For researching the anti-carious action of stannous fluoride, it seems to be one of the important problems to detect histochemically tin in dental enamel. However, the present knowledge on the location of tin in tissue is very poor, particularly in dental enamel; it has never been observed.
For the purpose to establish a stable and applicable histochemical method for tin in dental enamel, an attempt was made to apply the Okamoto's histochemical method with phenyl trioxyfluoron-o-carbonic acid (gallein), which had been originally devised for soft tissues.
Freshly extracted teeth were employed in this experiment. A half dental crown was treated with stannous fluoride, while the other falf was remained untreated as the control, and the whole crown was stained with gallein solution. After being stained, the ground sections were made and observe to estimate the staining states of tin in enamel under the microscope.
Gallein-tin reaction found on sections appeared red as expected, but the enamel surface was partially decalcified with the strong acidity of the staining solution. The grade of decalcification seemed to be parallel with the staining capacity which was increased by the elevation of temperature or the elongation of staining time. Moreover, in these attacked sites, the color changed to yellowish-brown like a caries lesion owing to the impregnation by gallein.
Owing to this drawback, it was difficult to differentiate clearly the color between gallein and gallein-tin; hence the distinct localization of tin in or on the intact enamel surface was not detected.
From these experiences, the authors were forced to devise a new staining method for tin applicable to dental enamel and other hard tissues.
The details of the new method will be reported in the next paper.

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This paper was presented the data of dental health of the group of children four to five years living for the major portion of their lives in orphanages in Osaka, Japan.
Detailed surveys were made in relation to dental caries, the diet and the physical health of the children.
For purposes of comparison, studies of groups of children of similar age to the orphanage were performed. The orphanage groups consisted of fourty six children were available for the dental and dietary examination. It was found that the mean d. f. teeth rate for the children ranged from 2.0-13.5. A comparable study of children revealed a mean d. f. teeth rate of 45.5.
An analysis of diet of the orphan children shows that the main essentials were adequate. The total caloric intake of the children was quite similar to that of the control. However, much calorie was taken from an eating between meals, mainly a refined carbohydrate, in the comparable group. The physical health of the children was essentialy the same to that of the control.

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Transition of decay, missing and filling of the first molars was investigated for ten years using 119 female laborors who were born during 1932 and 1938 and had been working in a factory more than 10 years since they entered it at 15 years of age, with results as follows:
1. The rate of DMF teeth in the seven cohorts showed a remarkable rise, that is, the average value increased from 45.4% to 73.3%. The rate of D-teeth alone showed a descend from 31.7% to 17.4% while those of F-teeth and M-teeth showed remarkable ascend, from 7.4% to 40.1% and 6.3% to 15.8%, respectively.
2. The rates of individuals having caries experience in their first molars were as high as over 80% in all Cohorts who were born during 1932 to 1936, while those in 1937 birth Cohort and 1938 birth Cohort were relatively low. As a general tendency in all cohorts, rates of DMF teeth and individuals having DMF first molars show an abrupt rise at 16-18 years of age, gradually ascending thereafter.
3. The rate of F-teeth and that of individuals having a completely treated F-teeth in each cohort show irregular curves but they always tend up-ward throughout the ten years.
4. Each cohort showed a gradual increase of missing teeth, the average value changing from 6.3% at 15 years of age to 15.8% ten years later. The rate of individuals having missing molars rose from 13.4% to 38.6%.

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One of the causative agents the periodontal diseases could be induced sometimes by the changes of circumstances in oral cavity, and it might be vice versa, so many investigators have already informed on this sort of study. While biochemical studies relating to this matter are being active in these days, subsequently, it is reported that the pH of saliva or salivary ammonium amount are closely related to the periodontal diseases.
On the dental caries which is another one of the 2 largest diseases in oral cavity, the studies on the dental caries activity have been briskly undertaken together with the investigations for the disintegrative mechanisms and the resistant factors, besides, it could be found few works on the periodontal disease activity.
The author just then interested in this problem on the“Periodontal disease activity”, of which term had been proposed by Mashimo et al (1962), and the salivas of periodontal diseases' patients has been examined bacteriologically and biochemically. Consequently, it was observed that the symptomatic degree of periodontal disease closely related to the activity of proteolytic enzyms come from the oral microorganisms indigenous to saliva, moreover, this fact was verified by means of the statistical observation.
The results could be summed up as follows:
1. The testing procedures for the proteolytic activity of human contaminated saliva was devised due to employing the hide powder for substrate and measuring the results by ninhydrin test. The experimental salivas were collected with particular terms at just before lunch, of which procedures were not followed in the former steps.
2. It could be recognized that there were distinctly discrepancies between the salivas of normal controls and of the periodontal diseases, and that the degree of proteolytic acitivity was directly proportional to the symptomatic status of periodontal disease.
3. According to the clinical experiments employed this technique, the salivary proteolytic activities were classified to 3 different types as follows:
A) After treatment, the activity increased for 4 to 5 days, gradually decreased after that, and it became negative by the 30th day.
B) After treatment, it rapidly decreased for 3 to 4 days, increased again and was restored up to the former level.
C) This type showed irregular curve and rather increase after operation.
All cases in A-group checked no abnormal components in the urine, B and C-groups showed various abnormal components in the urine.
4. It was observed the relationship of this activity with the salivary buffer capacity, namely, the saliva of the high proteolytic activity demonstrated large buffer capacity, generally the pyorrheas' saliva showed the large capacity.
Judging from these results, it could be trusted that ex amining the proteolytic activity in saliva is useful as one of the periodontal disease activity tests. Furthermore, it might be imagined that this procedure is helpful for learning the progress and prognosis after operation for the periodontal diseases, which related with the systemic conditions, especially, with another organic anomalism.

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