and LD to Md on the axial plane (r = -0.59). Strong positive correlations were observed between attitude of Md to CMC and UD to CMC (r = 0.92), and transverse positions of Md to CMC and UD to CMC (r = 0.80). These results indicate that the upper and lower dentitions have three-dimensionally complicated compensatory phenomena of their attitudes and positions for intermaxillary jaw discrepancies, i.e., dental compensation, in facial asymmetry cases. Also, it is suggested that three-dimensional elimination of dental compensation is necessary to properly improve facial asymmetry by orthognathic surgery.

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Introduction: Titanium osteosynthesis plates are widely used for fixing bone fragments in orthognathic surgery. However, there have been few reports on the need or appropriate timing for removing these plates. Therefore, we performed a clinical study on cases in which titanium plates were used in orthognathic surgery at our department for 5 years since 2006.
Subjects and Methods: The subjects were 107 patients who underwent orthognathic surgery performed using titanium osteosynthesis plates from January 2006 to December 2010. The number of male and female subjects, number of subjects in each age group, period of use of the plate, duration of surgery and hemorrhage volume upon removing the plate, number of complications that developed after removal, and number of subjects with a complication based on the period of use of the plate were investigated.
Results: Among the 107 subjects, 91 underwent removal of the osteosynthesis plate and 16 did not undergo this surgery. The male/female ratios of the subjects who did and did not undergo removal were 1:1.39 and 1.67:1, respectively. The average age at removal of the plate was 23.8 years old and the number of subjects in their 20's was 61, the largest among all age groups. The subjects who did not undergo plate removal after orthognathic surgery had an average age of 25.8 years old and 12 of these subjects were in their 20's, also the largest among the age groups. The most common period of use of the plate before removal was 12 months (41/91 subjects). There were no significant differences in the duration of surgery and hemorrhage volume based on the period of use of the plate in subjects with single use of SSRO, concomitant use of SSRO and LF-I, single use of osteotomy for supramaxillary anterior alveolar bone, and single use of mentoplasty. Nine subjects developed a complication after removal of the plate and the rate of complications showed a significant dependence on the period of use of the plate.
Conclusion: Our results suggest that a titanium osteosynthesis plate should be removed about 12 months after orthognathic surgery. There is a risk of complications such as paresis if the plate is used for a longer period.

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The advantage of autologous blood transfusion during orthognathic surgery is widely recognized in Japan. In the Department of Oral and Maxillofacial Surgery at Tokyo Medical and Dental University (TMDU) Dental Hospital, we have performed stored autologous blood transfusion (SAT) during orthognathic surgery since November 2006. In this study, we examined the patients who underwent orthognathic surgery with or without autologous blood transfusion. The subjects were 250 patients with jaw deformities who underwent orthognathic surgery in our department from 2008 to 2012. The results were as follows:
1. Between the group undergoing SAT and that without SAT, there were no significant differences in sex, age, height, weight, total blood volume and blood loss during operation.
2. In the group undergoing Le Fort I + Sagittal split ramus osteotomy, there was a high proportion of cases undergoing SAT, while there was a high proportion of cases without SAT in the group undergoing sagittal split ramus osteotomy.
3. The rates of decrease of red blood cell count, hematocrit value and hemoglobin value from pre-admission to post-operation showed no significant difference between the group undergoing SAT and that without SAT.
4. No case underwent SAT with homologous blood transfusion.
5. The largest number of accidents at the time of storing autologous blood was dysphoria.
6. The mean dose of SAT was 526.5 ± 194.8 mL.
In addition, we reviewed the Japanese literature (including this literature) to examine the current situation of autologous blood transfusion during orthognathic surgery in Japan. We found that SAT is used at all hospitals, but the amount of autologous blood transfusion during orthognathic surgery varied from hospital to hospital.
In conclusion, autologous blood transfusion during orthognathic surgery is useful to avoid homologous blood transfusion. However, it is desirable to produce guidelines on the amount of autologous blood transfusion during orthognathic surgery in Japan.

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A statistical survey of orthognathic surgery was performed on the cases for the last 12 years, from 2000 to 2011, in the Department of Maxillofacial Surgery, Tokyo Medical and Dental University.
1. The number of orthodontic surgery cases was 577, with 257 males and 320 females.
2. The mean age at surgery was 25.4 ± 6.2 years old. Patients in their teens and twenties accounted for 77.7% of the subjects.
3. The most common clinical diagnosis was mandibular prognathism without other condition, accounting for 53.8%. Mandibular prognathism with and without other conditions accounted for 88.0%.
4. The most common bone fixation until 2008 was screw-fixation, accounting for about 70% of the cases in a year. Miniplate fixation increased from 2009, to 79.1% of the cases in 2011.
5. The most common surgical method was sagittal split ramus osteotomy (SSRO), accounting for 80% of the cases in 2000. The combination of Le Fort I osteotomy and SSRO has been increasing.
6. The average operation time was 212.3 ± 70.8 minutes and the amount of bleeding was 337.2 ± 371.2ml in SSRO, and 358.5 ± 87.5 minutes and 692.9 ± 442.7ml respectively in the combination of Le Fort I osteotomy and SSRO.
7. The average duration of hospital stay was over 20 days in 2000, but 12 days in 2011.

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