Abstract
On the basis of the dental health examination of 751 infants (398 boys and 353 girls) at the age of 3 years and one month +2 weeks and the questionnaires given to their mothers, factors contributing to dental caries were sought. The oral examinations of the infants included the incidence of dental caries, the pH value of Cariostat, height and weight. As for their mothers, the questionnaires were done in regard to their nursing methods, dietary habits, tooth brushing habits and other dental knowledge which might be familiar to mothers.
Discriminant analysis was carried out by subjecting those items investigated to the first class of Hayashi's quantifying theory, in which the ratio of the number of decayed teeth divided by the number of erupted teeth for each infant was chosen as an external criterion.
As a result, the factors contributing most to the dental caries at the age of 3 were found to be the pH value of Cariostat, the nursing method, the nursing environment, and the developmental factor. It was suggested that these factors might be the most important items, when oral hygiene instruction for the child is given.
