TED精选|What cause cavities?

最近，一组考古学家在发现大约15，000年前的人类遗骸时，有了一个有趣的发现：这些古人的牙齿上布满了洞。那么，是什么原因导致蛀牙，我们如何避免它们呢？跟小青一起来了解了解吧！

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When a team of archaeologists recently came across some 15,000 year-old human remains, they made an interesting discovery.

最近，当一组考古学家发现大约15，000年前的人类遗骸时，他们发现了一个有趣的发现。

The teeth of those ancient humans were riddled with holes.

那些古人的牙齿上布满了洞。

Their cavities were caused by the same thing that still plagues us today, specific tiny microbes that live in our mouths. These microbes are with us soon after birth. We typically pick them up as babies from our mothers' mouths. And as our teeth erupt, they naturally begin to accumulate communities of bacteria. Depending on what we eat, and specifically how much sugar we consume, certain microbes can overpopulate and cause cavities. Diets high in sugary foods cause an explosion of bacteria called mutans streptococci in our mouths.

他们的蛀牙是由今天仍然困扰着我们的同一件事引起的，特定的微小微生物生活在我们的嘴里。这些微生物出生后不久就和我们在一起了。我们通常从母亲的嘴里把它们当婴儿来接。当我们的牙齿爆发时，它们自然地开始积累细菌群落。根据我们吃什么，特别是我们消耗多少糖，某些微生物会过度进食并导致蛀牙。高含糖食物的饮食会导致我们嘴里的细菌爆炸，称为粘膜链球菌。

Like humans, these microorganisms love sugar, using it as a molecular building block and energy source. As they consume it, the bacteria generate byproducts in the form of acids, such as lactic acid. Mutans streptococci are resistant to this acid, but unfortunately, our teeth aren't. While each human tooth is coated in a hardy, protective layer of enamel, it's no match for acid.

和人类一样，这些微生物喜欢糖，把它作为分子构建块和能量来源。当细菌食用它时，它们会以酸的形式产生副产品，如乳酸。穆坦链球菌对这种酸有抵抗力，但不幸的是，我们的牙齿没有。虽然每个人的牙齿都涂有坚硬的保护层釉质，但它与酸不匹配。

That degrades the armor over time, leaching away its calcium minerals. Gradually, acid wears down a pathway for bacteria into the tooth's secondary layer called the dentin. Since blood vessels and nerves in our teeth are enclosed deep within, at this stage, the expanding cavity doesn't hurt. But if the damage extends beyond the dentin, the bacterial invasion progresses causing excruciating pain as the nerves become exposed. Without treatment, the whole tooth may become infected and require removal all due to those sugar-loving bacteria.

随着时间的推移，这会降低盔甲的降解，使其钙矿物质消失。渐渐地，酸会沿着细菌进入牙齿的次生层（称为牙龈）的途径消失。由于我们牙齿中的血管和神经被封闭在深处，在这个阶段，扩张的腔不会伤害。但是，如果损害延伸到丹汀之外，细菌入侵会随着神经暴露而造成剧烈的疼痛。如果不进行治疗，整颗牙齿可能会被感染，并且由于这些嗜糖细菌从而需要被全部拔除。

The more sugar our food contains, the more our teeth are put at risk.

我们的食物含的糖越多，我们的牙齿就越处于危险之中。

Those cavemen would hardly have indulged in sugary treats, however, so what caused their cavities? In meat-heavy diets, there would have been a low-risk of cavities developing because lean meat contains very little sugar, but that's not all our early human ancestors ate. Cavemen would also have consumed root vegetables, nuts, and grains, all of which contain carbohydrates. When exposed to enzymes in the saliva, carbohydrates get broken down into simpler sugars, which can become the fodder for those ravenous mouth bacteria. So while ancient humans did eat less sugar compared to us, their teeth were still exposed to sugars. That doesn't mean they were unable to treat their cavities, though.

然而，那些穴居人几乎不会沉溺于含糖的食客，那么是什么导致了他们的蛀牙呢？在肉类含量高的饮食中，由于瘦肉中糖含量很低，因此蛀牙形成的风险会很低，但这并不是我们早期人类祖先吃的所有食物。穴居人也会食用根类蔬菜、坚果和谷物，所有这些都含有碳水化合物。当暴露在唾液中的酶中时，碳水化合物会分解成更简单的糖，这可以成为那些贪婪的口腔细菌的饲料。因此，虽然古人吃的糖比我们少，但他们的牙齿仍然接触糖。不过，这并不意味着他们无法治疗自己的蛀牙。

Archaeological remains show that about 14,000 years ago, humans were already using sharpened flint to remove bits of rotten teeth. Ancient humans even made rudimentary drills to smooth out the rough holes left behind and beeswax to plug cavities, like modern-day fillings. Today, we have much more sophisticated techniques and tools, which is fortunate because we also need to contend with our more damaging, sugar-guzzling ways. After the Industrial Revolution, the human incidence of cavities surged because suddenly we had technological advances that made refined sugar cheaper and accessible.

考古遗迹显示，大约14，000年前，人类已经使用锋利的火石来去除一些腐烂的牙齿。古人类甚至做了基本的钻头，以抚平留下的粗糙的洞和蜜蜂蜡堵塞腔，如现代填充物。今天，我们有更先进的技术和工具，这是幸运的，因为我们还需要对付我们更具破坏性的，含糖量大的方法。工业革命后，人类蛀牙的发病率急剧上升，因为我们突然有了技术进步，使精制糖更便宜，更容易获得。

Today, an incredible 92% of American adults have had cavities in their teeth. Some people are more susceptible to cavities due to genes that may cause certain weaknesses, like softer enamel, but for most, high sugar consumption is to blame.

今天，令人难以置信的92%的美国成年人的牙齿有蛀牙。有些人更容易受到蛀牙的影响，因为基因可能导致某些弱点，如较软的釉质，但对大多数人来说，高糖消费是罪魁祸首。

However, we have developed other ways of minimizing cavities besides reducing our intake of sugar and starch. In most toothpastes and many water supplies, we use tiny amounts of fluoride. That strengthens teeth and encourages the growth of enamel crystals that build up a tooth's defenses against acid. When cavities do develop, we use tooth fillings to fill and close off the infected area, preventing them from getting worse. The best way to avoid a cavity is still cutting down on sugar intake and practicing good oral hygiene to get rid of the bacteria and their food sources. That includes regular tooth brushing, flossing, and avoiding sugary, starchy, and sticky foods that cling to your teeth between meals. Gradually, the population of sugar-loving microbes in your mouth will decline.

然而，除了减少糖和淀粉的摄入量外，我们还开发了其他方法来尽量减少蛀牙。在大多数牙膏和许多供水中，我们使用少量的氟化物。这加强了牙齿，并鼓励牙釉质晶体的生长，建立牙齿对酸的防御。当蛀牙确实发展，我们使用牙齿填充物来填充和关闭感染区，防止他们变得更糟。避免蛀牙的最好方法仍然是减少糖的摄入量，并实行良好的口腔卫生，以消除细菌及其食物来源。这包括定期刷牙、牙线和避免在两餐之间粘在牙齿上的含糖、淀粉和粘性食物。渐渐地，嘴里爱糖的微生物数量将会减少。

Unlike the cavemen of yesteryear, today we have the knowledge required to avert a cavity calamity. We just need to use it.

与往年的穴居人不同，今天我们有了避免空腔灾难所需的知识。我们只需要使用它。

REC

图文来源|TED TALK

编辑|青年传媒中心 何珺

责编|青年传媒中心 余心雨

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