The present study was designed to evaluate three-dimensional position of the mandibular condyle relative to the glenoid fossa in adult patients with mandibular prognathism before orthognathic surgery.
Eight adult patients (four females and four males), who were indicated for orthognathic surgery with sagittal splitting ramus osteotomy, were selected as subjects. Seven-layered tomograms of the TMJs were taken from the subjects before treatment.
For evaluating three-dimensional position of the condyle to the glenoid fossa, an analytic method for tomograms of the TMJ was used. In this method, the condyle and glenoid fossa represented a three-dimensional surface model and the shortest distance between the condyle and the glenoid fossa (CGFD) was measured. Before the measurement, the influences of horizontal rotation and vertical inclination of condylar long axis on the CGFDs were investigated in a simulated model of the TMJ.
The CGFDs of the subjects were obtained for five areas on the condyle, i. e. anterior, middle, posterior, lateral and medial regions.Based on these values, the ratio of anterior CGFD to posterior one (A/P ratio) and that of lateral CGFD to medial one (L/M ratio) were calculated in order to evaluate condylar position in the TMJ in the anteroposterior and mediolateral directions, respectively.
The following results were obtained.: 1. The CGFDs obtained by the present technique were very accurate irrespective of horizontal rotation and vertical inclination of the condylar long axis.
2. The CGFDs in the anterior, middle and posterior regions were 2.46±0.43mm, 2.16±0.40mm and 3.36±0.58mm, respectively. Significant difference between the anterior and posterior CGFDs was found at 1% level of confidence. Meanwhile, the CGFDs in the lateral and medial areas were 2.06±0.39mm and 2.26±0.54mm, respectively, and no significant difference can be observed between both values.
3. The A/P and L/M ratios were 0.75±0.16 and 0.94±0.15, respectively.
It is shown that the condyles occupy more anterior position in the TMJ space in this particular subjects before orthognathic surgery.

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Since the occlusogram was introduced by Deguchi et al in 1982, a few articles of occlusogram were reported.
There is, however, no article discussing if occlusogram could be used for diagnosis and treatment plan of surgical orthodontic cases.
There is a little difference in using occlusogram between surgical orthodontic case and non-surgical.
It seemed that the application of occlusogram was useful to surgical orthodontic case.
This article shows how to use an occlusogram combined with lateral cephalometrics correcting incisor relationship to jaw discrepancy for surgical orthodontic cases.
It was not only possible to predict the relation between occlusion and jaw after treatment, but also the distance of right and left setback of mandibular precisely.

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This study is to investigate the change of pulp sensibility on maxillary teeth after performing the combined surgical methods, that we used Le Fort I type osteotomy with anterior maxillary ostotomy.
12 months to 42 months after operation, electric pulp test was carried out on 10 patients who underwent Le Fort I type osteotomy (Le Fort I type group), and 8 patients who underwent Le Fort I type osteotomy with anterior maxilary ostotomy (combination group).
12 months after operation, the positive ratio of pulp sensibility show 92.3% in the combination group, 94.5% in the Le Fort I type group, from now on, the positive ratio in these two groups ascended with time. And for the 42 months after operation, positive ratio shows 98.9%, 99.1%. No significant difference could be found in the positive ratio between these two groups, and in positive ratio of the groups between the anterior region and the molar region.
As a result, it seemed that disturbance of pulp sensibility didn't increase when Le Fort I type osteotomy together with maxillary anterior osteotomy were used.
It seemed that a postoperative observation over 1 year was necessary.

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The purpose of this study is to clarify the morphological changes of mandibular symphysis in surgical orthodontic treatment and to investigate the factors involved.
The subjects consisted of fourteen mandibular prognathism patients who had undergone sagittal splitting ramus osteotomy. The radiographic cephalograms were taken before preoperative orthodontic treatment, before operation, immediately after operation, immediately after removal of intermaxillary fixation and immediately after postoperative orthodontic treatment.
Morphological changes of mandibular symphysis were longitudinally analyzed and the results were as f ollows.
1. The width of mandibular symphysis has decreased during the active treatment, especially during the intermaxillary fixation. During the intermaxillary fixation, elongation and lingual inclination of the mandibular incisors were found with the downward-backward (clockwise) rotation of the mandible and its relation to the decrease in the width of mandibular symphysis were also clarified.
2. The width of labioalveolar bone of the mandibar incisors has decreased during intermaxillary fixation and the correlation between its decrease and the decrease in periodontal bone height during the active treatment was found.
As the morphological changes of the mandibular symphysis were found in the surgical orthodontic treatment aforementioned, the treatment including the diagnosis and the postoperative observation, therefore, should be done in view of the periodontal problems as well.

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This study was designed to examine the histochemical characteristics of the masseter muscle in patients with maxillofacial deformity.Biopsies of the deep surface of the anterior aspects of the superficial masseter were obtained in 21 male patients (18 with mandibular prognathism., 2 with open bite, 1 with maxillo-facial asymmetry) at the time of corrective surgery by sagittal splitting rami osteotomies of the mandible. Controls were 6 normal subjects with normal occlusion.
Individual muscle fibers were classified as type 1 (slow twitch-oxidative), type 2A (fast twitch-oxidative glycolytic) and type 2B (fast twitch-glycolytic) based on ATPase staining.
The normal human masseter muscles had a unique fiber profile compared to that of normal limb and trunk muscles, and type 1 fibers were the largest and type 2 fibers were the smallest in normal subjects. These findings suggest that the masseter muscle is highly adapted to the special and complicated functions of the stomatognathic system.
In patients with maxillofacial deformity, type 1 fibers were the largest and most prevalent type of fiber and type 2 fibers were much smaller than those in normal subjects with statistical significance. Some cases demonstrated evidence of myopathic disorders: type 2 group atrophy, small angulated fibers and type 1 grouping. Targetoid fibers were recognized in one patient. The pattern of type 1 predominance and type 2 atrophy observed in these patients was different from the distribution in a person free of jaw deformities.
It is a very interesting problem on whether the pathologic abnormalities observed in this study represent an underlying neuromuscular problem or a secondary manifestation of muscle stress is caused by a abnormal bone growth.

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Surgical treatment for facial asymmetry patients is one of the most challenging one for surgeons not because the surgical technique for this type of deformity is difficult but because the postoperative care of dental occlusion needed for this type of deformity patients varies considerably from patient to patient. The problems include whether intermaxillary fixation should be used or not, how long it should be maintained if necessary, and what type of occlusal wafers provides a good result according to relapse.
We experienced a case that a patient of facial asymmetry whose deformity was corrected by Le Fort I and bilateral mandibular rami ostotomies presented relapse due to the tension of the suprahyoid muscles immediately after surgery.
Intermaxillary fixation with an interocclusal wafer pivoting at the mandibular molar region of the right side for a week and seven-week period of traction with elastics between arches with this wafer except during meals resulted in a good dental condition.

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Sagittal splitting ramus osteotomy is now a widely used procedure in orthognatic surgery. The techniques are well standardized and carry a low complication rate. Neurological complication resulting from mandibular osteotomy can be found in the inferior alveolar and mental nerves.
In this report, peripheral facial nerve palsy is discovered in a male patient with cleft lip and palate who underwent bilateral sagittal splitting ramus osteotomy for the correction of an anterior open bite associated with mandibular prognathism.
A possible mechanism pertinent to this distressing complication is discussed.

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