In pruvious papers, Miura (J.J. s. 14, 103, '65) Miura and Fujimaki (J.J. s. s. 15, 257, '66) reported that genus neisseria isolated from oral materials has cytochrome respiratory system.
In the present study of same bacterial metabolism, I found to have another metabolic pathway differ from cytochrome respiratory system when glucose was added to reaction mixtures as snbstrate in routine biochemical method, and obtained the following results:
1. the resting cell of genus neisseria may be well utilized glucose.
2. the added glucose utilization by the resting cell manometrically was not always coinsides with O₂ consumption
3. when the suitable concentration of NaN₃ and DNP was added to reaction mixuture, after some time, O₂ consumption increased rapidly.
From these results, it may be seem to have the oxidative assimilation of glucose in oral bacteria.

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The preventive effects of stannous fluoride-dentifrice cn dental caries experience were tested on first grade children in 15 primary schools. They were divided into three groups. The children in group A were given fluoride-free dentifrice (dentifrice A), in group B, they were given dentifrice containing 500 ppm fluorine (dentifrice B) and in group C, they were given 1, 000 ppm fluorine dentifrice (dentifrice C). The dentifrice B and C contained stannous fluoride, calcium pyrophosphate and stannous pyrophosphate, which were prepared specially for the experiment and not sold on the market. Each children was given the respective kind of dentifrice and an uniform type toothbrush, and were taught to brush the teeth at home twice a day, morning and evening.
Afer two years of unsupervised use of dentifrice C (1, 000 ppm F), it was shown about 13 per cent reduction in new DMF teeth as compared with that of the control group. The teeth that were erupting during the experimental period showed about 30 per cent reduction compared with the control group, but the teeth already erupted at the start of experiment showed less effectiveness than the erupting teeth.
There were found no evidence of reduction in dental caries in group B using 500 ppm F dentifrice.

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1) 76 strains belonging to 17 species or bacterial groups were tested in respect of pigmentation of the small piece of the tooth placed in 1% glucose broth. It was found that the organisms which produced acid from glucose could stain deeper depending on their pH level of the broth reached during 20 days incubation at 37°C.
2) One of the determinate factors for the pigmentation was found in the meat extract which consist of the glucose broth and it was removed after absorption by activated charcoal. The second determinant was considered to be releasing of reactive groups of the tooth which is inactive under physiological circumstances.
3) The activation of such reactive groups might be brought by either lowering pH of the medium or addition of chelating agent, used Na₂-EDTA in this study, in alkaline reaction. Thus it might be the removal of calcium blocking the reactive groups of some organic moiety of the tooth.
4) In addition to the meat extract, browning substances were also found in yeast extract, soy bean sauce, autoclaved pepton solution containing humin, caramelized glucose solution and neutralized pyruvic acid solution. Exogenous or dietary pigments may also play some role in the browning of the carious process.
5) The fact that pigmentation occured in the caramelized glucose solution in alkaline reaction is most interesting in this study. Formation of Ca-saccarate may cause releasing the reactive groups of the tooth.

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It is well known that dental caries is the disease of the highest morbidity among all kind of diseases also in Japan. As an epidemiologic approach to the etiology of dental caries, which is remaining unsolved, correlation coefficients are calculated between the dental caries prevalence rate in school children and some biological and social factors, especially the consumption of selected foods, by 46 prefectures. The results follow:
1. Positive correlations between the dental caries prevalence rates in elementary school children and junior secondary school pupils in 1957 and that in 1961, are significant at the 0.1% level both in boys and girls. Positive correlations between dental caries prevalence rates in 1936/1937 and that in 1957/1961 are significant at the 1% level both in boys and girls.
2. Among correlations between the dental caries prevalence rate and blood type distribution, negative correlation with the proportion of blood type A is significant at the 0.1% level in the elementary school children.
3. Positive correlation between the prevalence rate in the junior secondary school pupils and the age specific death rate for cancer of stomach is significant at the 5% level.
4. Positive correlations for the prevalence rate in elementary school children are significant with the consumption of cakes and candies at the 0.1% level, with processed food and bread at the 1% level, with fruits, milk and dried and salted fish at the 5% level. Positive correlations for the prevalence rate in junior secondary school pupils are significant with the consumption of cakes and candies and processed food at the 0.1% level, with milk and dried and salted fish at the 1% level, with bread at the 5% level.

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The prevalence rate of dental caries of 5055 boys and girls of 7 and 11 year-age classes of the elementary schools and 15 year-age classes of the junior secondary schools was compared between the inland farm and the coastal fishing areas in the north-eastern part of Japan main island.
The dental caries findings were expressed by the D. M. F. and/or d. e. f. indices. The results follow:
1) Caries prevalence of deciduous teeth expressed by the percentage of d. e. f, was significantly higher in the coastal area at 11 year-age class of girls, and that of permanent teeth expressed by the percentage of D. M. F. was also significantly higher in the coastal fishing area at 15 year-age class of boys. The probability products show the significantly higher prevalence for the girls through the age classes.
2) On the other hand. the d. e. f. teeth rate was significantly higher in the coastal area at 7 and 11 year-age boy and 7 year-age girl classes. Also the D. M. F. teeth rate was significantly higher in the coastal fishing area at 15 year-age boy and 11-year girl classes. The probability products show the higher prevalence in the coastal area with the significance level of P<0.05-0.001 for both d. e. f. and D. M. F. teeth rates.

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In response to the increasing social need for the mass treatment of periodontal diseases, 185 workers, composing a plant of the Tokyo Shibaura Electric Co., Ltd., have been picked up the study. Survey of thier periodontal states were made on the following five items; number of deposits on the visible internal and external tooth surfaces, depth of the gingival pocket at the medial and distal side of the gingival papilla, blood content in a gargled water regarded as gingival bleeding, redness of papillomarginal gingiva, and activity of the calculus formation (ACF). Depend on the pathological, statistic and/or strategic view point in the operation of the public health program. indexing of the results on the items surveyed and correlation between either two of them for the simplification of the screening items were performed and reached the following test program to be operated for this disease.
The 1st screening will be carried by disclosing solution made of neutral red and persons possessing 7 or more than 7 sites of deposit will be indicated to receive thorough scaling which is necessary precaution for the 2nd screening of the gingival pocket. People who have 6 or lesser than 6 deposits and none of the pocket deeper than 3 mm will be screened out as they belong to the “intact group”. A “pockety group” will be receive general anti-inflammative treatment and some minor surgery for the elimination of the pocket by general practioners in dentistry and cases diagnosed need for more complicate treatment will be passed for the special treatment by periodontologists. The“recall group”, consisting of the people who have been eliminated the pocket and/or the deposit will be first fixed their proper scaling interval based on the activity test on the calculus formation. A very active depositor who needs a scaling for every 3 months will be recommended to use the calculus splint for the prevention. They will receive training of the proper tooth brushing for every individual under the aid of the disclosing depositous. Finding of gingival hemorrhage in this group will be regarded as either commensment or return of the pocket. At the Department of Preventive Dentistry, Tokyo Medical and Dental University, School of Dentistry, the scaling interval have been determined by The activity of calculus formationi; (ACF: Ca content of the deposit on the lower incisors during one month) as the following table.
A thin discus with the diameter of 3 mm fixed on the point of a gingival explore were deviced for the screening of the pocket which have been meassured at the medial proximal of every tooth. Phenolphthalin was applied for the detection of slightest blood in a gargled water.
It was estimated that a dental team composed by one general dentist, one dental hygienist, and one auxialiary may operate the above program for a population group of approximately 4000 workers at 1st year and 6000 at the successive year.

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