挑选牙膏需要注意什么

Fancy toothpastes may come in different colors and boast unusual ingredients, but they probably don't offer better dental health than the average drugstore toothpaste. Here's what to look for if you try a new brand:
高档牙膏可能有不同的颜色、独特的成分，但它们对牙齿健康所起的作用并不一定比药店售卖的普通牙膏更好。如果你想换个牌子，应注意下列事项。

Abrasives
磨擦剂

Toothpastes provide a little mechanical help with scrubbing; that's the main reason they exist. Particles of grit help to scrape bacterial plaque from your teeth. Some common abrasives include calcium carbonate, silica, aluminum oxide, and magnesium carbonate. Charcoal can also act as an abrasive, but some dentists caution that charcoal can be too harsh.
牙膏中的粉状磨擦剂在牙刷来回抽动下机械地刷除牙渍，所以牙膏会含有磨擦剂。磨擦颗粒有助于刷除牙菌斑。常见的磨擦剂包括碳酸钙、二氧化硅、氧化铝和碳酸镁。木炭也可以用作磨擦剂，但有些牙医警告称，木炭可能太过刺激

Fluoride or (maybe) an alternative
氟化物或可能的替代品

Bacteria are constantly dissolving your teeth, and your teeth are constantly trying to build themselves back up. (Your saliva naturally contains calcium to aid in this process.) This process, called remineralization, is helped along by fluoride. All toothpastes that have an American Dental Association seal must contain fluoride.
细菌不断地破坏你的牙齿，所以牙齿会不断地试图回到最佳状态。（我们的唾液本身含钙，可辅助这一过程。）这一过程也被称为再矿化，会在氟化物的帮助下进行。所有盖着美国牙科协会印章的牙膏必须含氟化物。

Some brands now are using hydroxyapatite instead. Research shows that hydroxyapatite may be as good as fluoride for remineralizing teeth, but the science isn't yet solid enough for most dentists to recommend it. If you have a specific reason why you need to avoid fluoride, ask your dentist about hydroxyapatite; but for now, most of us should probably stick with fluoride toothpastes.
现在，有些牙膏品牌正使用羟基磷灰石替代氟化物。研究表明，在牙齿再矿化方面，羟基磷灰石或起到与氟化物一样的作用，但研究尚不足以让大多数牙医推荐羟基磷灰石。如果你因为特殊原因不能使用氟化物，可询问牙医是否可以使用羟基磷灰石；但目前为止，大多数人仍使用含氟牙膏。

Ingredients for texture and flavor
关于牙膏质地和味道的成分

Everything else is just there to make the toothpaste easy to use. Humectants help the substance to keep a gel-like texture; foaming agents make it bubble up as you brush. Toothpastes that are missing these ingredients can still do a fine job of cleaning your teeth. (I use a toothpaste with no foaming agents and prefer it.)
除了以上两条，其它的成分都是让牙膏更容易使用。保湿剂有助于使牙膏保持凝胶状质地；发泡剂会让你在刷牙时起泡泡。没有这些成分的牙膏仍能很好地清洁牙齿（我用的牙膏没有发泡剂，我很喜欢。）

Flavorings are flavorings, and sweeteners are now typically artificial sweeteners like saccharine. Toothpastes can't get the ADA seal of approval if they contain sugar. I swear I am not in the pocket of Big Dental, but personally I'd rather use the ADA-approved stuff in the drugstore than a trendy new brand, however photogenic.
牙膏有各种各样的味道是因为添加了调味剂。现在使用的甜味剂通常都是人造的，比如糖精。含有糖分的牙膏不会被盖上美国牙科协会的印章。我发誓，我一点儿都不喜欢Big Dental，但个人层面而言，我更愿意使用药店里经美国牙科协会认证的牙膏，而不会选择广告满天飞的潮流品牌。