It is a noun, and it means a thorough medical or dental examination.

它是个名词，意思是彻底的体检或牙检。

But whilst armadillos and sloths do have rudimentary teeth, if you were to perform a dental examination on one of these guys, which would be difficult because their mouth is so small, you'd find no teeth at all.

但犰狳和树懒有退化的牙齿，如果你给其中一个家伙做牙科检查，就会发现的但是这很困难，因为它们的嘴太小，你会发现根本就找不到牙齿。