After the 2011 Tohoku earthquake and tsunami, Sunstar created an award-winning TV commercial to communicate this message (available in Japanese).
To further disseminate this, we have just launched an educational oral care website along with a basic disaster kit checklist.
http://jp.sunstar.com/bousai/en/
The site is available in Japanese, English, Chinese, and Korean.
It is our sincere hope that this information will make a difference in case of a disaster.