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When a team of archaeologists recently came across some 15,000 year-old human remains,
当最近一群考古学家发掘出将近15000年前的人类骸骨时，
they made an interesting discovery.
他们有了一个有趣的发现。
The teeth of those ancient humans were riddled with holes.
这些远古人的牙齿上有许多蛀洞。
Their cavities were caused by the same thing that still plagues us today, specific tiny microbes that live in our mouths.
他们蛀牙的罪魁祸首和今天折磨我们的东西一样，那就是生活在我们口中的某些细菌。
These microbes are with us soon after birth.
这些细菌从出生时就开始伴随着我们。
We typically pick them up as babies from our mothers' mouths.
一般而言，它们是从母亲的口中传给孩子的。
And as our teeth erupt, they naturally begin to accumulate communities of bacteria.
当我们的牙齿开始生长时，它们便开始形成菌落。
Depending on what we eat, and specifically how much sugar we consume,
我们所吃的食物和我们所摄入的糖分，
certain microbes can overpopulate and cause cavities.
可以使得某些细菌过度增殖并形成龋齿。
Diets high in sugary foods cause an explosion of bacteria called mutans streptococci in our mouths.
高糖饮食会导致我们口中一种叫做变形链球菌的细菌爆发式的增长。
Like humans, these microorganisms love sugar, using it as a molecular building block and energy source.
就像人类一样，这些微生物喜欢糖类，并将糖作为生长的基石和能量的来源。
As they consume it, the bacteria generate byproducts in the form of acids, such as lactic acid.
当细菌消耗糖类时，它们会产生一种酸性的副产品，比如乳酸。
Mutans streptococci are resistant to this acid, but unfortunately, our teeth aren't.
变形链球菌可以免疫乳酸的腐蚀，然而不幸的是，我们的牙齿并不可以。
While each human tooth is coated in a hardy, protective layer of enamel, it's no match for acid.
尽管我们每个人的牙齿上都有一层质地坚硬，可以起到保护作用的牙釉质，但是这仍不是酸的对手。
That degrades the armor over time, leaching away its calcium minerals.
随着时间的推移，酸会侵蚀这层盔甲，溶解其中的钙元素。
Gradually, acid wears down a pathway for bacteria into the tooth's secondary layer called the dentin.
渐渐地，酸会为细菌侵蚀出一条通道，直达被称作牙本质的牙齿内层。
Since blood vessels and nerves in our teeth are enclosed deep within, at this stage, the expanding cavity doesn't hurt.
因为牙齿的血管和神经都被保护在最深处，在这个阶段，逐渐扩大的龋齿并不会造成痛感。
But if the damage extends beyond the dentin,
但是当细菌侵蚀超过牙本质的范围，
the bacterial invasion progresses causing excruciating pain as the nerves become exposed.
神经就会被暴露，同时形成强烈痛感。
Without treatment, the whole tooth may become infected and require removal all due to those sugar-loving bacteria.
如果不加治疗，整颗牙齿就会受到感染并且需要拔除，这都是由那些好糖类细菌导致的。
The more sugar our food contains, the more our teeth are put at risk.
摄入食物中的糖分越多，牙齿受到的威胁就越大。
Those cavemen would hardly have indulged in sugary treats, however, so what caused their cavities?
然而，那些山顶洞人几乎不会饕餮甜食盛宴，那么他们的龋齿是什么造成的呢？
In meat-heavy diets, there would have been a low-risk of cavities developing
在多肉的饮食中，形成龋齿的风险较小，
because lean meat contains very little sugar, but that's not all our early human ancestors ate.
因为瘦肉中包含很少的糖分，但是我们的祖先不仅仅只吃瘦肉。
Cavemen would also have consumed root vegetables, nuts, and grains, all of which contain carbohydrates.
山顶洞人还会吃根类蔬菜、坚果和谷物，这些食物都包含碳水化合物。
When exposed to enzymes in the saliva, carbohydrates get broken down into simpler sugars,
当碳水化合物暴露在唾液中酶的环境时，它们便会被分解更为简单的糖，
which can become the fodder for those ravenous mouth bacteria.
这为那些贪婪的细菌提供了养分。
So while ancient humans did eat less sugar compared to us, their teeth were still exposed to sugars.
所以尽管我们的祖先相较我们摄入了更少的糖分，但他们的牙齿仍暴露在糖分之中。
That doesn't mean they were unable to treat their cavities, though.
虽然如此，这并不代表他们不能治疗龋齿。
Archaeological remains show that about 14,000 years ago,
考古遗迹显示在约14000年前，
humans were already using sharpened flint to remove bits of rotten teeth.
人类已经会使用磨尖的燧石去除烂牙。
Ancient humans even made rudimentary drills to smooth out the rough holes left behind
远古人甚至做了最原始的钻头，用于磨平留下的粗糙的龋洞，
and beeswax to plug cavities, like modern-day fillings.
并将蜂蜡注入蛀孔，就如今天的填充物一样。
Today, we have much more sophisticated techniques and tools,
如今，我们有了更加成熟的技术和工具，
which is fortunate because we also need to contend with our more damaging, sugar-guzzling ways.
这是非常幸运的，因为我们需要面对更具破坏性的更多糖分的饮食。
After the Industrial Revolution, the human incidence of cavities surged
工业革命后，人类龋齿发生率飙升，
because suddenly we had technological advances that made refined sugar cheaper and accessible.
这是因为突然之间我们有了更加先进的技术，使得精炼糖变得更加便宜和易得。
Today, an incredible 92% of American adults have had cavities in their teeth.
今天，92%的美国成年人有龋齿问题，难以置信。
Some people are more susceptible to cavities due to genes that may cause certain weaknesses, like softer enamel,
某些人由于基因更易形成龋齿，这些基因会导致如更软的牙釉质等问题，
but for most, high sugar consumption is to blame.
但是对于大多数人而言，高糖的摄入才是罪魁祸首。
However, we have developed other ways of minimizing cavities besides reducing our intake of sugar and starch.
但是，我们已经发展出了降低糖类和淀粉摄入之外减少龋齿的办法。
In most toothpastes and many water supplies, we use tiny amounts of fluoride.
在大部分的牙膏和自来水中，我们添加了少量的氟化物。
That strengthens teeth and encourages the growth of enamel crystals that build up a tooth's defenses against acid.
氟化物可以增强牙齿并促使牙釉质生长以抵抗酸的侵蚀。
When cavities do develop, we use tooth fillings to fill and close off the infected area,
当龋齿已经产生时，我们利用牙齿填充物去填补并封闭被感染区域，
preventing them from getting worse.
防止它们朝着更坏的方向发展。
The best way to avoid a cavity is still cutting down on sugar intake
然而，预防龋齿的最佳方式仍是降低糖分摄入，
and practicing good oral hygiene to get rid of the bacteria and their food sources.
形成良好的口腔卫生，以消除细菌和它们的食物来源。
That includes regular tooth brushing, flossing,
这包含日常的刷牙、剔牙，
and avoiding sugary, starchy, and sticky foods that cling to your teeth between meals.
避免摄入糖类、淀粉和在各餐之间会附着于牙齿上的粘性食物。
Gradually, the population of sugar-loving microbes in your mouth will decline.
渐渐地，口腔中的好糖类细菌便会减少。
Unlike the cavemen of yesteryear, today we have the knowledge required to avert a cavity calamity.
和以前的山顶洞人不同，今天的我们拥有更多预防龋齿的知识。
We just need to use it.
我们只需运用它。
