The TMJ is that joint where your jaw is attached to the upper part of your skull
When I asked my GP doctor about the problem years ago he said there were three courses of action. One was just leave it alone, the second involved taking anti-inflammatories, and the third and worst to me was an injection into the joint. I assume that would have been a cortisone injection. It was a horrifying thought then so I took the "leave it alone" route.
Twelve months ago and a generation later I saw a rheumatology Fellow. He asked about the asymmetry of my face. (News to me!) He and the rheumatologist conferred and sent me for a CT scan. A few weeks later I got a bad news call from my specialist - actually the first call ever. He said that my jaw joint has severe degeneration on one side and moderate degeneration on the other.
So what do you do with that kind of news? I started with my dentist. He gave me a referral to an expert dental surgeon. It practically goes without saying that this surgeon has a waiting list. They told me it would take eight months, but actually by the time I see him a year will have passed.
In the meantime I saw another dentist who used to be a surgeon. He said that my function is better than he would have thought from the scan. Since the jaw joint deteriorates slowly over the years it can adjust to gradual changes and using a night guard for protection would likely be helpful. He also advised me not to eat apples or other large fruits or big sandwiches on hard crusty buns.
Can't eat this apple no matter what happens
Two RA friends with jaw trouble have had special physiotherapy. Tense muscles contributed to their problems and now they can at least open their mouths wider. Another friend with pain issues was seen recently in group therapy at a pain clinic. Half of the people in her group had jaw problems, so it's a piece of luck that so far I don't see that happening.
My jaw does cause problems. The worst happen after a day in meetings or at a conference. All of that extra stress and extra smiling makes my jaw sore enough to cause pain and headaches.
You'd think smiling would not put you in the penalty box
TMJ Disorders - NIH
Merck Manuals TMJ