As your baby teeth feel those adult teeth growing in behind them, their root dissolves and they fall out.

当你的乳牙感觉到后面恒牙在生长，它们的根部开始溶解，然后它们就脱落了。

That is tricky, because enamel-making cells, known as ameloblasts, disappear soon after a person's adult teeth have finished growing.

这是一个棘手的问题，因为牙釉质生成细胞，即成釉细胞，在人的成年牙齿生长完成后很快就会消失。

I still had baby teeth, and I had my teeth pulled so that the adult teeth could come in.

我还有乳牙，然后我把牙齿拔了，这样恒牙才能长出来。

As we mature, our baby teeth drop out, replaced by adult teeth.

当我们长大，乳牙脱落，取而代之的是恒牙。

After losing their baby teeth, plant-eating mammals like this antelope have one set of tall, adult teeth.

在失去乳牙后，像这只羚羊这样的食草哺乳动物长出了一套高大的成年牙齿。

Mammals have one set of baby teeth that are replaced in youth by a final set of adult teeth.

哺乳动物有一组乳牙，它们在年轻时被最后一组成年牙取代。

But too much fluoride, especially for children who's adult teeth are still forming can lead to a problem called dental fluorosis when white patches form on teeth.

但是过多的氟化物，尤其是对于儿童来说，成年人的牙齿还在形成阶段，当牙齿上形成白色斑块时，就会导致一种叫做氟斑牙的问题。

But after those adult teeth grow in, all the stem cells that laid down the crystal nanorods self-destruct, so that's the only set of replacement teeth you get.

但当这些恒牙长出后，所有生成纳米结晶体的干细胞就会自我消亡，所以你只能有这一副替换牙。

He lost his first adult tooth when he was 22, and by the time he was president he had only one real tooth left.

他在 22 岁时失去了第一颗成年牙齿，到他担任总统时， 他只剩下一颗真牙。

In Japan, children throw a lower baby tooth up onto the roof so the next tooth grows healthily upwards; an upper tooth goes under the house so the new adult tooth grows downwards.

在日本，孩子会把下齿的乳牙放到房顶上，这样的话下颗牙将会长得结结实实；上齿牙会扔到地上，这让孩子的上齿牙会往下健康地成长。

In the lab, adult teeth soaked in white wine for a day suffered a loss of both calcium and a mineral called phosphorus to depths of up to 60 micrometers in the enamel surface, which the researchers say is significant.

实验室中，浸泡在白葡萄酒中的恒牙（成年牙）60微米的表层牙釉质中出现了钙元素和矿物元素磷的流失。研究人员称这种腐蚀程度算是严重的了。