The purpose of this study was to investigate the effect of tapping, gum chewing and muscle fatigue on the power spectrum and integration of the masticators muscles EMG in 10 patients with mandibular prognathism (5 males and 5 females) and in 10 normal subjects (5 males and 5 females). Muscle fatigue in the anterior temporal and masseter muscles was induced by continuous maximum clenching in intercuspal position for 60 seconds.
1. Tapping and Gum Chewing:
The integration of EMG in mandibular prognathism was lower than that in normal subjects. The MPF (Median Power Frequency) of the masseter muscle was almost the same, but the MPF of the temporal muscle was significantly lower in mandibular prognathism.
2. Continuous maximum clenching:
Muscle activity gradually decreased as time passed during muscle fatigue. The integration of EMG in mandibular prognathism was significantly lower. This suggested that these patients had mandibular dysfunction, and it correlated with the histochemical characteristics of the masseter muscle because the distribution of type 2 fibers was significantly lower in mandibular prognathism.
The MPF gradually shifted to the lower frequencies during muscle fatigue in normal subjects, but in some patients with mandibular prognathism, several abnormal findings, such as shifting to higher frequencies and shifting suddenly to lower frequencies, were recognized. The MPF average was almost the same as that of the masseter muscle but the MPF of the temporal muscle in mandibular prognathism was significantly lower.
The EMG power spectral analysis during muscle fatigue was very useful to evaluate the stomatognathic function in Mandibular Prognathism.

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At the Department of Oral Surgery, School of Medicine, Kanazawa University, Fuji Computed Radiography (FCR) system has, been applied for Cephalogram of Jaw deformity patients since April 1991. Generally, FCR images indicate more clear-cut views than screen/film images. The FCR images are wonderfully clear, however, it is very difficult to determine some cephalometric landmarks.
As a result, we evaluated FCR images after operating Workstation system (WS images), the soft tissue profile was obtained as a reversed picture and hard tissue was obtained clearer than the original FCR image. Analyzing cephalometric pictures had no significant differences between FCR image and WS image. But WS image had far superior clearness when compared to FCR image.

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The purpose of this study was to investigate reopening the blood circulation of the maxillae after Le Fort I osteotomy with cutting of the right descending palatine artery utilizing microcorrosion cast by scanning electron microscopy.
Twelve Japanese monkeys were used in this study. Serial examinations of the vascular casts were made on 3 monkeys sacrificed 3, 5, 7, and 10 days after osteotomy, respectively. The acrylic plastic was injected through cannulae inserted into the common carotid arteries by means of the plastic injection method (Ohta et al. 1990). The greater palatine artery decreased in diameter 3 days after osteotomy, however, there was no obvious difference in diameters between the cutting and non-cutting sides. The lesser palatine artery communicating with the ascending palatine artery was obviously increased in diameter. The diameter of this artery became the largest at postoperative 5 days, and gradually decreased to normal size. New vascular formation was observed at the cutting end of the incisal mucoperiosteum, and appeared as penetrated sinusoidal capillaries. At ten days, new sinusoidal capillaries differentiated to obtain independent lumen, then matured to newly-formed capillaries.
In this study, it was said that the ascending palatine artery was an important for supplying to the maxillae after Le Fort I osteotomy with cutting of the descending palatine artery. When microvascular anastomoses were built up at both mucoperiosteal and osteotomy sites, the ascending palatine artery may not play the role of a lateral pathway to the maxillae.

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In this study, to investigate exact changes of the soft tissue profile on the mid-sagittal plane associated with the vertical and horizontal movement of the mandible, 15 females with normal occlusion were measured by using a non-contact 3-D shape measurement apparatus with an image encoder. In the measurement, the mandible of each subject was induced with a bite plate, horizontally downward from the centric position every 1mm (0-4mm), and forward every 1 mm (0-7mm) from each downward position.After each 3-D data of facial soft tissue was overlapped by using FITTING PROGRAM (3D-SPHINX), simple regression linear analysis was performed to obtain the regression formula which determines the 2-D movement of 21 points on the soft tissue profile of mid-sagittal plane to the movement of mandible.As the results of this study, exact ratios of soft tissue changes in relationship to the simple movement of the mandible were clarified.

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Facial asymmetry is often associated with problems in the horizontal dimension, such as a lateral shift of the mandible, or an asymmetrical shape of the mandibular and/or maxillary bones. A vertical dimensional disproportion, such as a difference in height of the mandibular ramus or alveolar bone, is usually included.
In past years, sagittal split ramus osteotomy has often been preferred for treating facial asymmetry even in cases that are caused by vertical problems. However, it has been difficult to achieve satisfactory improvement of facial asymmetry and stomatognathic dysfunction without correcting vertical problems in many cases.
In this report, we present a facial asymmetry case which is characterized by disproportion in the vertical height of the mandibular ramus with an occlusal cant. This patient underwent unilatera lvertical ramus osteotomy on the shifted side and sagittal split ramus osteotomy on the contralateral side. An acrylic splint was inserted to open the occlusion on the shifted side. The patient was then placed into intermaxillary fixation. After bony healing, the splint was removed and the teeth were allowed to elongate into occlusion. Satisfactory stomatognathic function and facial symmetry were obtained after treatment in this case.

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The sagittal splitting ramus osteotomy known as the modified Obwegeser method and Obwegeser-Dal Pont method have been applied in the surgical correction of jaw deformities at our hospital. However, in the severe mandibular asymmetric case, the inside bone fragment pushes the lateral bone fragment on the side of deviation. Sometimes, as the mandibular condyle was rotated due to this interference, TMJ dysfunction was found.Various complicated operational methods have been reported in these cases. But, simple plastic operation is preferred. Also, it is preferred that the influence to the mandibular condyle rate be small.
This paper describes the application of sagittal splitting ramus osteotomy extremely narrowing width of the sagittal split on the side of deviation. The advantage of this method is that the roll of the mandibular condyle head on the side of deviation decreases. Also bone contact is obtained even when the mandibular ramus is elonga-ted. Also, as rigid fixation with a titanium mini bone plate is carried out, the deviation to the top anterior of the small fragment is prevented.

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Nasal airway obstruction due to postoperative swelling of the nasal mucosa may frequently occur after Le Fort I osteotomy. Additionally, as in persistent hemorrhage from the nose, it should become more difficult or impossible to maintain a patient's nasal air passage.
Recently, we used Merocel ^® NASAL PACKINGS on 23 patients who underwent Le Fort I osteotomy. This device is an intranasal pack made of biocompatible synthetic surgical sponge called Merocel, designed to compress the nasal mucosa adequately, and able to maintain the nasal airway with the tube in the center of the pack. The nasal pack was applied to bilateral nasal cavities for three days immediately after extubation.We have found this nasal pack to be useful not only for controlling hemorrhage from the nose, but also maintaining the nasal air passage in postoperative care of the patients who undergo Le Fort I osteotomy.

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We reported a case of skeletal anterior open bite deformity treated with both maxillary anterior and posterior segmental osteotomies. The clinical and radiographic examinations indicated a stable result without relapse. Maxillary posterior segmental osteotomy for skeletal anterior open bite is an effective procedure that could correct the etiological sequence of altered mandibular protrusion, forward tongue posture, and buccal segment extrusion. In addition, combination with maxillary anterior segmental osteotomy shorten the duration of treatment.

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Two cases of severe facial asymmetry resulting from progressive facial hemiatrophy and hemifacial microsomia treated by two jaw surgery and hydroxylapatite (HA) block graft are reported. Both cases had a similar three-dimensional jaw deformity. Two jaw surgeries were performed to improve the occlusal plane inclination and the asymmetric contour of the mandible. HA blocks which were made from wax models on the mandible models reconstructed from CT, were grafted to improve the remaining deformity. Various problems associated with the procedures are discussed.

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Osteogenesis imperfecta is associated with brittleness of bones and multiple fractures and is a hereditary bone ailment often accompanied by blue sclera, auditory disorders, hypermobility of joints, dentinogenesis imperfecta, and other ailments. In Japan there are numerous reports of this in the field of orthopedics and orthodontics, but few from the field of oral surgery.
Recently, we performed mandibular traumatic osteotomy of mandibular prognathism due to mandibular canine to canine fracture and osteogenesis imperfecta. We present our observations with the experience gained.

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A Clinical evaluation was carried out on 68 patients who underwent orthognathic surgery from 1981 for 10 years in the Second Department of Oral and Maxillofacial Surgery, Kagoshima University. The results were as follows:
1. The male-female ratio was 1: 2.
2. The average age was 20, 8 years.
3. Mandibular prognathism was the most predominant diagnosis (66%). Ten (14%) out of 68 patient were accompanied with cleft palate.
4. The extent of mandibular set back in sagittal splitting osteotomy was 10.5mm on the right side and 10.1mm on the left side in average.
5. Excision on the tongue in patients with possible macroglossia. The excised areas were 274.2mm² in average (ranged from 180mm² to 400mm²).
6. In sagittal splitting osteotomy, rigid fixation by use of metal or sapphire screws were employed with the maneuver for repositioning the mandibular condyle. In Le Fort I osteotomy, iliac bone graft and fixation with a miniplate and zygomatic suspension were employed.
7. The operation time for sagittal splitting mandiblectomy was 5hr. 41min. in average (ranged from 3hr. 12min. to 8hr. 26min.), and in bimaxillary osteotomy was 7hr. 12min. in average (ranged from 7hr. 17min. to 9hr.58min.).
8. The mean blood loss was 537.2ml in the sagittal splitting mandiblectomy (ranged from 114m1 to 2140ml), 1041ml in bimaxillary surgery (ranged from 494ml to 2910ml).
9. The routine period of intermaxillary fixation in our department was 14 days for sagittal splitting mandiblectomy, and 21 days for Le Fort I osteotomy.

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We made a clinical evaluation of 52 patients who underwent orthognathic surgery in our clinic during the past 3 years.
The results were as follows:
1. The number of patients showed a tendancy to increase year.
2. They were 11 male and 41 female patients with an average of 24.8 years of age.
3. Most of patients (67.3%) were diagnosed with mandibular prognathism with or without another jaw deformity.
4. 29 patients were operated on by sagittal splitting osteotomy (Obwegeser's method), 14 patients by Wassmund-Wunderer method, 12 patients by anterior alveolar segmental osteotomy for the mandible.
5. The average time of the operation and the average bleeding amounts during operations were 2hr. 28min. and 130ml, respectively, for a sagittal splitting osteotomy, 3hr. 12min. and 440ml, respectively, for bimaxillary anterior alveolar segmental osteotomies.
6. 4 (7.7%) out of 52 patients received blood transfusions.
7. The average period for intermaxillary fixation was as follows: within 3 days for sagittal splitting csteotomy with rigid internal fixation by lag screws and 3 weeks for intraoral vertical ramusos teotomy.
8. 41 patients underwent pre- and post-operative orthodontic treatments.

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Clinical dysfunctional symptoms (clicking and pain) of the temporomandibular joint in 278 patients before and after orthognathic surgery were reviewed retrospectively following orthognathic surgery. All patients underwent bilateral sagittal splitting osteotomy for correction of the mandibular prognathism. The sapphire screws were applied for rigid internal fixation of the fragments in 235 patients and the circumferential wire fixation was performed in 43 patients.
A significant difference in the period of intermaxillary fixation was found for patients were applied screw fixation (an average of 10.9 days) than those who were applied wire fixation (an average of 33.5 days).
It was found that the incidence of temporomandibular joint symptoms in patients who were applied screw fixation had significantly decreased than those who were applied wire fixation after surgery. In addition, the incidence of symptomatic patients with mandibular asymmetry was higher than those with symmetry, preoperatively.

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