如果你用盐或小苏打来美白牙齿，或许你应该停止了

If you regularly enjoy coffee, tea, red wine and pastas with marinara sauce, you might be aware that these foods and beverages leave behind stains on your teeth well after they are consumed.

如果你经常喜欢喝咖啡、茶、红酒和意大利面配番茄酱，你可能会意识到这些食物和饮料在你吃完之后会在牙齿上留下污渍。

But if you think you've found a whitening solution in the form of table salt (sodium chloride) or baking soda (another type of salt, sodium bicarbonate), think again.

但是，如果你认为你已经找到了一种以食盐(氯化钠)或小苏打(另一种盐，碳酸氢钠)为形式的美白溶液，那你就错了。

"I see no clinical reason why someone would brush their teeth with salt," said Dr. Matt Messina, an Ohio-based dentist and assistant professor at the Ohio State University College of Dentistry. "There is no scientific evidence that brushing with salt has any sort of whitening effect on teeth."

“我看不出有人用盐刷牙的临床原因，”俄亥俄州牙医、俄亥俄州立大学牙医学院助理教授马特·梅西纳博士说。“没有科学证据表明，用盐刷牙对牙齿有任何美白效果。”

The same can be said for baking soda, although there is more of a scientific basis to the value of using sodium bicarbonate to brush your teeth, Messina explained. It's a mild abrasive, and chemically also a mild bleach, which can neutralize cavity-causing acids. So when commercially available toothpaste didn't exist, he said, baking soda made sense for its ability to polish teeth and reduce acidity.

同样的道理也适用于小苏打，尽管使用碳酸氢钠刷牙的价值有更多的科学依据，梅西纳解释说。它是一种温和的研磨剂，化学上也是一种温和的漂白剂，可以中和蛀牙引起的酸。他说，所以当市面上还没有牙膏的时候，小苏打对于打磨牙齿和减少酸性的能力是有意义的。

But that was then; today, you've got better options. In fact, exposing teeth to salt or baking soda could erode the tooth's surface enamel over time. Enamel is like the finished surface of a floor: It's a thin, hard outer layer that protects each tooth. When enamel is worn away by an irritant, such as salt, decay can occur as bacteria in plaque are able to penetrate teeth more quickly, where they produce acids that can lead to cavities.

但那是过去的事了;今天，你有更好的选择。事实上，长时间暴露在盐或小苏打中会腐蚀牙齿表面的牙釉质。牙釉质就像地板的表面:它是一层薄薄的、坚硬的外层，保护着每颗牙齿。当牙釉质被一种刺激物(如盐)腐蚀时，牙菌斑中的细菌能够更快地穿透牙齿，从而产生酸，导致蛀牙。

Nerve damage can occur as well, and gums may become more sensitive, explained Dr. Gerald Grossman, a New York-based cosmetic dentist and diplomate of the American Board of Aesthetic Dentistry.

也会发生神经损伤，牙龈可能会变得更加敏感，纽约的美容牙医、美国牙科美容委员会的医师杰拉尔德·格罗斯曼博士解释说。

Since salt and baking soda are abrasive they could remove stains from teeth, but that's like trying to lighten your floors by sanding them down, said Messina, who is also a spokesperson for the American Dental Association. It'll work -- but eventually you'd sand away the floor's entire surface.

同时也是美国牙科协会发言人的梅西纳说，由于盐和小苏打具有研磨性，它们可以去除牙齿上的污渍，但这就像试图通过打磨来减轻牙齿的重量。它会起作用——但最终你会磨掉牙齿的整个表面。

"You might see short-term whitening with an abrasive, as it will remove surface stains and teeth may get whiter quickly, but the long-term damage is in no way worth that," Messina said. The erosion of enamel can also cause teeth to become more yellow over the long-term, as the yellow-colored dentin, the inner layer of tooth, is exposed.

梅西纳说:“你可能会看到用研磨剂进行短期美白，因为它可以去除表面的污渍，牙齿可能很快变白，但长期的损害是不值得的。”牙釉质的腐蚀也会导致牙齿长期变黄，因为牙齿内层黄色的牙是暴露在外的。

There's no way to know how much is too much scrubbing with salt, because everybody's case is different, Messina explained. "But enamel doesn't grow back ... once it's gone, it's gone."

梅西纳解释说，因为每个人的情况都不同，所以无法知道用盐擦洗多少次才算多。“但是牙釉质不会再长出来……一旦它消失了，它就消失了。”

The best way to whiten teeth

美白牙齿的最佳方法

To keep your teeth as white as possible, it's important to brush and clean between your teeth and floss on a regular basis with a toothpaste approved by the American Dental Association. "Clean teeth are whiter and healthier," Messina said.

为了让你的牙齿尽可能洁白，用美国牙科协会认可的牙膏定期刷牙和清洁牙线是很重要的。“清洁的牙齿更白更健康，”梅西纳说。

If regular brushing and flossing isn't giving you the results you want, Messina recommend a personalized, in-office consultation with a dentist. "There are safe and effective whitening techniques, but they will be different for each individual person," Messina said.

如果经常刷牙和使用牙线不能达到你想要的效果，梅西纳建议向办公室的牙医进行个性化咨询。梅西纳说:“现在有安全有效的美白技术，但它们因人而异。”