摘要：It is well known that the Japanese of to-day has one of the highest frequency of dental caries as other civilized peoples in the world. On the contrary, it has been reported that the caries were much less frequent among the prehistoric and protohistoric Japanese than among the recent Japanese. The aim of this study is to know the process of increase of caries through the time sequence from the ancient up to the present, by examining caries in the skeletal material of various historic periods between protohistoric and recent periods, and comparing the frequencies of them with each other.
