This is the 6955th most frequent Chinese word.
牙齿
Teeth.
In this sentence, '牙齿' (teeth) is used to refer to the parts of the body that are cleaned during brushing.
我每天早上刷牙齿。
I brush my teeth every morning.
Here, '牙齿' is used to describe the subject of pain that necessitates medical attention.
牙齿痛时可以去看牙医。
When your teeth hurt, you can visit a dentist.
In this instance, '牙齿' refers to the emerging teeth of a child.