1959 年 9 巻 2 号 p. 136-149
Sugar consumption of the individual Japanese during the war period between 1943 and 1945 was extremely reduced, and during the worst year, it was less than 1kg. a year.
The author carried on a statistical study, using a method contrived by Prof. Mitsuharu Takeuchi with the opinion that, in order to take a statistics of the rate of caries incidence, it should be compiled from the new carious incidence in one single kind of tooth during a year. For the material, the records of the dental examinations on 7, 894 primary school children in Tokyo, who were born between 1929 and 1951, were employed. The results were as follows:
1. The interrelative ratio between the amount of total sugar consumption of a child during the maturation period of the tooth (0-5 years old) and the rate of new caries incidence in the first moler during 6-11 years of age, indicates that there is an extremely little co-relation between them.
2. On the other hand, the interrelative ratios of the new caries incidence in the first moler to sugar consumption are: the year of the new caries incidence, the year before and the year before last are respectively 0.8, 0.7 and 0.6. Therefore, caries incidence is statistically clear to have a close relation with sugar consumption of the same year or the previous year.
3. Moreover, it was presumed that on the semilog graph, the rate of new caries incidence during a yeaa and the sugar consumption during the same year will show a straight line, and when the element other than sugar which may cause incidental caries was subduced, they will make a slow curve on it.
4. The first molers of the upper and lower jaws are naturally have different tendencies of caries infection (It is different in each tooth.); whereas effect of sugar appears to be equally strong for them.