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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.

The present study was attempted to establish the model of transseptal fibers in vitro to clarify the remodeling mechanisms of the fibers during orthodontic treatment. Human premolars were transversally cut. The thickness of films was 150 microns and a pair of dental rings was placed at intermediate of 500 microns in tissue culture dishes. Human gingival fibroblasts were seeded in these dishes and cultured. Culturing of these cells were changed at 1, 5, 10 and 20 days and used to histological observation. The following results were obtained: 1. It was observed that human gingival fibroblasts and fibrillar materials oriented approximately the surfaces of sliced teeth and extended the process of cells along the direction from sliced teeth to another one. The bridges of cells and fibers between two sliced teeth were completed after 10 days culturing. 2. The fibrillar materials were examined by TEM and bundles constructed from banded fibrils which each band was 60 nm in diameter. The red fibers were stained with Van Gieson's stain method and so many red fibers filled in the space between the two sliced teeth. This suggests that the most of fibrillar materials were collagen fibers formed from human gingival fibroblasts. The structural materials were assumed to be resembled to transseptal fibers in vivo. This culture system is usefull to study the remodeling mechanisms of transseptal fibers in tooth movement.

The present investigation has been attempted to clarify the remodeling mechanisms of transseptal fibers during mechanical retention periods. Orthodontic forces of 25 gm and 150 gm were respectively applied to upper molars of rats for 10 days and retained mechanically. Retention periods were 10, 30 and 60 days. The trend of transseptal fibers after these retention periods was observed by the methods of histology and histochemistry. Histological study was observed rearrangement of fibrous tissue by light and electron microscopy and histochemical one was observed acid phosphatase activity. The following results were obtained: 1. Very little was observed about the rearrangement of transseptal fibers by the orthodontic force applied for 10 days. 2. The mechanical retention was kept longer, stretched transseptal fibers were slowly restored to original shape. This means transseptal fibers were gradually rearranged. 3. The collagen containing fibroblast and fibroblast characterized by abundant rough endoplasmic reticulum and Golgi complex were ultrastructurally observed. 4. The reaction of ACPase activity in some fibroblasts can be observed. These results suggest that transseptal fibers were rearranged during mechanical retention periods and that fibroblasts were engaged in this remodeling by synthesizing and degrading collagen fibers.