incisor

Rodents have sharp incisors that grow continuously throughout their lives.

(Chinese) 啮齿类动物拥有锋利的门牙，这些牙齿在它们的一生中会不断生长。

He chipped his upper incisor after accidentally biting onto a hard peach pit.

(Chinese) 他不小心咬到坚硬的桃核后，崩掉了一块上门牙。