This study was pemformed to evaluate the influence of 6 different solutions to the reattachment on the experimentally exposed Cementum in male rats. A rubber strip was threaded in the distal part of the mandibular first molar. Then, at the removal of the rubber after two days, 6 solutions were applied to the exposed root surface by a needle. Six solutions were composed of (1) Blood, (2) Collagenase, (3) Lipopolysaccharide, (4) Whole Saliva, (5) Calcium-chloride and (6) E.D.T.A.. Those mandibulars were resected for histological evaluations after one week from the application. The results were as follows.
1) Control specimens not applied any solutions showed reattachment without denudation of the root surface, however existing long junctional epithelium which was not seen in normal rats.
2) In the experimental groups of (1), (2), (5) and (6), any particular differences were shown, compared with the control specimans.
3) In groups (3) and (4), some of them showed a slight but distinct denudation of the root surface.

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The purpose of this study was to investigate the influence of periodontal disease on masticatory function and the effect of periodontal therapy on it. Nine patients with mild to advanced periodontitis were. examined about masticatory efficiency, maximum bite force, occlusal platform area, width of keratinized gingiva and the position of gingival margin in addition to routine clinical examinations. Masticatory efficiency was measured by modified Ishiwara's method on right and left halves of dentitions with raw rice as test food. After the periodontal treatment, these measurements were performed again on five patients.
The results were as follows:
1) The average scores of Plaque Index, masticatory efficiency and maximum bite force were 1.54, 86.3% and 29.1Kg respectively.
2) Before treatment, there was a significant negative correlation between masticatory efficiency and bone resorptioq (P<0.01), tooth mobility (P<0.01) and pocket depth (P<0.05), on the other side a significant positive correlation between masticatory efficiency and maximum bite force was found.
3) After periodontal treatment, average masticatory efficiency increased (34%) but this change was not statistically significant (P>0.05).
4) After treatment, increase of maximum bite force and occlusal platform area was found, and decrease of tooth mobility, bone resorption, Gingival Index score and pocket depth was observed, and gingival margin was apically shifted. Above changes were all significant at the 1% level of confidence.

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This study was performed to use 12 teeth from 11 patients that were indicated to treat with metal crown restration. Each tooth was temporarily set 2 different shaped metal crowns for 4 weeks, one of these was made with under-contoured proximal surface and the other had over-contoured proximal surface. One week after temporarily setting the crown, the plaque accumulated on the crown was stained with disclosing solution and photographed with standerdized method. After this procedure, plaque on the proximal surface was removed with interdental cleaning devices, and the remained plaque stained and photographed with the same manner. The accumulation of plaque and the removal effect of plaque by interdental brush or dental floss were studied quentitatively at 1 week intervals on the color photograph. The following results were obtained:
1) The accumulation of plaque on the both shaped crowns could not be found significant differences.
2) It was shown that cleaning effect of dental floss was more effective on the distal surface than the mesial surface.
3) Using 3 strokes of both interdental cleaning devices, 90% of plaque was removed.
4) Plaque accumulated on the crown margins of under-contoured restration was more removed with interdental brush than with dental floss.

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The permanent diabetes in the ICR mice was produced by an intraperitoneal injection of 80μg/g streptozotocin (NSC-37917). The periodontal tissues of the six-month-old mice with streptozotocin hereditary diabetes, that were the seventh generation of the above ICR mice, were investigated histopathologically and histochemically.
1. The ridges of the gingival epithelium was irregular and hyperplastic. The acid phosphatase activity decreased in this epithelium.
2. In the gingival lamina propria, dilatation and hyperplasia of blood vessel were observed. There was an increase in number of the mast cells and a marked release of granules from these cells.
The acid phosphatase activity increased in the lamina propria.
3. In the periodontal membrane, the arrangement of the fibers was irregular and both acid and alkaline phosphatase activities increased.
4. With an appearence of the osteoclasts, the alveolar bone showed an osteoclastic resorption on its surface, and the β-glucuronidase activity increased in the osteoclasts.

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Contents of citric acid, calcium and phosphorus were studied in the serum and bones (maxillary alveolar, mandibular alveolar and femoral bones) of alloxan diabetic rats at 5, 10 and 15 weeks after injection of alloxan. Citric acid was measured by the method of Hori et al, calcium by atomic absorption spectroscopy, and phosphorus by the method of Lowry et al.
The following results were obtained:
1. The citric acid contents in the serum were significantly higher in the alloxan diabetic than the control rats (P<0.05), but the calcium and phosphorus contents were not statistically significant between the alloxan diabetic and the control rats.
2. The citric acid contents in the alloxan diabetic rats were significantly higher at 5 weeks in the maxillary and mandibular alveolar bones and at 5 and 15 weeks in the femoral bones, as compared with those of the control rats (P<0.05).
3. The calcium and phosphorus contents in the maxillary alveolar, mandibular alveolar and femoral bones did not differ from those of the alloxan diabetic and the control rats.
4. Throughout the experimental period, there was no histological difference in the maxillary and mandibular alveolar bone between the alloxan diabetic and the control rats.

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The effects of fluoride on the enzyme activities of the periodontal tissues of rats, that received either 50ppm NaF or 100ppm NaF in the drinking water for a year, were investigated histochemically. The activities of the enzymes studied were alkaline phosphatase, acid phosphatase and β-glucuronidase.
1. Alkaline phosphatase activity decreased in the periodontal tissues of both NaF 50ppm and NaF 100ppm groups, as compared with that of the control group. There was little difference in acid phosphatase activity among the periodontal tissues of the three groups (the control, NaF 50ppm and NaF 100ppm groups). The activity of β-glucuronidase almost disappered in the periodontal tissues of both NaF 50ppm and 100 NaF ppm groups, whereas the marked activity of the same enzyme was recognized in the periodontal tissues of the control group.
2. Alkaline phosphatase activity decreased in the bone of the body of the maxilla of both NaF 50ppm and NaF 100ppm groups, as compared with that of the control group. Acid phosphatase activity in the bone of the body of the maxilla was almost the same in both control and NaF 50ppm groups, but the activity decreased in the similar area of NaF 100ppm group.

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To establish an experimental model of the occlusal trauma of first molar in germ-free mice, crowns of 2nd and 3rd molars were cut or ground.
Histopathological examinations of the periodontal tissue were performed in one day and up to 56 days after the operation.
The results were as follows:
1. The irregular arrangement and the atrophy of the periodontal fibers, the decrease of the cellular components, as well as the destruction of the alveolar bone were the typical changes observed.
2. More consistent results were obtained in the group of mice that had cutting procedure of the crowns than those that had grinding procedure.
3. Pathological or senile changes were not found in the gingival, periodontal and alveolar tissue in control animals.

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The purpose of this study was to know how the crown-root ratio affects periodontal tissue as a predisposing factor of periodontal disease.
Eight hundred and forty teeth which had been previously extracted because of periodontal disease, 549 teeth extracted as control from 65 cadavers, aged from 17 to 83, 62 males and 3 females were used.
Crown and root lenghths were measured and the anatomical crown-root ratios were calculated for incisor, canine and premolar teeth except molars.
The teeth were divided into 7 groups (1|1, 2|2, 3|3, 54|45, 21|12, 3|3, 54|45) for statistical analyses.
The following results were obtained from the statistical analyses of the data.
1. The roots of the extracted teeth because of periodontal disease were significantly shorter than those of control except lower canines.
2. The crown-root ratios of the extracted teeth because of periodontal disease were significantly larger than those of control in the following groups, 1|1, 3|3, 54|45, and 54|45.
The results of our study may indicate that the unfavorable crown-root ratio acts as a factor of occlusal trauma and contributes to periodontal bone destruction, early mobility, and subsequent teeth loss in process of periodontal disease.

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The purpose of this study was to investigate the effect of chewing of gum, an extremely common habit, on bad breath. In this study, to estimate the effect of chewing of gum on bad breath gas chromatograph equipped with flame photometric detector and organoleptic perception technique were applied.
The results were as follows
1. Using gas chromatograph equipped with volatile sulfur compounds were detected from the subjects with bad breath
2. By chewing of gum volatile sulfur compounds were reduced significantly for 1 hour at least, and by organoleptic perception technique bad breath was not perceived for 1 hour
3. The effect of chewing of gum base on bad breath last about 20min. after that the concentrations of volatile sulfur compounds rapidly returned to the pre-chewing conditions
4. From this study significant effect on bad breath was observed by chewing of gum

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Changes in alveolar bone following various periodontal surgeries were studied. The 55 surgical treatments were performed on 16 patients with periodontal disease. Radiographs were taken at the surgical regions by using the standardized X-ray technique. The interdental bone areas were measured on the X-ray films. The measurements were followed up to a period of three to four years. At the same time, various periodontal indices were also recorded. In addition, when a flap operation was performed, the type of bone defect was evaluated and recorded.
The results were as follows:
(1) Loss of alveolar bone was observed until 2 months after surgery and then new bone formation was observed,
(2) Among various periodontal surgeries, flap procedure demonstrated most bone loss post-operatively, gingivectomy showed moderate bone loss but following gingival curettage, apposition of new bone was observed 1 month after operation.
(3) Among various pattern of bone defects, the areas with horizontal bone loss showed an increase in bone apposition after 3 months post-operatively but in contrast the defect with one wall showed resorption of alveolar bone.
(4) The changes in alveolar bone were not correlated to the plaque index 10 months after operation, however 3 or 4 years postoperatively, the correlation between these two factors was significant statistically.
(5) The changes in the alveolar bone observed at an interval of 6 months and 3-4 years were found to be independent of the changes in the depth of periodontal pockets.
(6) The lamina dura re-appeared rapidly between 3-6 months post-operatively and then the rate of appearance levelled off at about 50%.

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In an attempt to determine how the degree of roughness of the polished dentin planes would be affected by several factors under root planing, quantitative measurement was made statistically.
The results obtained were as follows:
1) On the roughness of the dentin surface under hand scaling, a statistical analysis showed that strokes proved to the largest affecting factor, followed by applied force.
2) On the roughness of the tooth surface under two different types of ultrasonic sealers, it was found that ODONTOSON resulted in more rough rather than CAVITRON.
In ODONTOSON, a statistical analysis showed that strokes proved to the largest affecting factor, followed by applied force, and the interaction of applied force and strokes.

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