This is Scientific American 60 Second Science.

I'm Christopher in D'Artata.

Got a minute?

Ah yes, the old fluoride rinse at the dentist.

Not pleasant, but hey, good for your teeth, right? Well, now

material scientists have been able to figure out why, by mapping the nanostructure of tooth

enamel. If you zoom way in, tooth enamel looks almost like the weave of a basket.

Where each thread is made from thousands of nanowires.

Derek Houston of Northwestern University.

In between those crystalline nanowires,

Euster and his colleagues discovered a sort of amorphous glue.

And that's where the fluoride hangs out, helping to stave off an acid attack of the enamel.

In other words, a cavity.

But the researchers found something that works even better than fluoride, iron.

And they found it in beaver teeth. even better than fluoride, iron.

And they found it in beaver teeth.

So beavers don't get curious.

Chewing through wood is a very good way

to clean your teeth. But another reason they say is the iron-enrich

glue in beaver enamel, which was even more acid-resistant than fluoride-treated

enamel. The findings are in the journal Science.

Of course, iron-rich enamel comes with an unfortunate side effect,

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