Study: Japanese had gum disease in 18th century

A group of researchers says it has found that people in Japan in the 18th to mid-19th century had periodontitis, a gum disease induced by bacterial infections that leads to bone loss around the teeth.

The group, which includes researchers at Tokyo Medical and Dental University, published the results of its study in a Swiss journal on molecular biology.

The researchers analyzed bone samples excavated from a site in Tokyo's Fukagawa area from the 18th to mid-19th century, which corresponds to the latter half of Japan's Edo period.

It says partial bone loss was confirmed in five of 12 samples, showing they were affected by periodontitis.

The group also conducted genomic analysis of dental calculus. It says 24 types of bacteria were detected in the samples from the Edo period, and 17 species were common to samples from modern times. But none of the periodontitis bacteria in modern humans were detected in the Edo samples.

The group says the results suggest differences in the bacterial composition of the oral cavity, and the possibility that different pathogens were responsible for periodontitis in the Edo period.

Assistant Professor Shiba Takahiko of Tokyo Medical and Dental University says he hopes to closely study how the bacteria changed over time, and find pathogens that can be a target of fundamental treatment, so that a new remedy can be found.

He says he plans to further study the dental calculus of samples from earlier eras.