Nihon Kyosei Shika Gakkai zasshi = The journal of Japan Orthodontic Society最新文献

The form of dento-orofacial complex and masticatory muscle function of monozygotic twins with Duchenne type muscular dystrophy were investigated. They had no environmental difference. Morphological analysis were performed on the dental casts and cephalograms. EMG recordings were derived from the bipolar surface electrodes on the masseter muscle and the anterior belly of digastric muscle on the left side. Each consisted of the data for three years. Results obtained are as follows: 1) Based on the average data, these patients showed an elongated dental arch in the maxilla and mandible, which might be caused by enlarged tongues. There were little difference in the tooth and dental arch sizes between them. 2) Cephalometric findings indicated that the elder brother showed a clockwise rotation of the mandible with larger gonial angle than the younger brother. Both of them showed a larger gonial angle based on the mean values. 3) Analysis of EMG recordings revealed an elongated silent period induced by teeth tapping and chin tapping, and a variable masticatory rhythm compared with that of normal sample. Moreover an annually increased imbalance between masseter muscle and digastric muscle was evident, which were parallel to the change of the blood creatine kinase value. Differences in the form and function of orofacial complex between them might be caused by their polygene heredity and the large size of DMD gene (XP 21).

The purpose of this study was to investigate the effects of localized thermal enhancement on new bone formation in rats. Sixty four male Wistar rats of 52-day old were used as the experimental animal. The sagittal suture of the rat was expanded with the force of 75 g by means of an expansion appliance. After the force application for 2 days, the expansion appliance was fixed with a composite resin. The infrared ray was applied to the expanded sagittal suture for 20 minutes a day and the temperature, just above the sagittal suture, was measured with a biothermometer. The local heat was given for 5-days. The experimental animals were divided into 4 groups based on the increase of temperature: Control, 1 degree C, 2.5 degrees C and 4 degrees C groups. The sagittal suture of each rat was examined by both light and fluorescent microscopies. And histochemistry for acid phosphatase and tartrate-resistant acid phosphatase (TRAP) were performed. The results obtained were as follows: 1) In control and 1 degree C groups, little reaction of acid phosphatase and TRAP were observed in the sutural tissue except for the marrow and the neighboring area of the capillary vessels. 2) In 2.5 degrees C and 4 degrees C groups, an increased absorptive area of the bone and an active reaction of acid phosphatase were found in the sutural area. 3) In only 1 degree C group, an increased new bone formation was evident in the sutural area. Results obtained suggested that the degree of new bone formation depended on the temperature of tissues concerned.

The purpose of this study is to clarify the long-term dentofacial changes after sagittal splitting ramus osteotomy in skeletal Class III patients, and to study the factors involved to find its countermeasures. For this purpose we used the radiographic cephalograms in 16 patients (13 females and 3 males) observed for more than five years after surgery. We measured the postoperative changes in the position of Pogonion and the inclination of maxillary and mandibular incisors. The results were as follows: 1. Pogonion was retruded 9.3 mm on the average by surgery. In the period from the removal of intermaxillary fixation to one year postoperatively Pogonion slipped forwardly and upwardly (average; anteriorly 1.0 mm, superiorly 0.8 mm). In the period from one year postoperatively to the time of the final observation Pogonion slipped to a downward direction. 2. No correlation was found between the amounts of vertical displacement by surgery and postoperative vertical changes of Pogonion. On the other hand, a high correlation was found between the amounts of mandibular setback and the forward displacement of Pogonion. 3. Mandibular incisors were tipped labially by preoperative orthodontic treatments, then maxillary and mandibular incisors moved lingually during intermaxillary fixation. After release of intermaxillary fixation, maxillary incisors moved labially in a small distance. After one year maxillary incisors were inclined slightly in the lingual direction. It is obvious that the position of the mandible and the incisor inclination tend to change even after one year. Because the postoperative changes were small in quantity, we supposed they were mostly caused by occlusal changes. Clinically, occlusal relationship in the incisor area, i.e., overjet and overbite, was maintained to be normal. It was considered that the changes of incisal inclination after release of intermaxillary fixation were of a compensatory or adaptational response to a positional change of the mandible.

To investigate the present state of orthognathic surgery, questionnaires were sent to 30 departments of orthodontics of university dental hospital and 60 departments of oral surgery of university medical hospital. 1. Orthognathic surgery was carried out in 100% of the departments of orthodontics and 91.8% of the departments of oral surgery examined. 2. There was a difference in the number of patients between individual hospitals. 3. Analyses of cephalogram were used in 96% of the departments of orthodontics and 93% of the departments of oral surgery. 4. Pre- and post-surgical orthodontic treatments were carried out in all of the departments of orthodontics. 5. Orthodontic appliances (83.9%) were used in the departments of orthodontics for intermaxillary fixation, while orthodontic appliances (47.8%) and wire splints (49.2%) were used in the departments of oral surgery. 6. It is pointed out that the criterion of orthognathic surgery, treatment objectives on soft and hard tissue, selection of surgical method, adaptability of soft tissue after surgery, relapse, treatment planning of two jaw surgery, and postoperative stability remain to be solved in future.

The purpose of this study is to evaluate the relationships between the sectional forms of the mandible and the craniofacial morphology. Vertical sections were made at the symphysis (SY) and at the second molar region (M2R). Materials were dried human skulls which were measured in three dimensional co-ordinate system. The correlation matrix of 24 measurements was examined in the male and the female. The difference of these measurements between the low angle group and the high angle group of gonial angle was also examined. Results obtained were as follows: 1. Gonial angle was negatively correlated with the height, width, breadth of ramus and the breadth of second molars. SY form was related to the facial height and size of the mandible. On the other hand, M2R form was related to the height, width and breadth of ramus. 2. The differences of measurements between the low angle group and the high angle group of gonial angle were as follows: 1) The ramal height, ramal width, bicondylar width and breadth of second molars in the low angle group were significantly larger than those in the high angle group. 2) The measurements of SY in the high angle group and the low angle group showed no significant difference. 3) The height and area of M2R in the low angle group were significantly larger than those in the high angle group. This study demonstrated that SY form might relate to vertical factors of the face (facial height), the size of mandible and the types of occlusions. On the other hand, M2R form being nearer to the attachment of masseter and medial pterygoid muscles than SY was related to the form of ramus and the gonial angle.

The purpose of this study was to investigate the timing of the formation and eruption of the permanent teeth between Skeletal Class II and Class III malocclusions right before pubertal growth period. Samples consisted of twenty five Japanese girls of Class II and Class III malocclusions, respectively, with Class I girls as a control. Materials used in this study were panoramic X-rays, dental X-rays and intraoral photographs of each sample, all taken at age of 8 years. Lateral cephalometric X-rays, wrist bone X-rays and records of standing height were used to study the craniofacial characteristics and the stage of bone maturation. Results were as follows: 1. Lower teeth formation of Class III group tended to be advanced when compared with Class II group, especially at molars. 2. There was no significant difference between the two groups with regard to the timing of eruption except lower lateral incisors, but eruption of the upper second molar of Class III group tended to be delayed. Results suggested that the skeletal disharmony may be associated with different timing of formation and eruption of the permanent teeth.

This study was undertaken to investigate the desire and consciousness of orthodontic patients and their parents on the content and effect of orthodontic treatment. The subjects were 362 post-treatment patients and 353 of their parents, who answered the questionnaires. The following conclusions were obtained: 1. 49% of the patients and 16% of the parents of the patients thought of giving up the treatment while the patients were under the orthodontic treatment. The main reasons were the discomfort of orthodontic appliances, long treatment period, and the absence from school. 2. 55% of the patients felt uneasy about a change of the occlusion for the worse after removal of the orthodontic appliances, and 60-70% of the patients and parents had forgotten the necessity of the retainer after active orthodontic treatment. 3. Both patients and parents hoped to finish the orthodontic treatment by the end of junior high school. 4. About 50% of the parents preferred the university hospital and about 45% preferred a private dental office which was convenient for attending as an outpatient. 5. About 70% of the patients and parents were satisfied with occlusion after orthodontic treatment, and 33% of the patients and 61% of the parents were satisfied with the orofacial appearance after treatment. 6. About 9% of the patients hoped to keep secret their history of orthodontic treatment. 7. About 35% of the patients and 60% of the parents would recommend people with malocclusions to receive orthodontic treatment. About 80% of the patients would make their own children receive the orthodontic treatment if needed. 8. About 90-95% of the patients and parents were pleased with orthodontic treatment.

It is well known that orthodontic forces induce pain during tooth movement. However there have been few neurohistological studies on sensational periodontal tissue response to orthodontic tooth movement. So we have many unknown problems about reactions of periodontal nerve fibers during tooth movement. The present study deals with the response of nerve fibers in periodontal ligament of rat molar during experimental tooth movement by means of immunohistochemical method for calcitonin gene-related peptide (CGRP). The results obtained in this study were as follows: 1. In control sections, CGRP-immunopositive nerve fibers were observed both around the root apex and in the intermediate region of the periodontal ligament. Although most of those fibers was distributed around the blood vessels, a few nerves were recognized to terminate in the periodontal fibers. 2. At three days after tooth movement, the CGRP-positive nerves gradually increased in number around the blood vessels. After that, the number of CGRP-positive nerves decreased and no difference of distribution of CGRP-positive nerves was observed between the control sections and the experimental sections at seven days. 3. Especially, at three days when active remodeling of alveolar bone was taking place, a few nerve fibers showing CGRP-immunoreactivity were observed to concentrate around osteoclasts or to migrate Howship's lacunae. These findings showed the dynamic changes of CGRP-immunoreactive nerves in the periodontal ligament during tooth movement, and suggested that this reaction of the periodontal nerves might induce pain in patients. In addition to neurotransmitter function, it was supposed that CGRP directly or indirectly effected the cellular elements and surrounding tissues on peripheral organs such as vascular system and osteoclasts.

Normal mastication needs condylar support. Mandibular condyle is thought to be one of the factors which control facial growth. To determine which parts of the face are affected by unilateral complete condylotomy including surrounding connected soft tissues, thirty-nine male Wistar rats, 5 weeks of age, were divided into control, sham treated and experimental groups. The control animals received no treatment, where as the left mandibular condyles of the experimental animals were condylotomized. Soft X-rays of the animals of both groups were taken every two weeks, and all were killed six weeks after treatment. Roentgenografically, it was observed in the experimental animals that a functional condyle-like process generated to fill the condylar space of glenoid fossa. This process was smaller than normal condyle of the control anomals. Furthermore, ANOVA revealed significant differences (P less than 0.01) in some facial structures including facial height as well as mandibular length, which were still affected at six weeks after the surgery. The result of the present investigation suggests that unilateral condylotomy induced the production of a functional condyle-like process and caused some facial deformities.

Concern of patients for dentition and receptivity of orthodontic treatment was studied by a general population questionnaire. Subjects (general population) consisted of elder elementary school boys and girls (157), junior high school (274) and high school students (90) and adults (45) in Tokushima, Kagawa and Kouchi prefectures. Twenty-three questions, previously selected from forty-seven using the Quantification III for orthodontic patients. Furthermore, ten questions were selected from these twenty-three using the same method and categorized into two groups. Each category was given a meaning. Five answers in each category were given marks: a positive answer was 'point one' and a negative one was 'point zero'. Mean points in each category were compared with eight groups according to age and sex. AIC (Akaike Information Criterion) was used for statistical analysis. The following results were obtained. 1. Two categories were independently identified. One had meaning in relation to concern for dentition and other had meaning in relation to receptivity of orthodontic treatment. 2. Orthodontic patients showed significantly higher points than general population for concern and receptivity. 3. Females in each group showed higher points for concern of dentition in general population, but males showed higher points for receptivity of orthodontic treatment. 4. Junior high school and high school students showed significantly lower points in two categories, in addition, males in this group showed lower points in these categories. 5. There were no significant differences between subjects in three prefectures. It is possible for general population to evaluate instructions or education methods for promoting interest in dentition by this study. Orthodontic patients will also be encouraged by the present study to receive orthodontic treatment.