It has been reported that, in patients of the chronic marginal periodontitis, degenerate changes are found in their teeth and that thetreatment of periodontal teeth in which progress has taken place tends to be less successful. In particular, a poor prognosis is known in the amputation of vital pulps.
The author and his associates have already reported on the identification of phospholipids constituting the dental pulp. In the present study, the author was concerned with quantative measurements of phospholipids in the periodontal and normal teeth in an effort to find out the metabolic change due to the chronic marginal periodontitis.
As a result, the author arrived at the following conclusion.
1. The dental pulp of man consisted of sphingomyelin, phosphatidylserine, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, diphosphatidylglycerol, Lyso-phosphatidylcholine and Lysophosphatidylethanolamine.
2. As regards control teeth, 19 in number, and those in which evidence of the periodontitis was present, the largest amount of pulp-constituent phospholipids was phosphatidylcholinc, followed in order by phosphatidylethanolamine, sohingomyelin, diphosphatidylglycerol, phosphatidylinositol and phosphatidylserine.
3. In terms of different age groups, there was observed a trend of increased phospholipids in the control and periodontal teeth in proportion to chronological ages.
As regards periodontal teeth having root canal rami, however, this trend was not confirmed.
4. As compared with controls, the periodontal teeth and those having periodontal pulps with root canal rami were found to contain a somewhat smaller amount of phospholipids.

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Streptococcus mutans (PK1, GS5, HS6, Ingbritt m type, N type, and 102-2), Neisseria and Streptococcus salivarius were examined for their growth in liquid media, their adherence to the surface of the glass and their agglutination reaction in the presence of different carbohydrates. They were then inoculated orally into germfree JCL: ICR mice which were fed on diets with or without containing 50% different carbohydrates. Their growth on the surface of the tooth and their ability to form dental plaques were compared with their in vitro properties of growth and adherence. The following results were obtained.
(1) All the strains tested showed an abundant growth when cultivated in Trypticase Yeast (T. Y.) medium fortified with sucrose, glucose or fructose, but no growth was observed when cultivated with medium containing no carbohydrates. (2) All the strains except S. mutans N type, showed the adherence of organisms to the glass wall of the culture bottle that contained the TV-broth fortified with sucrose. No adherence were observed with medium that contained other carbohydrates. The agglutination of organisms was also observed with all the strains when tested in the presence of sucrose but not with glucose or fructose. However, S. mutans PK1 showed the most potent ability in both reactions among the strains tested. (3) Among those tested for the infection of the germfree mice, S. mutans PK1 was found to exhibit the most potent capability to form dental plaques. The mice, when inoculated with the PK1 strain and fed diets containing 50% sucrose, showed the following mean staining indices of plaque of 7.3, 26.1 and 59.2 at 2nd, 4th and 8th week, respectively. While the staining indices of the uninfected mice ranged between 1.4 and 2.8 In the mice fed with diets containing 50% glucose or fructose, PK1 grew well as did the organisms in mice fed with sucrose-diets but showed much less indices of plaque formation. (4) S. salivarius also grew well on the tooth surface in germfree. mice but showed only a slight plaque formation to the similar levels as those in uninfected mice even when fed with 50% sucrose diets. (5) S. mutans 102-2 strain, which exhibited the carbohydrate-dependent growth in vitro and the adherence properties similar to those of PK1 strain, did not grow well on the surface of the tooth and so produced a very low plaque index either when fed diets with sucrose or without sucrose. This phenomenon suggested that this strain may be genetically unable to grow in JCL: ICR mice.
In conclusion, a strain (S. mutans PK1) which can firmly adhere to the surface of the glass in the medium containing sucrose could grow on the surface of the tooth and form thick dental plaques on it. In contrast, a strain (S. mutans 102-2) which can also firmly adhere to the surfaces of the glass could not grow on the tooth and therefore showed no potent capability to make a plaque. S. salivarius which can adhere to the glass and produce levan but not glucan could grow on the tooth but showed no potent sucrose-dependent plaque formation. Thus, the experimental model of plaque formation by S. mutans in the germfree mice presented in this report may provide us a valuable method to evaluate the role of the dental plaque on periodontal diseases and on dental caries.

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This study was made on the changes of the two-wall osseous defect and the depth of the inflabony pocket induced with lower first molar teeth of the adult dog. In addition to this, changes of lysosomal enzyme activity in pocket exudate and gingival tissue on diurnal reparation of the inflabony pocket were observed.
The results obtained were as follows:
1) Inflabony pocket was recovered to about 4mm depth in 3 weeks after operation.
2) In about 3 weeks the surface texture of gingiva turned to preoperative status.
3) The gingiva showed a tendency of a slight recession with the healing of inflamation.
4) From the X-ray finding clearly new bone formation was observed at root apex in 2 weeks after operation and appreciable reparation in 3 weeks.
5) In inflabony pocket exudate, N-acetyl-β-glucosaminidase and β-galactosidase showed highest activity on the seventh day but β-glucosidase was highest on the third day, acid phosphatase and alkaline phosphatase were highest on the fifth, and β-glucuronidase had little difference in activity between the third and fifth days with a slight decrease on the seventh day.
6) In gingiva, acid phosphatase, β-galactosidase, β-glucuronidase and alkalin phosphatase showed a highest activity on the fifth, and β-glucosidase had no difference in activity between the third and fifth days with a decrease on the seventh day. And N-acetyl-β-glucosaminidase showed higherr values on the fifth and seventh days than on the third.
From the above it was made clear that the activity of lysosomal enzyme in the inflabony pockets exudate and the gingival tissue became higher diurnally from the fifth to the seventh day with the healing of inflammation. Especially acid phosphatase was remarkably increased in activity on the fifth day.

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The present histochemical study was made to clarify the mechanism of the disappearance of salt-insoluble collagen fibers in the periodontal membrane after abrupt discontinuance of occlusal function and in acute osteolathyrism induced by Aminoacetonitrile (2.5%) in Wistar rats. The salt-insoluble collagen fibers were stained with van Gieson mixture consisting of only picric acid and acid fuchsin on formalin fixed paraffin sections after extraction of salt-soluble collagen in 1M NaCl solution. On the other hand, acid phosphatase was stained by azo-dye method (Barka and Anderson 1963) to demonstrate activity of lysosomal enzyme of fibroblasts in the periodontal membrane after decalcification in Tetrasodium ethylenediaminetetraacetate solution. The following results were obtained: 1) The discontinuance of occlusal function resulted in rapidly progressing disappearance of the salt-insoluble collagen fiber from the alveolar side of the periodontal membrane in molar. Concurrently with the disappearance of the insoluble collagen fiber the acid phosphatase of the fibroblast in the alveolar side of the periodontal membrane increased considerablly in activity. 2) In Aminoacetonitrile induced osteolathyrism the salt-insoluble collagen fiber in the periodontal membrane progressively extensively disappeared from the alveolar bone side. Pathologic osteoid matrix appeared in relatively regular arrangement in the periodontal membrane with reduced insoluble collagen fiber. The acid phosphatase of the fibroblasts did not increase considerablly in activity of the enzyme. 3) These findings suggest that in the discontinuance of occlusal function more active degradation and subsequent intracellular digestion of collagen by fibroblast may be responsible for the disappearance of the insoluble collagen fiber in the periodontal membrane. In acute osteolathyrism the impaired maturation of newly synthesized collaen molecule and not impaired process of extracellular degradation as well as intracellular digestion of collagen by the fibroblast probably result in the disappearance of the insoluble collagen fiber in the periodontal membrane.

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The present histopathological and histochemical study was performed on the periodontal tissues of 100 teeth from autopsy materials and gingivae removed operatively from the 55 patients with marginal periodontitis to investigate a permeability and defense mechanism of the crevicular epithelium in marginal periodontitis. In addition, histochemical reaction was carried out on the lingual and buccal mucosa of rats and mice on which Zinc chloride (4%) had been topically applied to investigate the change in dehydrogenase activity of the epithelium and subepithelial insoluble collagen. The following results were obtained:
1) Subepithelial inflammation of the pocket in marginal periodontitis may consist of subepithelial nonspecific inflammatory reaction (vascular dilatation, slight and moderate exudation of serous fluid and leucocyte) and of adjacent immunological response (diffuse infiltration of plasma cell and lymphocyte). 2) There is rather close correlation between intensity of subepithelial inflammation as well as disappearance of the insoluble collagen fiber and increase in intercellular space of the pocket epithelium as well as amount of bacterial plaque in the pocket. 3) The increase in intercellular space of the crevicular epithelium is attributed to serous exudation and responsible for increase in the permeability of the crevicular epithelium. 4) The crevicular epithelial cells may be able to prevent the dilated intercellular space from invasion of plaque bacteria. 5) The crevicular epithelium had high activity of acid phosphatase even in the epithelium with inflammatory change such as increased intercellular edema and desquamation. 6) These findings suggest that the lysosomal enzyme of the epithelial cell contributes to defense mechamism of the crevicular epithelium by hindering bacterial invasion and reducing a harmfull effects of endotoxin, antigenic substance and bacterial products on the pocket wall.

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Extract solution from commercially available periodontal dressing materials consisting of a eugenol group (Periodontal pack-Pulpdent Co., U. S. A., KIRKLAND periodontal pack-Pulpdent Co., U. S. A., Peridres [Eugenol]-Premier Dental Products Co., U. S. A.) and a eugenolless group (Peridres [Non-Eugenol]-Premier Dental Products Co., U. S. A.) were injected subcutaneously in rabbit's back, and were examined on capillary permeability.
The results obtained were as follows:
1. Extract solution from eugenol group (Periodontal pack, KIRKLAND periodontal pack, Peridres [Eugenol]) and eugenolless group (Peridres [Non-Eugenol]) were not so accelerated capillary permeability of every experimental period (1-day, 3-day, 5-day, 7-day, 10-day and 14-day).
2. Physiological saline solution (Control) have not showed capillary permeability.
3. Extract solution from eugenolless group (Peridres [Non-Eugenol]) have been showed rose color on every experimental period.

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The purpose of this study was to evaluate the effectiveness of new commercially available glass ionomer cement (Fuji ionomer cement, type II) in treatment of cervical hypersensitive dentin and to estimate in vitro fluoride uptake in bovine dentin from the cement.
The results obtained were as follows:
1. The cured cement discs released fluoride contained in the cement powder.
2. Freshly exposed bovine dentin applied with the cement for seven days in water, uptook more fluoride than dentin applied with carboxylate cement or intact dentin.
3. Application of the cement led to considerable reduction in hypersensitivity of dentin to cold, sweet and tactile stimuli over a month. Retention of the cement to the root surface is essential for successful treatment of hypersensitivity, because removal of the cement from root surfaces one month after application, resulted in recurrence of hypersensitivity.
4. The cement supplemented with aluminium fluoride or paraformaldehyde and non-supplemented one were similar both in clinical effectiveness in the treatment of hypersensitive dentin and in fluoride uptake in bovine dentin.

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Removal of dental plaque is the most important measure for successful periodontal treatment. The control of the plaque which accumulates on the distal surfaces of the most posterior teeth is very difficult, because commonly used toothbrush is very hardly reached to the area. Recently we came up a new type of toothbrush which is suited to remove the dental plaque of distal surfaces of the most posterior teeth. Purpost of this study was to know the effect of the newly-designed toothbrush on the removal of the dental plauqe accumulated on the most distal surfaces. Fifteen adults were used for this study. The distal surfaces of the most posterior teeth were disclosed and photographed. Each subject was instructed how to use the new type of toothbrush, and also practiced scrub technique with Perio M^k. Afted 5, 10, 15 and 20 brushing strokes with either of these two methods, photographs were taken. The macrophotographs obtained were projected on the section paper. The extention of plaque and dental surfaces were recorded and evaluated the effectiveness of plaque removal with two different kinds of toothbrush. Results were as follow; (1) There was not significant difference between two type of the toothbrush concerning with the removal of plaque at first five brushing strokes. (2) After 10 strokes, newly designed toothbrush was shown significantly superior to remove the dental plaque. (3) 15 brushing strokes were required to remove completely plaque of the most distal surface. It can be concluded that a newly-designed toothbrush was more effective for plaque removal on the distal surfaces of the most distal molars.

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Free gingival grafts have been used to repair periodontal deformities resulting from gingival recession. The review of the literature has, however, revealed only a few report of successful root coverage by this technique. The cases of successful root coverage by free gingival grafts technique were presented. In this study, 6 areas of localized gingival recession with root exposure were treated. Following surgical treatment (free gingival grafts) the patients mere examined at intervals of 3, 5 and 8 years and creeping attachment was found in all cases. The creeping attachment ranged from 1 to 3.1mm, an average of 2mm. It is concluded that creeping attachment dose occure following free gingival grafts and the root coverage has been observed during 8 years.

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