Recently, there have been remarkable developments in the treatment of jaw deformities. Nowadays, surgical correction of jaw deformities is performed at maxillo-facial surgery clinics throughout Japan.
This paper discusses the history of surgical treatment for correction of jaw deformities in Japan. It also discusses the rationale behind the author's introduction of the sagittal splitting method of the mandibular rami for treatment of mandibular prognathism, and reports the results of the first and second cases treated using this method in 1969. Then, it discusses various methods used by the author in orthognathic surgery. As a historical background, the development by Prof. Hugo L. Obwegeser of sagittal splitting of the mandibular rami and LeFort I osteotomy, which are among the most important procedures in orthognathic surgery, are introduced. The factors that have influenced the development of the treatment of jaw deformities in Japan are considered, and finally the challenges involved in the treatment of jaw deformities are discussed.

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The purpose of this study was to cross-sectionally evaluate the effects of postoperative training with chewing gum on masticatory efficiency, maximum bite force and masticatory movement in patients who underwent surgical orthodontic treatment.
The subjects consisted of 23 skeletal Class III patients who had been followed-up for more than 5 years since their active treatments and were classified into two groups: one group consisted of 11 patients who were given the training with chewing gum to improve their masticatory function (Training group) and the other 12 patients who received no training at all (Nontraining group). Furthermore, the control was selected for evaluating the masticatory function phase of the subjects and was categorized into two details: one group consisted of 11 persons with normal dentition (Normal group) and the other group consisted of 10 skeletal Class III untreated persons (Non-treatment group). All the samples were adult females and did not have any clinical symptoms of temporomandibular disorders.
The results were as follows. 1) The masticatory efficiency and maximum bite force of the Training group were recognized to be significantly much higher than in the Non-treatment group, and they got closer to the Normal group. However, there was no significant difference between the Non-training group and Non-treatment group. 2) The chewing stability of the Training group, Non-training group and Non-treatment group was less than or comparable to that of the Normal group. The surgical orthodontic treatment and training with chewing gum had no influence on the chewing stability.3) The chewing shape on the frontal plane of the Training group, Non-training group and Non-treatment group was narrower than that of the Normal group and was not influenced by the surgical orthodontic treatment nor training with chewing gum. 4) It was suggested that the postoperative training with chewing gum had effects on masticatory efficiency and maximum bite force, and that maximum bite force was one of the factors for improving masticatory efficiency.
The following conclusions were obtained. The surgical orthodontic treatment and the postoperative training with chewing gum had little effect on chewing movement of skeletal Class III patients. However, it was suggested that the postoperative training with chewing gum has a positive influence on the learning effect of the patients' masticatory system from the research results of having a significant beneficial effect on masticatory efficiency and maximum bite force.

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Objective: This study examined the usefulness of miniplate fixation in SSRO.
Subjects and Methods: The subjects were 40 patients (20 males and 20 females). On cephalograms taken before surgery (TO), immediately (T1), 2 months (T2), and 1 year (T3) after surgery, the facial angle, SNB, L1 to mandibular plane angle, U1 to SN plane angle, mandibular plane angle, Y-axis, and Pogonion were measured; and from frontal cephalograms, left and right Go-Go' were measured. The patients were also examined for temporomandibular joint symptoms and lower lip paresthesia.
Results: Relapse was observed between T1 and T2, but no significant difference was noted between T2 and T3.Analysis of frontal cephalograms revealed a significant difference on the right side between TO and T1, but no significant changes thereafter, and no significant changes on the left side pre- or postoperatively. Temporomandibular joint symptoms were present on 5 sides each pre-and postoperatively. Lower lip paresthesia remained on 19 sides (23.8%).
Conclusion: Compared with screw fixation, miniplate fixation in SSRO resulted much less frequently in postoperative relapse, indicating its usefulness in SSRO.

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A 21-year-old female presented a class III malocclusion with facial asymmetry. The patient expressed complaints about the appearance of cross bite from the right lateral incisor to the second molar, and the asymmetric face according to the shifted mandible to the right. The problem lists from the initial record were as follows: 1. Excessive mandibular growth, 2. Crossbite and dental compensation, 3. Shifted mandible to the right, 4. Occlusal plane tilted transversely by 2.5 degrees, 5. Narrowed maxilla, 6. Crowding.
Orthodontic treatment followed by surgical procedures was performed. After extraction of the upper first premolars, a 022 edgewise appliance was used. After alignment and canine retraction of the upper arch, multiple segmental Le Fort I osteotomy and sagittal split ramus osteotomy were carried out. In the maxilla, the upper arch was divided into 3 segments after the down fracture (Two segments including canine, premolar, and molars, and one segment including incisors), for the purpose of correcting the narrowed maxilla, transverse decompensation, correction of the occlusal plane, and space closing. In the mandible, bilateral SSRO was performed for the purpose of correcting the excessive mandibular growth, and the shifted mandible. In the post-operative period, detailing and finishing were performed, and finally fairly good occlusion was obtained.

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