The occlusal plane often passes through the dens in persons with normal maxillofacial morphology. However, In patients with severe jaw deformity, the occlusal plane may widely deviate from this level, upward or downward. In such cases, abnormalities are often observed in the inclination of the occlusal plane. But the posterior point of the occlusal plane has been unknown in surgical correction of the occlusal plane.
We analyzed individual normal occlusion, mandibular protrusion without maxillary hypogrowth, mandibular retrusion, and mandibular protrusion with maxillary hypogrowth, with regard to the position where the posterior extension of the occlusal plane crossed the cervical vertebrae, on cephalometric radiograms of the facial profile.
As a result, in individual normal occlusion, the occlusal plane crossed around the upper 1/4 of the length of the dens from the midpoint of the basement of the dens. In mandibular protrusion without maxillary hypogrowth, the occlusal plane in males crossed around the lower 1/2 of the length of the dens from the midpoint of the basement of the dens, and the occlusal plane in females crossed around the upper 1/10 of the length of the dens from the basement of the dens. In mandibular retrusion, the occlusal plane in females crossed around the upper 2/3 of the length of the dens from the midpoint of the basement of the dens. In mandibular protrusion with maxillary hypogrowth, the occlusal plane in males crossed around the lower 3/4 of the length of the dens from the midpoint of the basement of the dens, and the occlusal plane in females crossed around the lower 1/2 of the length of the dens from the midpoint of the basement of the dens.
In orthognathic surgery, we considered that the posterior reference point of the anterio-posterior inclination of the occlusal plane is determined using the DENS Index in individual normal occlusion, and is useful in planning treatment for severe jaw deformity.

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The purpose of this study is to examine pre- and postoperative self-evaluation of the face in jaw deformity patients, and to determine its differences between patient and doctor, using a specially prepared questionnaire.
The subjects were 20 mandibular prognathism patients (11 males and 9 females) who underwent orthognathic surgery in our department clinic, and their 20 orthodontists. The questions consisted of the following five items:(1) preoperative recognition of facial deformity, (2) self-evaluation of facial components in the preoperative stage, (3) expectation of facial change in the preoperative stage, (4) postoperative recognition of facial change, (5) selfevaluation of facial components in the postoperative stage. The answer for each question was graded. Characteristics of facial evaluation in male and female patients were statistically analyzed. The accordance ratio of facial evaluation between patient and doctor was also examined.
The results were as follows:
1. In both male and female patients, the preoperative recognition of facial deformity showed high ratings for the facial outline, mandible, and occlusion, and besides these areas, in female patients it also showed a high rating for the chin. The accordance ratio between doctors and female patients was generally high for all facial parts, while in male patients it was low for the chin and the upper and lower lips.
2. In the self-evaluation of facial components in the preoperative stage, male patients showed a significantly low rating for occlusion, and female patients for the mandible and occlusion. Both male and female patients showed high accordance ratios with their doctors for all facial parts.
3. In the expectation of facial change in the preoperative stage, the ratios of male patients were significantly high for occlusion, the mandible, and facial outline, and the ratios of female patients were high for occlusion and the mandible. For occlusion and mandible, both male and female patients showed high accordance ratios with their doctors.
4. In the postoperative recognition of facial change, both male and female patients showed significantly high ratings for facial outline, the mandible, and occlusion. The accordance ratio between doctors and female patients was generally high for all facial parts, while in male patients it was low for the chin and the lower lip.
5. In the self-evaluation of facial components in the postoperative stage, both male and female patients showed high ratings for all facial parts. The accordance ratio between doctors and female patients was generally high for all facial parts, while in male patients it was low for the cheek and the upper and lower lips.

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The purpose of this study was to investigate the correlation among preferred chewing, the deviated side of the mandible, and the horizontal condylar angle.
Subjects consisted of 32 adult patients with mandibular asymmetry.
1. No significant differences were found between the angle of the condylar long axis and the deviated side of the mandible.
2. No significant differences were found between the preferred chewing side and the deviated side of the mandible.
3. There was a significant difference between the horizontal condylar angle and the preferred chewing side. The horizontal condylar angle was in accord with the preferred chewing side.
4. It is suggested that the mastication pattern has a close relationship with the balance of the condylar angle.
5. All but one subject with mandibular asymmetry had a habit of one-sided chewing.

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In cleft lip and palate patients, functional and esthetic correction of severe dentofacial deformity may require not only Le Fort I maxillary osteotomy but also rhinoplasty.
We investigated the order of these two kinds of surgeries in 6 cases with cleft lip and palate. In three cases, Le Fort I maxillary advancement was preceded by open rhinoplasty with a cantilever iliac bone graft (Group A). In the other 3 cases, open rhinoplasty was preceded by Le Fort I maxillary advancement (Group B). The changes of nasal tip protrusion, the nasolabial angle, and the nostril form were evaluated in nasal morphology. Measurements were performed using facial photographs and lateral cephalograms.
In group A, nasal tip protrusion was decreased after the two surgeries. On the other hand, it was clearly increased after the two surgeries in group B. The nasolabial angle showed various change patterns in both groups. The final nostril form was better in group B than in group A. These results suggested that open rhinoplasty with a cantilever iliac bone graft before Le Fort I maxil lary advancement may lead to a better surgical outcome in nasal shape.

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We present a case of Crouzon disease treated by orthodontic treatment and Le Fort III midface advancement osteotomy. The patient was an 11-year-and-4-month-old female with a severe class III malocclusion and a skeletal open bite due to retarded maxillary growth, at initial examination. Preoperative orthodontic treatment was started with a multibracket appliance (0.018 slot, standard edgewise) after the maxillary second premolars and the mandibular first premolars were extracted. At the age of 15 years and 8 months, a Le Fort III osteotomy was performed for midface advancement. The skeletal and dento-alveolar changes following the surgical orthodontic treatment were evaluated. As a result, no relapse of the advanced midface was recognized. Also, the mandibular position, which had been rotated counter-clockwise with surgery, was not changed. Anterior open bite, however, occurred during the retention period. After applying a plate with a tongue crib instead of a Hawley-type retainer, her anterior relation improved.

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We report a case of bilateral hypertrophy of the masseter muscle, judging from the axial CT. A 14-year-old girl was referred to our clinic complaining of bilateral protrusion around the angular region of the mandible. There was, however, no morphological abnormality in the mandible. Axial CTs revealed that the widest portion of the masseter muscle was 18mm and this volume of the muscle was statistically wider than that of other females of approximately the same age. Under general anesthesia, the bilateral deeper layers of the masseter muscle were intra-orally resected. Training in mouth opening was started at 5 days after the operation, and she achieved an adequate opening range of motion. On axial CTs at one year after her surgery, the volume of the masseter muscle was reduced to 61% compared with the original volume. She was satisfied with the result of the operation, cosmetically and functionally.

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A case of unilateral condylar hyperplasia is reported.
The results were as follows.
The patient, whose symptoms were manifested in early adolescence, was diagnosed as having cryptogenic and genuine condylar hyperplasia. This case showed facial asymmetry accompanied by a tilt of the occlusal plane.
Functional mandibular movement was obtained by a high condylarectomy and preserving the disk of the temporomandibular joint. In addition, two-jaw surgery was selected secondarily, because of severe facial asymmetry with a tilt of the occlusal plane, and it resulted in favorable facial morphology and occlusion.

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A 20-year-and-6-month-old female patient had undergone mandibular lengthening by distraction osteogenesis for an Angle Class II division 2 case with micrognathia. We experimented with facial, skeletal, and airway changes using cephalometry, and she was also analyzed for the possible changes of oral functions between before and after treatments.
The results were as follows:
1) The mandibular lengthening was effective within ten days, and the patient's profile and jaw relationship were improved, respectively, after the treatment.
2) A relapse was not seen and the post-treatment conditions were stable after removing the lengthening device.
3) As for the airway analysis, the nasopharyngeal airway was expanded following the mandibular lengthening.
4) As for oral functions, mouth opening increased and electromyogram activity increased after the mandibular lengthening. Harmony between the temporal and masseter muscles was obtained.
From these results, it was suggested that mandibular lengthening by distraction was a favorable technique to advance the mandible of a Angle Class II case with micrognathia.

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