I have TMJ problems. I grind and clench in my sleep, and if I have a stressful day at work, I can feel myself clench even at work.
The headaches that can come from this are awful! I also have popping in my jaw that comes and goes--it is worse on days when I have been very stressed out.
I use the NTI nightguard. It is expensive, but it is different, in the respect that it helps with both grinding and clenching.
I wish I knew if there was a direct correlation between Crohn's and getting TMJ problems. It would be interesting to know.
Good luck and I hope you find help and relief soon as TMJ problems can be very painful!