Historical Change of Dental Carious Lesions from Prehistoric to Modern Times in Japan

The aim of this study was to document the historical change of dental caries lesions in the Japanese people. The majority of carious lesions in historical populations from the Jomon to Edo period were located in the neck and/or root of the approximal surface (NRAS). Caries on the occlusal surface (OS) were rare in both the Jomon and Kofun populations, but there was a relatively high rate (17.6-24.7%) in the Kamakura, Muromachi and Edo periods. People in both the Jomon and Kofun periods had severe dental attrition; therefore, due to the disappearance of fissures and pits, caries on the OS did not arise. However, after the Kamakura period, the attrition was moderate, so occlusal caries increased. Caries on the lingual surface (LS) and the neck and/or root of the lingual surface (NRLS) were rare in all Japanese periods. The incidence may be associated with a self-cleaning action with the tongue and the saliva. In the modern population, the most frequent lesion is on the approximal surface (AS), followed by the NRAS and the OS. The rate of coronal caries is higher than that of root caries only in modern times. It seems reasonable to suppose that the former is a modern type of caries, and the latter is ancient. Furthermore, it can be said that from the Jomon to Kofun or from the Kofun to Kamakura periods, and from the Edo to modern times, are turning points for different types of caries in the history of Japan. The type of carious lesion is a good indicator of oral health condition, including dietary habits, subsistence and lifestyle in each period.