In this study, the effects of treatment of anterior maxillary advancement using distraction osteogenesis were investigated. The subjects were three severe skeletal class III patients who needed surgical orthodontic treatment for mandibular retrusion (one female aged 16 years and 5 months of age, one female aged 28 years and 9 months, and one male and 26 years and 3 months at the initial examination). At the initial examination, extra-oral clinical examination revealed concave profiles and intra-oral examination revealed crowding in the upper arches in all patients. In presurgical orthodontic treatment of the maxilla, anterior maxillary advancement was performed using an intraoral appliance a palatal expansion screw from a few days after the maxillary osteotomy. Lateral expansion was performed simultaneously in one case. Anterior maxillary advancement was performed at a rate of 1 mm of advancement per day for seven to nine days. Data were obtained from maxillary dental casts, profile facial photographs and lateral cephalograms before and just after the completion of expansion. Just after the completion of expansion, the upper incisor edges had moved 4.8-9.1 mm anteriorly. In the patient whose palate was also expanded laterally, the inter-premolar width increased to 6.8 mm. It was found that SNA increased 3.51-5.12 degrees, SNB decreased 1.17-0.31 degrees, NSP-A increased 4.4-5.6 mm and U1-SN increased 7.10-11.17 degrees. Anterior maxillary advancement using distraction osteogenesis resulted in creation of sufficient space in the upper arches to cancel the arch length discrepancies in the upper arches. In addition, the concave facial profiles of all patients improved.

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We previously reported that the prevalence of third molars is not related to antero-posterior dimensions of the mandible but to those of the maxilla. The purpose of this investigation was to clarify the correlation between the existence of third molar germs and sagittal maxillo-mandibular jaw dimensions. The existence of third molar germs in hemifacial microsomia (HFM) was examined to compare the presence of third molars on the affected side of the mandible and the normal side. The subjects were 69 HFM who had been treated at the Orthodontic Clinic of Hokkaido University Dental Hospital and who were less than 15 years old at the first examination. Panoramic radiographs that had been taken at the first examination and several years after the first examination were used as materials. A total of 391 patients who had been treated at the same hospital and who didn't have congenital deformities were used as a control group. The percentage of patients in the HFM group who did not have even one was significantly higher than that in the control group. There was no significant difference between prevalences of third molars on the affected side and normal side in the HFM group. These results suggest that agenesis of the third molar is related to the onset of HFM.

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High-pull headgear and the combined activator-headgear appliance are commonly used for skeletal class II, long-face type malocclusion. The purpose of this study was to compare the treatment effects of the high-pull headgear and the combined bionator-headgear appliance for growing patients with skeletal class II, long-face malocclusion, using cephalometric analysis of twins. The twins were 7years, 6months of age and diagnosed as skeletal class II, long-face. The elder brother was treated with the combined bionator-headgear appliance for 1 year and 11 months. The younger brother was treated with high-pull headgear for 2 years and 5 months. Comparing the cephalograms obtained from before and after treatment indicated the following. Both cases showed the inhibition of anterior growth of the maxillary. The mandibular plane angle decreased and the ratio of upper to lower facial height was mostly maintained in the two cases. Upper molar eruption was inhibited in the two cases and the combined bionator-headgear appliance inhibited eruption of the lower molar. ANB angle was improved 1.9° in the high-pull headgear case and 2.0° in the combined bionator-headgear appliance case due to the restriction of maxillary growth, the clockwise mandibular rotation, and the increase of mandibular length. No differences were found in the increment of the mandibular length. These results indicated that both appliances are very effective for correcting skeletal class II, long-face malocclusions in the mixed dentition. There are little differences between treatment effects except that the combined bionator-headgear appliance inhibited the lower molar eruption more than the high-pull headgear.

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Two types of protectors (paper type and pressed type) were developed to prevent pain that orthodontic patients fitted with multibracket appliances experience when playing a wind instrument. The effectiveness of these protectors was tested on seven orthodontic patients who played a class A instrument (e.g., trumpet) a class B instrument (e.g., clarinet) or a class D instrument (e.g., flute) according to Strayer's classification and on two control subjects (one who played the trumpet and one who played the clarinet). The following results were obtained: 1. The protector should be used on the upper and lower anterior teeth when playing a class A instrument and on the lower anterior teeth when playing a class B or D instruments. 2. Both protectors were found to be effective for preventing pain when playing class B or D instruments. The paper-type protector could be used when playing a class A instrument. The pressed-type protector could be used either on the upper or lower teeth but was difficult to use on both upper and lower teeth when playing a class A instrument. 3. A class A instrument produces pressure acting on both upper and lower teeth in the lingual direction, and a class B instrument produces pressure acting on upper anterior teeth in the labial direction and on lower anterior teeth in the lingual direction. The protectors used in this study appear to be beneficial for orthodontic patients who play certain classes of wind instruments.

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A questionnaire survey was carried out to clarify the points regarding metal allergy that attention should be given to when treating orthodontic patients. The subjects were 7 orthodontic patients (1 male and 6 females; mean age, 21.3 years) who had been diagnosed as having metal allergies by patch tests. The following results were obtained. 1. Nickel was the most frequently identified metal showing a positive reaction in patch tests (in half of the patients). Since nickel is frequently used in orthodontic treatment, care should be taken over the selection of material when treating orthodontic patients with metal allergies. 2. All of the patients had other allergy symptoms. Thus, taking detailed histories may lead to the discovery of metal allergies in patients who are not aware of such allergies. 3. Four of the seven patients had symptoms of metal allergy caused by earrings and other such ornaments. Since many orthodontic patients are young women, taking detailed histories and conducting careful observations are important.

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We previously reported, based on the results of questionnaires, that facial features of Japanese with high scores of dissatisfaction were the nose, eyelids, cheekbones and teeth. The feature with the highest score of dissatisfaction was cheekbones. The purpose of the present study was to elucidate the morphological characteristics of cheekbones and soft tissues in orthodontic patients who have various skeletal malocclusions. The selected subjects were 64 females aged from 16 to 56 years (average age: 24 years and 5 months). Measurements were made using computed radiography cephalograms of the angles of the SNA, SNB, ANB, U1 to FH and distances from the midfacial line, pronasale, subnasale and edge of the upper incisor to the zygomatico-alveolar crest, nasal notch and Y line. The following results were obtained: 1. The antero-posterior positions of the pronasale, subnasale and midfacial line were significantly related to the SNA and SNB. 2. The sagittal position of the edge of the upper incisor affected the sagittal position of the midfacial line. 3. The antero-posterior position of the midfacial line did not depend on ANB. 4. The thicker the soft tissue from the zygomatico-alveolar crest or nasal notch to the midfacial line was, the greater was the distance from the zygomatico-alveolar crest or nasal notch to the pronasale.

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The critical pathway helps to organize patient's care and eliminates variations created by doctors' different preference. In order to establish the critical pathway, we gathered and analyzed data focused on the length of the treatment in each step. The following results were obtained. 1. An average length of the treatment in each step was a. 1.8 mos from the initial examination to diagnosis b. 19.8 mos for the pre-surgical orthodontic treatment c. 5.0 mos for a jaw surgery including d. 11.0 mos for the post-surgical orthodontic treatment 2. The pre-surgical orthodontic treatment varied widely and took the longest time 3. The extraction cases (average; 22.0 mos) significantly needed longer time than the non-extraction cases (average; 16.7 mos) in the pre-surgical orthodontic period These data suggest that the application of the critical pathway to the pre-surgical orthodontic treatment would be more effective and two or more different critical pathways should be established for this period.

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A questionnaire survey was carried out to determine the types of inconvenience felt in daily life due to oral injuries caused by fixed orthodontic appliances and to determine the percentages of orthodontic patients who feel such inconveniences and who visit emergency clinics for treatment of the oral injury as well as the relationship between these percentages. The subjects were 64 orthodontic patients who had been fitted with fixed appliances (male/female ratio, 1:3.6; mean age, 23.5±6.2 years; mean treatment period, 2.2±1.3 years). The following results were obtained: 1. There was a greater tendency in male patients than in female patients to either constantly feel inconveniences in daily life due to oral injury or to not feel any inconveniences at all. There was also a greater tendency in male patients than in female patients not to visit emergency clinics for treatment. 2. There appears to be a correlation between the feeling of inconvenience in daily life due to oral injury and visiting an emergency clinic for treatment. 3. The main factors causing the feeling of inconvenience in daily life were difficulty in speaking, irritation and pain. 4. More than half of the patients who did not visit emergency clinics for treatment of oral injury probably have negative or indifferent feelings regarding treatment for the oral injury.

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