at an initial consult, these are some of the things a dentist commonly does:
+ measures how wide you can open as well as how wide you can move to the sides.
+ muscle palpatation inside the mouth and on the face
+ listen to/feel the TMJs to see if there's any clicking, pain
+ asks about your medical history
+ asks about your current symptoms, if they've changed, etc
+ might do tomograms, xrays, joint vibration analysis, EMG
that's all i can think of right now..