Also curious about this. I'd be shocked if TMJ/TMD was more than incidentally psychological. Mine is definitely a mix of genetics (thanks Dad!) and inflammatory. When I started Humira for unrelated reasons, the painful aspects cleared right up... although as I type this comment I just realized the recent resurgence in pain might have to do with how Humira's been less effective for me lately :P
EDIT: Ah, just saw the other reply. Strange.