Abstract
The purpose of this paper is to survey the influence of the nursery school period on dental caries prevalence in the deciduous teeth of nursery school children. The children studied here had finished nursery sdhool in March,1977 and 1978; they numbered 228 (128 boys,100 girls).
The children were cla s s ified into 4 groups according to the number of years spent in nursery school. The five-year group had attended nursery school continuously for five years from about the age of two. The four-year group had attended regularly for four years from about the age of three, the three-year group for three years from about the age of four, the two-year group for two years from about the age of five. The difference in the prevalence of dental caries in these groups was examined. The results obtained are as follows.
1. The prevalence of dental caries showed similar tendencies in the four groups. However, from an early period, the rate of def teeth in the five-year grou p was shown to be 7`10% lower than that in the other three groups.
2. The rate of def-teeth and def-surface teeth in the four-year group, which had been attending nursery school from about the age of three, showed higher values than the five-year group. Those values were similer to the values in the two and three-ye ar groups.
3. The decrease in the rate of def-teeth for the five-year group was more remarkable in the maxillary anterior teeth.
4. In the maxillary molars, the rate of def-surface teeth showed tendencies similar to that in the maxillary anterior teeth.
Although children spend o n l y about eight hours in nursery school, during this period at least there is limitation on the amount and number of meals or snac ks. The slow-down in the occurrence of caries in the five-year group can be attr ibuted to the influence of a correct, controlled diet from before the eruption of deciduous molars, if only for the nursery school period.
