Emergence of permanent teeth and onset of dental stages in Japanese children.

The purpose of the present cross-sectional study was to provide mean times of emergence of permanent teeth and onset of dental stages in Japanese children. A total of 1819 schoolchildren aged 6-15 yr were recorded. The results demonstrated specific sequences of emergence in the two arches and earlier emergence times in girls than in boys, both findings in keeping with investigations on other ethnic groups. Secular trend in tooth emergence was studied by comparing the results with data on Japanese children in 1934. The comparison revealed earlier mean times of emergence in general in contemporary Japanese.