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Duncan Geere

Duncan Geere

News Editor,

Technology used in the cold storage of sushi has been extended to the cryo-preservation of teeth, with researchers at Japan's Hiroshima University claiming that they could be kept frozen for as long as 40 years.

Cryonics is difficult. Freezing body organs quickly means saturating them with poisonous levels of antifreeze, but freezing them slowly means that their cellular structure is ripped apart by the formation of ice crystals.

Sushi is similarly tricky to freeze -- ice crystals destroy the texture of the rice in the same way. So a method of supercooling the bite-size Japanese food was developed. It relies on magnets, which vibrate the water using magnetic fields and allow them to reach -10 celsius without freezing. Once the magnetic field is turned off, the water instantly freezes, without any time for ice growth. Once thawed, the sushi is perfectly edible. Here's a video demonstration with a bottle of water:

The process is in use at The Teeth Bank in Hiroshima, which is the world's first commercial tooth bank. You can store teeth that you have to have extracted for later use -- for example, a wisdom tooth could be removed, then re-implanted years in the future. But you need to keep it safe in the meantime, and preserving teeth requires keeping their ligaments alive. Slow-freezing a tooth destroys those ligaments, so the Teeth Bank uses the same super-cooling method employed by sushi freezers. It's thought they could be kept safely for up to 40 years.

Of course, teeth are just the first step. What's really interesting is the translation of the magnetic supercooling method to use for organs. Progress is being made, but it doesn't look like the company's quite there just yet -- due primarily to the very high safety barriers around experimenting with human organs (animal trials are underway) and the long testing process; organs must be frozen for some time before they can be defrosted and examined for damage.

In the meantime, if you need any teeth frozen for 40 years, you know where to go.

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