ON A FEW INFLUENCES OF THE DENTAL CARIES IN THE ELEMENTARY SCHOOL PUPIL BY Teruko KASAKURA, Naonobu IWAI, Sachio TAKADA Department of Hygiene, Nippon Dental College (Director: Prof. T. Niwa) The relationship between the dental caries and the physical constitution together with the incidence of absence to school, which might be connected with learning, was investigated by making use of individual records of both physical and dental states at the time of the periodical health examination in 1963 on 259 pupils, the second- to the 6th-year graded, of a certain elementary school at a central part of Tokyo City. As for the classification of caries proceeding grades, deciduous teeth and permanent teeth were separately divided into either the treatment teeth or the carious teeth. In particular, carious teeth among permanent teeth were subdivided into the dental caries of the first grade (C1), of the second grade (C2), of the third grade (C3) and of the fourth grade (C4). Concerning to each grade, the average number of carious teeth per person was calculated and checked in relation to the physical constitution such as the height, the weight and the girth of the chest and to the incidence of absence to school, obtaining the following results. 1. In the height, as compared with those who showed higher values than the national average value, those who showed lower values had more carious teeth. In deciduous teeth, the number of carious teeth was larger equally in pupils of all the year grades, while in permanent teeth the number of carious teeth of C2 and C3 was larger in them except for the 5th year grade. 2. In the weight, those pupils who showed lower values than the national value of average, as compared with those who showed higher values, had more carious teeth in deciduous teeth throughout the year grades. Meanwhile, in case of their permanent teeth, the number of treatment teeth were smaller in the 2nd, 4th and 6th year grades. However, the 6th-year graded pupils showed a little larger number of C2, C3 and C4 carious teeth. 3. In the girth of the chest, those pupils who showed lower values than the national average value, when they were compared with those who showed higher values, had generally more carious teeth in deciduous teeth throughout the year grades. In permanent teeth they exhibited a small number of treatment teeth except for pupils of the 3rd year grade. At the same time, it may be said that C1 was rare except for the 5th-year graded pupils, while C2, C3 and C4 occurred in general frequently. 4. As described above, it was observed that carious teeth appeared rather often in case of the poor physical constitution at the time of the examination, that means, in pupils showing a poor bodily development, suggesting the importance in the protection of deciduous teeth during the elementary school period. 5. During one year before the physical examination, those pupils who were never absent to school showed, in comparison with those who made as many as more than 10 times of absence, more numerous carious teeth of deciduous teeth in the 2nd, 3rd and 4th year grades and C1, C2 and C3 of permanent teeth in the 5th and 6th year grades. Therefore, it is assumed that the absence to school may be connected with the caries of the deciduous tooth in pupils of the low and middle year grades and of the permanent tooth in those of the high year grade. 6. Similarly, if the R.I.D. Index (1961) of pupils making no absence was compared with that of pupils showing many times of absence, the former exhibited lower values throughout the year grades. Consequently, those who showed high caries proceeding grades of both deciduous and permanent teeth, showed also frequent absence to school.