出国留学首选一诺留学

　　听力文本

　　Ah yes.The ol' fluoride rinse at the dentist.Not pleasant.

　　But hey, good for your teeth, right?

　　Well now materials 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."

　　Derk Joester, of Northwestern University.

　　And in between those crystalline nanowires,Joester 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.

　　"Beavers don't get caries.

　　Chewing through wood is a very good way to clean your teeth."

　　But another reason, they say, is the iron-enriched 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: reddish-brown teeth.

　　But Joester says future human dental treatments that employ iron might find a way around that.

　　"We have the entire periodic table to play with minus a few things that are not too healthy.

　　So I'm sure we can come up with a way to do what the beaver does but do it better and do it in a way that still maintains a nice smile."

　　参考译文

　　没错，这是牙医洗牙用的含氟漱口水。确实够闹心的。

　　但毕竟对你的牙齿有益不是吗?

　　现在材料科学家们通过绘制牙釉质的纳米结构已经知晓其中的原因。

　　如果放大牙釉质，它与篮子的纹理非常相近。

　　“每条线都由成千上万的纳米线条组成。”

　　西而在这些晶状纳米线中，乔斯特尔和同事们发现了一种非固定形状的胶质。

　　而氟化物就在这里聚集，帮忙延缓阻挡牙釉质的酸蚀—换句话说抑制蛀牙。

　　但研究人员发现了一样比氟化物效果更好的物质：那就是铁。