• Fukushima Minpo


The Fukushima Prefecture Dental Association will spearhead efforts to determine whether children’s teeth contain the radioactive isotope strontium-90 amid worries they were exposed to fallout from the triple core meltdown at the Fukushima No. 1 nuclear plant in March 2011.

The research, part of an Environment Ministry project to examine the health impact of the Fukushima disaster, would be the first large-scale examination to be conducted of children’s teeth. Dental associations nationwide, including in Hokkaido and Kyushu, will cooperate with their Fukushima counterpart in the study.

Similar to calcium, strontium-90 tends to be absorbed by the bones and teeth once it enters the body. It is widely believed to cause bone cancer and leukemia, and cannot be detected by whole body radiation counters.

The teeth of children aged 5 to 15 will be checked if extracted during regular dental visits with their consent or that of their families, and the results will be shown to them.

The research will start by examining the teeth for cesium or other isotopes. Any teeth found with high radiation levels will be further checked for the presence of strontium-90.

For the other teeth, checks for such radioactive isotopes won’t be carried out on individual teeth but in groups of 10.

At the end of last year, the dental association agreed with the two universities to cooperate on the research.

Since extremely accurate readings are necessary to detect small amounts of strontium-90, Tohoku University in Miyagi Prefecture will be in charge of the study because it has precision measuring equipment and know-how.

Ou University in Fukushima will collect and compile the data in the prefecture.

The parties started the study Thursday on a trial basis to prepare for the process of collecting and analyzing the teeth.

They will check the teeth of between 1,000 and 2,000 children over the next fiscal year, which starts in April, and continue the research beyond that time. They will increase the amount of teeth checked annually if so requested.

Fukushima residents are particularly worried about internal radiation exposure because strontium-90 easily accumulates in bones and teeth.

“We’d like to provide a source of relief by disclosing the research data,” said Hitoshi Unno, 52, executive director of the dental association, explaining the significance of the study.

The education ministry released readings for strontium detected in the Fukushima area in September 2011 that said the amount present in soil was less than a hundredth of the cesium present, on average.

“Based on past radiation data, any detected amount would be extremely small. If that is proved by the research, people will feel relief. I want the researchers to take the time to explain the results to the children whose teeth will be examined,” said Noboru Takamura, 45, a professor of Nagasaki University who specializes on the impact of radiation on human health.

The dental association plans to accept applications and inquiries from residents in Fukushima.

This section, appearing every third Monday, features topics and issues covered by the Fukushima Minpo, the largest newspaper in Fukushima Prefecture. The original article was published on Dec. 24.

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