Paper short abstract:

The aim of this presentation is to examine the number of missing teeth in ancient Japanese. Ancient Japanese people had many remaining teeth. This result was unexpected. The notion that “ancient peoples lost more teeth more quickly” does not seem to apply to ancient skeletal remains from Japan.

Paper long abstract:

Excavated human skeletal remains consists of Kofun (4th-7th), Kamakura (1185-1333 AD), Muromachi (1336-1573 AD) and Edo (1603-1868 AD) periods have shown that Japanese people maintained a surprisingly high number of remaining teeth even in pre-modern times. The materials were 145 excavated human skeletons whose maxillas and mandibles were both examinable. The individuals were divided into groups, such as the early middle age and the late middle age. The status of missing teeth was compared between groups. The rates of tooth loss were examined in the maxillas and the mandibles. In people of every period, many teeth remained in good condition until early to late middle age. However, people of all periods clearly showed increased tooth loss with age. Dental caries and periodontal disease were two major diseases in pre-modern Japan. However, the average life span remained almost unchanged from the Kofun period approximately more than 1500 years ago until the pre-modern times in the Edo period. This lack of improvement was speculated to be due to insufficient intake of nutrition from food and deaths from infection. The number remaining of teeth was low in the elderly individuals, and a large number of lost teeth were likely directly associated with death in periods before modern times. In modern oral medicine, the focus has been on how to reduce eating impairments. The reason is that body functions rapidly decline when nutrient intake is insufficient, which can directly lead to death in elderly individuals.