Vader is a sick puppy. You will not see Dr. Doom going around like this:

Update: Oh, yeah, and which school did this guy get his doctorate from?

that's just wrong.

At least Vader doesn't have to pretend to be a doctor to get respect!

I don't think Dr. Teeth's after respect or fear. I'm sure he just wants the good drugs.

Or has them, since he's the 'Dr.' Probably an advanced pharmacy/music degree then. I think Mason Gross gives those out.