Facial asymmetry is considered to be caused by the intervention of masticatory muscles, especially the masseter muscle, in some way or another. In skeletal muscles, several proteins, identified immunobiochemically, have been found in specifically high concentrations. A difference in concentration of these muscle proteins in fast-twitch and slow-twitch muscles was found; M-subunit of creatine kinase (CKM) and β-enolase were abundant in fast-twitch muscle, whereas αB-crystallin, S-100_a0 and B-subunit of creatine kinase (CKB) were abundant in slow-twitch muscle. In the present study, the masseter muscles of 5 patients with mandibular asymmetry were immunobiochemically analyzed using muscle fiber type-specific proteins.
Method: Bilateral masseter muscles of the patients were sampled during orthodontic surgery. All samples were kept frozen at -80°C until analysis.
Concentrations of CKM, β-enolase, αB-crystallin, S-100_a0 and CKB were determined by the recentlydeveloped sandwitch-type enzyme immunoassay systems. The results showed that the concentration of αB-crystallin and S-100_a0 on the deviated side was much higher than on the opposite side. The concentrations of CKM, CKB, and β-enolase were not significantly different.

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In this study, mandibular lateral deviation and soft tissue outline were compared in order to observe the effects of changes in the mesurement positions for mandibular asymmetry to soft tissue outline.
The results were as follows:
1) A comparison of each measurement point of the soft tissue showed a strong correlation between the horizontal deviation of the mentalis and the horizontal deviation of the gonion. No significant correlation was seen, however, with thevertical deviation of the gonion.
2) When soft and hard tissues were compared a correlation was found between the midfacial contour and the horizontal deviation of the mentalis as well as a strong correlation with the horizontal deviation of the gonion. With lower facial contours, however, no such correlations were observed.
The results suggested that mid-facial contours are strongly affected by mandible, especially gonion, deviation. It also suggested that the asymmetry of the measuring positions used in this study was not the only factor which determines the lower facial outline.

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In the treatment of skeletal jaw deformity, it is important to improve not only masticatory function but also esthetics with synthetic balance of the soft tissue morphology. In this study, profile changes in the cervicomental made by surgery in skeletal mandibular protrusion were examined, and the results were as follows:
1. Decreased throat length, increased lip-chin-throat angle, and increased cervicomental angle were observed.
2. A significant positive correlation was observed between the lip-chin-throat angle anteroposterior changes of the mandibular position.
3. A significant negative correlation was observed between the throat length and the vertical change of the mandibular position.
4. No correlation was observed between positional changes of the hyoid bone and the cervicomental soft tissue.
Due to the results above, it was suggested that the cervicomental soft tissue was altered after backward transposition of the mandible. In addition, the prognosis seems to become easier by applying the obtained regression curve.

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The purpose of this study was to investigate the postsurgical stability of the mandible in Japanese skeletal Class II patients who underwent sagittal split ramus osteotomy (SSRO). Twelve female patients who underwent surgical mandibular advancement with rigid osseous fixation using titanium miniplates were selected for this study. Seven patients underwent mandibular advancement only, and 5 patients underwent mandibular advancement in conjunction with genioplasty. The postsurgical stability of the mandible was evaluated by cephalometric analysis. As the result, the average mandibular position was stable after SSRO. No relationship was observed between the amount of mandibular displacement following surgery and that during postsurgical treatment, as well as between the amount of mandibular displacement and the mandibular plane angle immediately before surgery.

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The purpose of this study was to investigate the postoperative stability following intraoral vertical ramus osteotomy (IVRO) in skeletal Class III patients. The subjects of the experimental group were the 15 patients who undewent IVRO for mandibular setback without interosseous fixation. As for the control group, 14 subjects who underwent sagittal split ramus osteotomy (SSRO) for mandibular setback with semirigid fixation by titanium miniplate were selected. Cephalometric radiographs were taken 1) immediately before surgery, 2) immediately after surgery, 3) immediately after debonding, and 4) 6 months after debonding. The results of this study showed the IVRO-group had minimal relapse and no significant difference in comparison with the SSRO-group. ln conclusion, judging from the cephalometric analyses, IVRO is an effective method to correct skeletal Class III malocclusion as well as SSRO with semirigid fixation.

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Achondroplasia is a disorder of growth-plate chondrocytes, with short, thick limbs and craniofacial malformation due to lack of development of the nasomaxillary complex. Two cases of achondroplasia with apertognathia, maxillary protrusion, and different malocculusions were reported, and the morphological characteristics of the craniofacial skeleton in each case were discussed. One patient was a 12-year 10-month-old male with anterior open-bite and crowding. The other patient was a 10-year 0-month-old female who complained of remarkable lahial tipping of her maxillary incisors. She had habits of lip biting and tongue thrusting. Both patients had the following common characteristics of craniofacial skeleton and teeth: 1. The anterior cranial base was very large, and the occipital base was small.
2. Both showed skeletal Class III abnormalities due to maxillary retrusion.
3. No unusual abnormality was recognized in the form, number or eruption time of permanent teeth.
4. The maxillary incisors showed marked labial tipping.
However, their malocculusions were different due to the differences in stage of skeletal maturity, degree of maxillary retrusion, oral habits, and function of the muscles surrounding the oral cavity.

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Unfavorable fractures and blood vessel injuries encountered during 196 operations on 185 patients who underwent surgical correction of jaw deformities were studied to analyze the causes. There were 12 unfavorable fractures (6.1%) and 9 blood vessel injuries (4.6%). All complications occurred in two-jaw surgery and sagittal splitting ramus osteotomy (SSRO). Blood loss and operation time were significantly higher in cases with complications than in those without complication in SSRO.
SSRO. With the exception of one case, all fractures were encountered during SSRO. Most of them were minor fractures occurring along the osteotomy line, but relatively large segments of the proximal segment were fractured in 3 cases, 2 of which were not repositioned. Blood vessel injury of the descending palatine artery was encountered in 2 cases of Le Fort I osteotomy. In SSRO, injuries of the inferior alveolar artery, facial artery, and unidentified artery occurred in 3, 1, and 3 cases, respectively. Ligation of the arteries was required to stop bleeding in 2 cases, whereas in the other cases, bleeding was controlled by packing of gauze or oxidized regenerated cellulose.
Insufficient bony cut, forcible splitting, and careless handling of surgical instruments were the main causes of the complications. It is thought that the complications can be avoided by precise analysis of structures at the operation site by computed tomography, sufficient bony cut, and careful handling of surgical instruments.

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Distraction osteogenesis is a technique of bone lengthening with corticotomy and mechanical distraction device to short and/or deformed bones to regenerate bone and soft tissues. This is a clinical report on a severe skeletal class III patient with unilateral cleft lip and palate treated with maxillary bone lengthening by gradual distraction and sagittal split ramus osteotomy of mandible.
The male patient with unilateral (right) cleft lip and palate was 18 years 5 months old at the beginning of surgical orthodontic treatment. After presurgical orthodontic treatment of the maxilla, forward advancement of the maxilla was done by corticotomy and intraoral appliance with two expansion screws fixed to the maxilla. Maxillary lengthening was performed at 0.7mm and 0.35mm advancement per day for 15 days. It was found that SNA increased 3.5 deg., ANS-PNS increased 2.8mm and the maxilla moved anteriorly. Simulteniously SN-NF decreased 3.5 deg. and the maxilla rotated superiorly. Long-term follow-up (25 months after maxillary bone lengthening) demonstrated that the maxilla slightly relapsed posterio-inferiorly.
It was considered that maxillary bone lengthening by gradual distraction is an effective technique to advance the maxilla of cleft lip and palate patient without exacerbating the rhinopharyngeal closure function.

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Since 1989, modified sagittal splitting ramus osteotomy, as modified by Epker in 1977: for surgical correction of mandibular skeletal deformities, has been used at our hospital. Advantages of this procedure are safety, capability of rotating the distal segment horizontally, and maintaining a blood supply to the proximal segment. Compared with Obwegeser-Dal Pont's method, there were no obvious differences in operating time and hemorrhage dose, but the frequency of mental nerve paresthesia was decreased by Epker's method. Minimized soft tissue dissection and short lingual cut of the medial ramus can reduce many complications and simplify the operative procedure. It was suggested that modified sagittal splitting osteotomy by Epker's method was very useful for surgical-orthodontic correction of mandibular prognathism.

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The purpose of this study was to investigate the long-term changes of craniofacial morphology in mandibular prognathism patients treated with two-jaw surgery and to evaluate the stability after surgery. Lateral cephalograms of seven patients (two males and five females) studied for more than two years after surgery, were analyzed for evaluation of craniofacial changes. The materials were obtained at eight stages between the initial and the latest examinations. Dentofacial changes were analyzed and compared between the stages.
The results were as follows:
1. The maxilla was moved forward and downward by surgery (average; anteriorly 4.2mm, inferiorly 3.3mm). Anteroposteriorly, excellent postoperative stability was achieved, although the maxilla slightly displaced posteriorly during intermaxillary fixation. The maxilla was displaced superiorly 1.5mm on average between immediately and 3 months after surgery. However, the vertical change of the maxilla was minimum after 6 months.
2. The mandible was moved backward 12.9mm on average after surgery. Postoperative stability was achieved, while the mandible was displaced forward 1.4mm on average between removal of intermaxillary fixation and 6 months after surgery. A significant negative correlation was found between the amounts of mandibular setback and forward displacement.
3. The maxillary and mandibular incisors moved lingually during intermaxillary fixation and then tended to be slightly inclined labially. After one year, no obvious changes in inclination of upper and lower incisors were observed in most cases.
4. Appropriate overjet has been maintained, while overbite decreased slightly in some cases after surgery. At the latest examination, an acceptable occlusal relationship in the anterior region was maintained in all cases.
From these findings, it was suggested that long-term craniofacial stability and acceptable occlusal relationship in the anterior region were obtained in most cases by two-jaw surgery. On the other hand, vertical relapse of the maxilla occurred immediately after inferior maxillary repositioning. Therefore, it was suggested that an integrated treatment planning be established to prevent vertical relapse of the maxilla.

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Introduction: Facial asymmetry has been one of the important themes in jaw deformities.
The course of treatment for jaw deformities is usually decided in response to cephalometrical analysis, but it is difficult to suspect the movement of soft tissue after surgery. In this paper, asymmetry, caused by the buccal lipoma discovered postoperatively, is discussed.
Case: A seventeen-year-old female visited Hamamatsu University Hospital in 1991 with maxillary retrusion, mandibular protrusion, and facial asymmetry diagnosed cephalometrically. After preoperative orthodontic treatment, Le Fort I osteotomy and ramus sagital split osteotomy were carried out in September 1993. After surgery the cephalometrical asymmetry was improved, but her cheek remained swollen. The excess tissues of the cheek, especially the right buccal fat pad, was thought to be the cause because there were no other abnormal findings such as induration. Then the buccal fat pad was partially removed when the miniplates were removed. However, the facial asymmetry of soft tissue was not improved. After taking a CT and an MRI, the right buccal lipoma with capsule was found. In March 1996, the lipoma was resected, and as a result, her facial asymmetry was corrected.
Discussion: Facial asymmetry is caused by hard tissue and/or soft tissue. In consideration of the incidence of asymmetry among the jaw deformities and the incidence of lipoma in the maxillofacial area, such as this case, soft tissue tumors such as lipoma are thought to be possible causes of facial asymmetry. When evaluating facial asymmetry, especially in cases of facial asymmetry of soft tissue remaining postoperatively, an image diagnosis such as a CT or an MRI should be utilized.
Conclusion: Since soft tissue tumors such as lipoma are possible causes of facial asymmetry, facial asymmetry should be examined carefully.

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The diagnosis of maxillofacial deformities may consist of two aspects: one is primary diagnosis which may be defined as the clinical diagnosis of facial morphology and occlusion based on clinical inspection, the other is secondary diagnosis based on cephalometric analysis, model analysis and so on. Since the chief objective of orthognathic surgery is improvement of facial disharmong and malocclusion, the clinical diagnosis has much to do with the treatment planning and its result. However, clinical diagnosis of the facial morphology greatly depends on the clinician's subjectivity, and it is considered that a great variety of the terminology would be used in the clinical diagnosis.
The purpose of this study was to survey the terminology for clinical diagnosis used by OMF surgeons and orthodontists. The facial pictures (frontal and lateral views) and intraoral pictures in centric occlusion (frontal and lateral views) of four patients with maxillofacial deformity were sent to orthodontists and oral andmaxillofacial (OMF) surgeons who belonged to a dental school or a medical school in Japan. They were simply asked to make a clinical diagnosis for each patient. Seventy-nine OMF surgeons and 16 orthodontists replied. The returned diagnoses were subjected to statistical analysis and the results were as follows:
1) The diagnostic terminology was categorized into six groups:(1) the generic term, (2) prognathism of maxilla or mandible, (3) symmetry, (4) facial height, (5) occlusion, and (6) others.
2) There was a great variety of Japanese terminology applied to the same symptom. It is desired that the diagnostic terminology be standardized and unified.
3) From the diagnoses of facial morphology, convexity of the lower third of the face in the profile view was commonly recognized, but middle-third anteroposterior deficiency, facial asymmetry in the frontal view or difference in facial height were generally not recognized except for a remarkable case.

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