CROSS-SECTIONAL COMPARISONS OF CARIES TIME TRENDS IN NURSERY-SCHOOL CHILDREN IN SENDAI, JAPAN

The aim of this study was to clarify the trends in caries experience i n the primary dentition of nursery school children in Sendai, Japan, o ver a period of 20 yr An annual clinical dental examination of childre n aged 2-5 yr at 13 nursery schools in Sendai City was carried out in 1972, 1977, 1982, 1987 and 1992. Data obtained from all five surveys w ere compared in each age group respectively. The percentages of 2-, 3- and 4-yr-olds free from caries increased remarkably until 1977, while that in 5-yr-olds started increasing several years later. After such increments, percentages in all age groups except 3-yr-olds remained al most al the same level with slight fluctuations. The mean deft and def s values per child in 2-, 3- and 4-yr-olds decreased remarkably until 1977, but then remained almost at the same level thereafter. That in 5 -yr-olds continued decreasing slightly during the 20-yr period. The ma rked reduction of caries experience in nursery school children shown d uring the 1970's did not continue through the 1980's or the beginning of the 1990's.