Beavers' Decay-Resistant Tooth Enamel May Save Humans' Teeth

Beavers may have shown scientists a way to improve human tooth enamel. It turns out that they have protection against tooth decay built into the very chemical structure of their teeth: iron.

Beavers don't have access to fluoridated water like humans, but they show a remarkable lack of tooth decay despite this. Not only that, but their enamel is harder and more resistant to acid than regular enamel, including that treated with fluoride.

Enamel is a complex structure, which makes studying it particularly challenging. It's composed of layers of well-ordered hydroxylapatite "nanowires." Recently, though, researchers have found the material surrounding these nanowires were small amounts of amorphous minerals rich in iron and magnesium.

"We have made a really big step forward in understanding the composition and structure of enamel-the tooth's protective outer layer-at the smallest length scales," said Derk Joester, one of the researchers, in a news release. "The unstructured material which makes up only a small fraction of enamel, likely plays a role in tooth decay. We found it is the minority ions-the ones that provide diversity-that really make the difference in protection. In regular enamel, it's magnesium , and in the pigmented enamel of beaver and other rodents, it's iron."

It turns out that a beaver's teeth aren't structurally different from our own teeth. Instead, they're chemically different. By understanding these teeth, scientists may be able to improve current treatment with fluorite. Which a staggering 60 to 90 percent of children who have had cavities and nearly 100 percent of adults worldwide who have had them, it's crucial to develop new methods to prevent these from occurring.

The findings are published in the journal Science.

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