Decided to draw up a little diagram of manipulator teeth. o3o Being that I'm a biting fan, and all. ;)

So, the fangs at front are metal. I couldn't really fit this in there, but they vibrate, which is good for cutting things :3

Back teeth are also metal.

Manipulators have big, crocodile-like throats, and can fit human-sized prey down their gullets. Whole. though, usually, they'll cut it up and eat little chunks.