It's almost bed time here at the fort!
城堡里差不多要到睡觉时间啦!
But before we get tucked in, we've got to brush our teeth!
但是在我们睡觉之前,得先刷牙!
Hey, that's a good question, Squeaks.
嘿,这是个好问题,小老鼠。
We do it a couple of times a day, but we should really understand why we do it!
我们一天刷好几次牙,但是我们应该真正了解为什么要这样做!
So: Why do we have to brush our teeth?
所以:我们为什么必须刷牙呢?
Well, have your teeth ever felt just. . . yucky?
好吧,你的牙齿有没有感觉恶心过?
Like at the end of the day?
比如说晚上的时候?
Or first thing in the morning?
或者早晨起来的时候?
I really like brushing my teeth, because it gets rid of that icky feeling.
我真的很喜欢刷牙,因为这样可以消除那种恶心的感觉。
And it feels good, because it is good!
而且刷牙的感觉也很好,因为它带来好处!
We brush our teeth to keep them clean and healthy--so they can keep helping us our whole lives!
我们刷牙来保证牙齿的干净和健康——这样它们就可以帮助我们一辈子!
After all, how would you crunch up a cracker, or bite into an apple, without them?
毕竟,没有牙齿,你要怎么嚼饼干、咬苹果呢?
Without teeth, you'd have very few choices of foods that you could eat.
没有了牙齿,你能选择的食物就很少了。
So you've got to take care of them!
所以你必须照顾好牙齿!
Now, you can't tell just by looking at them, but your teeth are actually made of up different layers.
现在,你光看牙齿是看不出来什么的,但它实际上是由不同的层次构成的。
The part that you can see -- on the outside -- is super hard shell called enamel, which is mostly made of minerals.
外面你能看到的部分是超级坚硬的外壳,称为釉质,主要成分是无机物。
Enamel is the strongest stuff in your whole body -- even stronger than bone!
牙釉质是全身最坚硬的东西,甚至比骨头还硬。
But unlike your bones, a tooth can't heal itself if it's broken.
但是和骨头不同,如果牙齿破损了就没法自愈。
And your teeth aren't hard enamel all the way through.
并且牙齿并不是全都是牙釉质。
Just below that tough outer layer, there's another layer called dentin that's not as hard. And below that, there's the inner layer of the tooth, called the pulp, which has blood vessels and nerves inside it.
在这层坚硬的外层下,还有另一层物质叫做牙本质,它没有牙釉质坚硬。牙本质下面是牙齿的内层,叫做牙髓,里面有血管和神经。
And this part of your tooth is super sensitive.
牙髓这部分非常敏感。
So in order to protect the delicate pulp inside of your teeth, you have take really good care of the outside.
所以,为了保护牙齿内部脆弱的牙髓,你必须好好保护牙齿外层。
And the best way to do that, is to clean them up after you eat.
而最好的保护方式就是吃完食物以后清洁牙齿。
Because food can damage even those tough outer layers of your teeth. How?
因为食物甚至能够损坏那些坚硬的牙齿外层。怎么做到的呢?
Well, you might think that you ate every last bite of those crackers that you had as a snack, but the truth is, some very small pieces of food are still hanging around in your teeth!
好吧,你可能认为你把零食小饼干的每一口都咽下去了,但事实是,一些非常小的食物残渣仍然挂在你的牙齿上。
That's because your teeth aren't all shiny and smooth.
那是因为你的牙齿并不全是闪亮光滑的。
They have lots of bumps and ridges that help you grind down your food.
牙齿有很多凸起,可以帮你磨碎食物。
And there are lots of small spaces between them too.
但是牙齿之间有许多小缝隙。
These are places where it's easy for food to get stuck and hang out all day.
这些地方很容易卡住食物,然后一整天都在那里。
Which is kind of gross!
有点恶心!
But you know what's even more gross?
但是你知道什么是更恶心的吗?
You're not the only one enjoying those leftovers.
你不是唯一一个享受这些剩菜残渣的人。
There are lots of tiny little things that call your mouth home.
还有很多小东西在你的嘴里安家。
These are called bacteria.
这些小东西叫细菌。
They're way too small to see, but they're definitely in there.
它们小到根本看不见,但是肯定存在。
And there are a lot of them!
而且还有很多!
In just your mouth alone, there are more bacteria than there are people on earth.
光是嘴巴里,就有比地球上人口还多的细菌。
Some kinds of bacteria are really good to have!
有些细菌确实是有益的!
Others just kind of hang around, and are neither good nor bad.
还有些细菌只是徘徊着,既无益也无害。
And then there are some who are pretty bad house guests, and you don't want them staying in your mouth for too long.
然后,还有一些非常糟糕的“客人”,你不会想让它们在你的嘴里呆太久的。
One type of bacteria loves to eat the same stuff that you do -- especially sugars and starches -- that means things like cookies, chips, bread, candy, and cereal.
这种细菌喜欢跟你吃一样的东西,尤其是糖和淀粉,也就是饼干、薯片、面包、糖果和麦片。
These bacteria hang around on your teeth and in your mouth, basically eating your leftovers!
这些细菌在你的牙齿和口腔里徘徊,基本上是在吃剩菜残渣。
And once they're done with those tiny bits of food, they release acid, which can really hurt your teeth!
一旦细菌吃完这些微小的食物,它们就会释放出酸,这真的会伤害到你的牙齿。
This acid can cause holes, called cavities, to form in the enamel of your teeth.
这些酸会造成蛀牙洞,形成在牙釉质表面。
And cavities can really hurt!
蛀牙真的很疼!
They might even make it hard for you to eat if they get too big.
如果蛀牙洞太大,甚至可能会让你吃不下去东西。
But the good news is that when you brush your teeth, you clean away the food that those bacteria love so much, and you sweep away some of the bacteria themselves.
但好消息是,当你刷牙的时候,就把那些细菌喜欢的食物都刷掉了,同时也刷掉了一些细菌。
And with them goes that icky, gross feeling on your teeth.
跟它们一起刷掉的,还有牙齿上的恶心感。
So, we brush our teeth before we go to bed, to get rid of all those tiny bits of food we've eaten during the day, and to clean out the bacteria that are hiding in our mouths.
所以,我们在睡前要刷牙,清理白天吃过的食物残渣和隐藏在口腔中的细菌。
Fewer bits of food in there, and fewer bacteria, mean you have less of a chance of getting cavities!
食物残渣和细菌越少,得蛀牙的几率就越小。
But! You should brush your teeth in the morning, too!
但是!早上也需要刷牙!
Because: even though you brushed the night before, there are always some bacteria sticking around in your mouth.
因为:即使你晚上刷过牙了,你的嘴里还是会有残留的细菌。
And while you were sleeping, those little guys were partying it up!
在你睡觉的时候,这些细菌就在嘴里狂欢起来了!
So when you brush in the morning, you're starting the day off with a nice, clean mouth.
所以早上刷完牙之后,你就能以干净的口腔开始一天的生活。
That's why you should brush your teeth at least twice a day -- in the morning and at bedtime!
这就是为什么每天至少要刷两次牙——起床后和睡觉前。
Taking care of your teeth will make sure that they stay strong and healthy, so you can keep eating good food -- which keeps the rest of you healthy!
照顾好你的牙齿,确保它们坚硬又健康,这样你就可以继续吃好吃的食物,这样也保证了身体其他器官的健康!
Once our teeth are clean, it'll be time for us to head to bed.
牙齿刷干净啦,该上床睡觉了。
We do a couple of times a day.