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This is Scientific American's 60-Second Science. I'm Karen Hopkin. This will just take a minute.
Beauty is only skin deep. And the beauty of shiny white teeth is even less deep. Because a new study shows that fluoride forms a thinner protective shield than experts thought it did. The results appear in the surface science journal Langmuir.
American consumers spend more than $50 billion a year fighting cavities. When we realized that fluoride could help, we put it in our drinking water, our toothpaste and our mouthwash. But how does fluoride work its magic? Many figured that fluoride chemically reacts with the main mineral in enamel1 to form a thick, decay-resistant veneer2. But the latest research kicks that idea in the teeth.
Scientists in Germany used x-ray photoelectron spectroscopy to get a detailed3 image of the surface of a treated tooth. And they found that the protective covering is actually only 6 nanometers thick. That's about a fifteen-thousandth as thick as a sheet of paper. And a layer that skimpy would likely be worn away by ordinary chewing.
How fluoride keeps the tooth fairy away is a mystery that researchers are still working to unravel4. In the meantime, we may not know how it works, but we know that it works. So keep brushing.
Thanks for the minute. For Scientific American's 60-Second Science, I'm Karen Hopkin.
1 enamel | |
n.珐琅,搪瓷,瓷釉;(牙齿的)珐琅质 | |
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2 veneer | |
n.(墙上的)饰面,虚饰 | |
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3 detailed | |
adj.详细的,详尽的,极注意细节的,完全的 | |
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4 unravel | |
v.弄清楚(秘密);拆开,解开,松开 | |
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