The purpose of this study was to find out the actual condition of the imature permanent teeth, the care of imature permanent teeth and the establishment of oral health care during childhood. The subjects,4,080 children (2,015 boys and 2,065 girls) ranging from 5 to 16 years of age, were examined transversally.<BR>This report is concerned with the results of an investigation into the state of caries prevalence, and that of restoractive treatment, in particular, based on age and degree of eruption.<BR>The findings were as follows.<BR>1) The prevalence rate of dental caries among the boys and girls was as follows, respectively: 19%and 20% at the age of 6; 80% and 80% at the age of 12; 89% and 93% at the age of 16. The mean number of decayed, missing or filled (DMF) teeth per child among the boys and girls was as follows, respectively: 0.4 and 0.5 at the age of 6; 3.8 and 4.1 at the age of 12; 6.6 and 8.6 at the age of 16. The rate of DMF teeth based on age was the highest,50-60%, in first molars at the age of 12, which was followed by 20-30% in second molars. The first and second molars in particular resulted in a high prevalence rate of caries,30%, even in the middle of eruption, The second molars showed a higher prevalence rate than the first molars regardless of the degree of eruption.<BR>2) The mean number of treated teeth per child among the boys and girls was as follows, respectively: 0.2 and 0.2 at the age of 6; 2.6 and 2.9 at the age of 12; 4.6 and 6.8 at the age of 16. Filling with resin was rather frequently observed in the anterior teeth and premolars. The molars were treated more frequently by filling with resin or by repair with inlays, and the latter in particular showed an increasing tendency with age. The rate of treatment by preventive condensation on teeth after the completion of eruption was 20% for premolars,30-40% first molars and 20-30% for second molars.