Disaster Preparedness / Oral Care Essential Even During Disaster Evacuation

By Ayaka Kaji / Yomiuri Shimbun Staff Writer

19:57 JST, June 23, 2025

People tend to be reluctant to brush their teeth when it is difficult to obtain a sufficient amount of water in the event of a disaster.

In a prolonged disaster situation, germs could increase inside the mouth if oral care is not performed regularly, possibly resulting in life-threatening diseases.

It is good to know some key points of oral care that can be done without much water.

Risk of aspiration pneumonia

“Although people believe they will not die even if they do not brush their teeth, germs inside the mouth could cause an illness that may be life-threatening to an elderly person,” said Koichi Nakakuki, a lecturer at the graduate school of Tohoku University who has conducted relief activities in disaster-hit areas as a dentist.

If people fail to brush their teeth or wash artificial teeth because tap water is not available or there is some other inconvenience, germs reproduce and increase inside the mouth.

Failing to perform such oral care raises the risk of developing aspiration pneumonia, which is caused by germs in the mouth entering the lungs, and blood poisoning, which is caused by germs getting into the body through wounds in the mouth.

Such risks that arise during a disaster have gained attention as studies on the relationship between aspiration pneumonia and oral care have progressed since the latter half of the 1990s following the 1995 Great Hanshin Earthquake.

Nakakuki went to areas devastated by the Noto Peninsula Earthquake in January last year and noticed that there were few places with private spaces where evacuees could brush their teeth without worrying about other people watching.

“In evacuation shelters in school gyms and other public facilities, in many cases, there were no restrooms with separate spaces,” Nakakuki said. “I want people not to forget about keeping the inside of their mouth clean even in such situations.”

Promoting secretion of saliva

Keisuke Nomura, a standing director of the Japan Dental Association in charge of disaster relief, emphasized the importance of oral care before going to bed and after waking up in the morning.

People should know that the amount of saliva decreases during sleep and the number of germs inside the mouth increases.

If water is available only from a small plastic bottle, it is recommended to get a toothbrush wet with a little bit of water and brush one’s teeth without using toothpaste.

The key point is rinsing the mouth properly.

“Rather than rinsing the mouth once with a lot of water, doing so twice with small amounts of water can effectively remove stains in the mouth,” Nomura said.

Stains on a toothbrush can be removed with wet wipes. If enough water is available, using toothpaste is OK. After using a toothbrush, it should be dried sufficiently.

If a toothbrush is not available, rinsing the mouth with only water or tea can be effective, Nomura said. Having mouthwash or toothpaste sheets prepared in advance is recommended.

People with artificial teeth need to clean them properly. If people forget to bring agents to wash artificial teeth when they evacuate, scrubbing artificial teeth with a neutral detergent like dish soap is OK.

“Although some people may conceal the fact that they have artificial teeth, I hope they will wash them at least once a day while making efforts such as concealing their mouth with a mask,” Nomura said.

In the event of a disaster, saliva flows less because of stress.

Because saliva has the function of keeping the inside of the mouth clean, it is recommended to promote the secretion of saliva by massaging the mouth or moving it.

“Simply chatting with others and laughing move the muscles of the mouth, which makes saliva flow more,” Nomura said. “I want people to be conscious about moving their mouth.”