The use of fluoride to protect teeth is common in many parts of the world.

VOA: special.2009.03.11

I move out of the room toward the bathroom, planning to brush my teeth. As I enter the bathroom, it's much more light, I look in the mirror and-- here's where things get really weird--I don't see anything.

我离开卧室走向浴室,要去刷牙,当我走进浴室时,光线明亮了些,我看着镜子,从这里情节就诡异了,我什么也没看到

耶鲁公开课 - 死亡课程节选

The sneer is gone from Casey's lip, his teeth are clinched in hate;

VOA: special.2011.04.04

Bob Thompson says the free clinic was the only way he could get help for his teeth, which were damaged in an accident.

VOA: standard.2009.06.13