Beauty is only ____1____. 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 ____2____ and our mouthwash. But how does fluoride work its magic? Many figured that fluoride chemically reacts with the main mineral in enamel to form a thick, decay-resistant veneer. But the latest research ____3____ that idea in the teeth.
Scientists in Germany used x-ray photoelectron spectroscopy to get a detailed 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 ____4____ by ordinary chewing.
How fluoride keeps the tooth fairy away is a mystery that researchers are still working to ____5____. In the meantime, we may not know how it works, but we know that it works. So keep brushing.
【視聽版科學(xué)小組榮譽(yù)出品】
skin deep toothpaste kicks worn away unravel
氟化物在牙科領(lǐng)域如何發(fā)揮作用仍是一個(gè)謎 美麗只是外表而已，一口潔白閃亮的牙齒甚至更“膚淺”。這么說是因?yàn)橐豁?xiàng)新研究表明氟化物形成的保護(hù)膜比專家們料想的還有薄。研究結(jié)果發(fā)布在《朗繆爾》（Langmuir）雜志上，是其封面報(bào)道。 美國(guó)消費(fèi)者每年花在消滅蛀牙上的費(fèi)用超過500億美元。當(dāng)我們意識(shí)到氟有助于保護(hù)牙齒，我們就把它放入我們的飲用水、牙膏和漱口水中。但是氟是如何發(fā)揮其魔力的？許多人認(rèn)為氟跟牙釉質(zhì)中的主要礦物質(zhì)發(fā)生化學(xué)反應(yīng)，形成一層厚厚的、抗蛀齲的保護(hù)面。不過這項(xiàng)最新研究顛覆了我們對(duì)牙齒的這種想法。 德國(guó)科學(xué)家利用X射線光電子光譜法繪制出一個(gè)治療過的牙齒表面的詳細(xì)圖像。他們發(fā)現(xiàn)，保護(hù)敷層實(shí)際上只有6納米厚，大概是一張紙的千分之十五的厚度。而這樣薄薄的一層只是普通的咀嚼就會(huì)被磨損殆盡。 氟是如何保護(hù)牙齒讓牙仙女遠(yuǎn)離我們是一個(gè)研究人員仍在努力解開的謎。在此期間，我們不知道它是如何工作的，但我們知道，它的確在發(fā)揮作用。因此，請(qǐng)堅(jiān)持不斷地刷牙吧。