Fluoride helps fight cavities. That's why it's in our drinking water and toothpaste. But how this mineral works its dental magic is still somewhat mysterious. Now, researchers offer an incisive solution. They find that fluoride treatment can loosen bacteria's grip on tooth enamel. The study is in the journal Langmuir.
氟化物有抵抗蛀牙的功效 。这就是为什么它会出现在饮用水和牙膏里 。然而，这种矿物质是如何施展魔法来保护牙齿至今仍是个谜 。如今，研究人员提供了一个具体的解决方案 。他们发现氟处理能缓解牙釉质里细菌的压力 。这项研究发表在《朗缪尔》期刊上 。
Scientists used to think that fluoride could harden tooth enamel, helping it retain the minerals that protect teeth from the acid produced by our oral flora. But recent work has shown that fluoride doesn't really penetrate past the tooth's thinnest outer layer, suggesting that something other than hardening is going on.
科学家们曾认为氟化物能够坚固牙釉质，这样有助于保留矿物质，进而使牙齿不被口腔内细菌分泌的酸所腐蚀 。但近期的研究显示氟化物并不能穿透牙齿的最薄的外层，这说明氟化物不仅能坚固牙齿，而且还有其它作用 。
To drill deeper into this toothsome mystery, researchers whipped up a set of artificial choppers, made of the same stuff as teeth. And they used atomic force microscopy to take a closer look at how bacteria interact with this dental material. They found that three different strains of cavity-causing bugs cling less tightly to enamel that's been rinsed with fluoride.
为了发掘更多牙齿的奥秘，研究人员设计了一套人工的假牙，这套假牙是由与真牙相同的物质做成的 。他们利用原子力显微镜近距离观察了细菌如何与牙齿材料进行互动 。他们发现引起蛀牙的三种不同的菌株很少粘附于有氟化物加固的牙釉质表面 。
The bacteria carry a net negative charge on their surfaces. So the negatively charged fluoride ions in the treated enamel may be literally repulsive to the bacteria. Which causes them to bite the dust.
细菌的表面带有一个负电荷 。牙釉质里的氟离子也带负电荷，因此二者自然互相排斥，这让蛀牙细菌败下阵来 。