The purpose of this study is to investigate the injury and reaction of the periodontal tissue caused by bacterial plaque in experimental marginal periodontitis in golden hamsters. The experimental animals were fed on the high sucrose diet (Keyes No. 2000) and vegetables for 15 weeks and 50-52 weeks, respectively. During the experimental period, these animals were permitted to coprophagy three times a week. The control animals were kept on the standard solid diet for the same period. The animals were sacrificed after 15 and 50-52 weeks and the both jaws were removed. These jaws were fixed in 10% buffered neutral formalin and macroscopically, roentgenographically (with softex-ray) and histopathologically examined. Some of them were investigated histochemically for demonstration of acid phosphatase activity, pyroninophilia, nuclear Feulgen reaction and colloidal iron reaction.
The results obtained were as follows;
1. Macroscopically, marked deposition of plaque associated with gingival recession was most frequently observed on the mesiolingual aspect of the mandibular first molar after 15 weeks feeding. After 50-52 weeks feeding, the plaque deposition became much more increased and occasionally involved all mandibular molars. Generally the plaque deposition was more remarkable in the mandibular molars than in the maxillary ones.
2. Roentgenographically, the remarkable reduction in height of the alveolar bone was observed in the mesial region of the mandibular first molar after 15 weeks feeding. The reduction of the alveolar process became more advanced and occurred more extensively after 50-52 weeks feeding.
3. Histopathologically, increased deposition of the bacterial plaque was observed on the mesial surface of the mandibular first molar, and associated with exudative inflammation, deepening of the pocket, apical extension of inflammation in the pocket wall and resorption of the alveolar crest-after 15 weeks feeding. The deposition of the bacterial plaque became much more increased and involved more extensively the mandibular molars, simultaneously progressive marginal periodontitis with advanced destruction of dento-gingival junction and marked resorption of the alveolar process developed after 50-52 weeks feeding. However plasma cell infiltration and macrophage proliferation were minimum both in 15 weeks and 50-52 weeks groups. These findings suggest that immunological response might be not so important for the rapid progression of the marginal periodontitis in the golden hamster.
4. The histopathological and histochemical investigation suggested that the crevicular epithelium can prevent bacterial invasion into subepithelial connective tissue and the preventive potentiality may be attributed to the lysosomal enzyme of the epithelial cells.
5. The present experimental study revealed that rapid increase in bacterial plaque can result in progressive destructive marginal periodontitis without cooperation of considerable immune response.

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The purpose of this study was to clarify the incidental mechanism of diphenylhydantoin (DPH) gingival hyperplasia, especially the role of gingival inflammation in diphenylhydantoin gingival hyperplasia.
As the experimental animals, 90 wister-strain male rats were used. They were divided four groups. Experimental rats in Group A were used as a non-treated control. Experimental rats in Group B were given an intraabdominal administration of DPH. Small cavities were prepared for the maxillar molars in each rat of Group C and Group D so as to induce chronic inflammatory changes for gingiva by the dental plaque. Experimental rats in Group B and Group D were administered DPH for 7 days, 14 days, 28 days, 56 days and 84 days respectively. These experimental rats were examined macroscopically and histologically. It was possible to reproduce the macroscopical and historogical appearance of DPH gingival hyperplasia in rats receiving DPH and accumulating of no dental plaque didn't obvious gingival hyperplasia. Analysis of these results reveals that inflammation of gingiva was considered to be one of the causative factors of DPH gingival hyperplasia.

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The process of collagen phagocytosis and degradation by human gingival fibroblasts were studied in vitro by means of electron microscopy and histochemistry.
In an attempt to demonstrate the phagocytic nature of intracytoplasmic vacuoles, monolayer cultures of human gingival fibroblasts were incubated with collagen fibers for 3 to 6 days and were observed with an electron microcope. Some samples were examined at the ultrastructural level for acid phosphatase activity.
The following results were obtained:
1) Electron microscopy demonstrated collagen fibrils in numerous intracytoplasmic vacuoles in the cells.
2) The vacuoles in fibroblasts cultured for 3 days contained an electron-lucent matrix, whereas those in cells cultured for 6 days frequently contained an electron-dense matrix.
3) Some of these structures containing collagen fibrils showed a positive acid phosphatase reaction.
These results strongly suggest that the intracytoplasmic vacuoles are phagosomes and the phagocytosed collagen fibrils are digested by lysosomal enzymes.

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Secretory IgA and serum IgA in human inflammatory gingiva were demonstrated by immunopathological observation. Secretory IgA localized in the dental plaque, on the surface of gingiva, in the interspace of gingival epithelium and partially in the cytoplasm of gingival epithelium whereas serum IgA existed in all portion of gingiva.
From above results, it was concluded that secretory IgA prevented oral bacterial invasion to the periodontal tissue by coating to them, and serum IgA raised bacterical lysis by complemental activation of thealternate pathway or enhanced phagocytosis of PMNLs.

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The localization of fibronectin in the human inflamed gingiva was demonstrated by a immunofluorescent technique which used monoclonal antibody by product of a hybridoma formed by the PEG fusion of the mouse myeloma PX×63 Ag8 and splenocytes from a BALB/c mouse immunized with human muscle myoblasts. The fibronectin was dectected in the cytoplasm of gingival epithelial cells fibroblasts or fibrocytes, endothelial cells, on the basement and collagen bundle, in the space of collagen bundle, and inflammatory exudates. From above immunopathological observation and histopathological study of gingival tissue, it was suggested that the function of fibronectin was correlated to generate gingival tissue by to promote and induct the proliferation of fibroblasts or epithelial cells.

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The investigations relating to humoral and cell-mediated immunity were carried out with 6 participants in a 3 week experimental gingivitis program. At the beginning of the experiment immediately, 1 and 3 weeks after oral hygiene withdrawal and 1 week after oral hygiene reinstitution, the bacterial plaque accumulation and the gingival inflammation were assessed prior to the gingival fluid measurement and blood taking. The effect of plaque accumulation upon the antibody forming cells (PFC) was examined using modified haemolytic plaque assay. The cytotoxicity of PBL to chicken erythrocytes were assessed using a modification of the standard ⁵¹Cr release assay. Serum 1gG and IgM concentrations by single radial immunodiffusion, and serum antibody titers to plaque antigen by haemagglutination test were evaluated, respectively.
In conclusion, the number of PFC and the cytotoxic activity in the plaque accumulation subjects were significantly increased compared with those in the subject with healthy gingiva. However, no significant differences in the concentrations of serum IgG and IgM and haemagglutinating titers to plaque antigen between two groups were observed.

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The chemotactic factors in the inflamed gingival tissues from severe periodontal patients were identified by the biochemical analysis. Degree of contribution to chemotactic activity of each factor identified in each case was determined by removing one of chemotactic factors and by blocking receptor of cell surface.
The results were as follows:
1) High chemotactic activities to PMN's and macrophages were found in the gingival tissues from severe periodontal patients as compared with clinically healthy tissues.
2) Chemotactic factors were separated from gingival tissues with high chemotactic activities and were analyzed, and it was found that chemotactic activities were generated by. IgG-derived factor and by collagen degradation products.
3) As a result of identifing chemotactic factor in each case, high chemotactic activities were found in the factors derived from immunogloblin, bacteria and collagen degradation products, but it wasn't uniform.

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The aim of this study is to observe the oral hygine status in the factory which had the common factors in the daily life and working.
The 203 persons were abstructed at random from the workers (152 males and 51 females).
The items of survey are the Pl. I., the G. B. I., the furcation involvement and the tooth mobility.
The results were as follow.
1. The plaque index showed no difference statistically between males and females. Molar region on the upper jaw showed on the lot of plaque deposition, above all, distal and lingual parts of the tooth.
2. The gingival bleeding index showed no difference in statistically between males and females. From 40 to 50 age persons showed on statistically significant (p<0.05).
3. The periodontal pocket also showed on the no difference between males and females, but increased on the advanced ages.
4. The furcation involvement appeared on the first molars in both jaws, but lower jaw recognized highly frequency compared with upper jaw.
5. The tooth mobility appeared on remarkably the anterior areas in the both jaws, increased on the advanced ages.
6. The gingival bleeding index and probing depth showed on the positive correlation (r=0.56).

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The purpose of the present study was to evaluate the treatment effect of coronal reshaping (occlusal adjustment) by recording the sounds of teeth impact in the periodontally diseased patients with trauma from occlusion.
The results are summarized as follows:
1. In evaluating the effects of coronal reshaping, the sounds of teeth impact were recorded accurately and objectively.
2. The sound of the optimal teeth impacts in 2 subjects with normal dentition was shown in monophasic (single) and compact wave, and its duration was less than 10msec.
3. In one of 4 patients with periodontitis, the sounds of teeth impact in diphasic (double) waves before coronal reshaping was transformed into monophasic wave after coronal reshaping. The sound durations of 4 patients ranged from 11.0 msec to 19.2msec before coronal reshaping. However, they decreased in the range of 8.3-12.2msec 3 months after coronal reshaping in 3 patients. On the other hand, one subject showed an increase of duration to 16.8msec.

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Furcation involvement has been reported to lead poor prognosis because of its complicated morphological bases. Many reports have been made on the anatomical characteristics of molars intending to improve the prognosis.
In the present experiment, 54 extracted mandibular first molars were used to find the anatomical characteristics and their mutual relationships, from the periodontal point of viewing, aiding in the diagnosis of furcation involvement.
As a result, buccal grove was found in 100%, lingual groove in 96.3%, buccal cervical enemel projection in 68.5%, lingual enamel projection in 33.3% among mandibular first molar teeth examined. Root fluting was seen more frequently and more distinctly on the furcation side of the root than on the other side of the root. Bifurcational ridge was found in 75.9%.
There were mutual relationships between some of the less important characteristics, but as far as the coronal and the root structures are concerned, mutual relationships which might be able to regard as a diagnostic criteria in the daily periodontal practice were failed to found.

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The purpose of this study was to determine the alveolar bone resorption of 437 high school students of 15 years old in Tokyo, Japan. The roentgenographic examinations on bite-wing method were performed about mesial and distal areas of maxillary and mandibular first molars.
Alveolar bone resorptions exceeding 2mm from cement-enamel junction (CEJ) were found at 41 areas of 37 persons. This means bone resorption was occurred at 8.5 per cent of 15 years old students and 1.3 per cent of total mesured points.
It was observed that vertical resorptions were more frequent in upper and mesial areas of first molars.
The statistical difference was found (p<0.05) between the bone resorption group and the normal group in regard to the mean of Gingival Index.

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Because alveolar bone resorption is considered as one of the leading symptoms of the inflammatory periodontal disease, the regeneration of the bone after treatment is of a primary concern to peroidontists.
A case of a boy in which resorption and regeneration of the bone took place within a short period of time was encountered at the authors's clinic. The patient is a 13 years old boy who has been administered Diphenyl-hydantoinate for the treatment of epilepsy since the age of 8. The bone destruction was suddenly noted on the panoramic X-ray films taken for regular check purposes, starting from the inter-radicular space to the distal root of the right mandibular first molar.
Eight months after the first visit, radiograph revealed the nearly complete fill of the bone defect. The therapy performed during this period was an initial treatment of periodontal tissue including plaque control, scaling, occlusal adjustment and restoration of caries cavity of the right mandibular first molar.
The possible explanation of the onset of bone destruction and regeneration was discussed.

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The clinical effect of Acess-A on gingivitis and marginal periodontitis was determined by a double blind method using an inactive placebo as a control. The results are as follows:
(1) Total clinical findings, symptoms antoanalyzed by patients and observations by physicians in charge, indicated a trend that Acess-A possessed better improvement than the control.
(2) In case of main clinical findings, the observations by physicians in charge such as redness, swelling, bleeding, and pus discharge, a significant improvement (p<0.05) by Acess-A was confirmed 4 weeks after the initiation of pasta application in effective percentage.
(3) Significant improvements in recoveries of oral feeling autoanalyzed by patients and of dental calculus, redness, swelling, and bleeding observed by physicians in charge, were recognized with Acess-A in improvement rate.
(4) In order to reduce 50% of the observations in redness, swelling, and bleeding, Acess-A and placebo required 3-4 weeks and 4-7 weeks, respectively.
(5) No remarkable side effect was observed in both Acess-A and placebo.

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