I asked my dentist about TMJD and while he had heard of it, he was only really able to recommend a bite guard to stop me grinding at night - a cause of TMJD too so I read. I think dentists are kind of like GPs, they have a broad understanding but not the level of expertise that you need to deal with it. I also spoke to the guy who removed my wisdom tooth (a maxillofacial surgeon) and he stated bluntly that there was no relationship whatsoever between the jaw and the ears!
However, I am seeing a physio (my long term wisdom tooth problem has left me with a painful jaw even though it has now been removed) and she is really big on TMD etc. She reckons it is all about posture - even though your bite and jaw joint might be physically OK, the jaw moves very differently depending on the position of your head (I guess as gravity comes into play). She made me tilt my head all the way to the left and right and bite down - the teeth made contact at different sides depending on the direction you tilt your head. Thus, according to her, the muscles get strained (both jaw and neck) if you're slouching and your head is in the wrong position. She reckons it is all about muscles and nerves. Nail biting, pen chewing etc. can all be factors behind it too plus all the unconscious things you do - I realised that I tended to bite my lower lip a bit - never knew I was doing it till she pointed it out. My jaw joint was fine, but the muscles were either very weak or incredibly tight. She said my swallow reflex was all wrong too and I'm working on that.
It is difficult as there are several disciplines who will claim to help. As far as I understand, a dentist can help with your bite (filing teeth down, removing protruding wisdom teeth etc.) and trying to stop you grinding. A maxillofacial surgeon can operate to rectify a damaged jaw joint. A "neuromuscular dentist" (whatever that is) can apparantly help you with laser alignment of your jaw etc. (bit dubious that I reckon) but a good physio can help your body move the way it was designed to do. I have a very different posture now and according to her use a different set (the correct set!) of muscles to move my head. I still find myself slouching and holding my head forward but at least I am aware of it now. I used to sit with the seat reclined at work which made me hold my head forward a bit, but now I sit upright like an elderly woman driving (!) and it is more comfortable. Playing havoc with the flare - my excuse - sticking to it
I get a bit of tinnitus too - I always thought it was due to me going to concerts etc. as a student and noise on the ramp, but she reckons it is partly due to the jaw trouble as the joint is really close to your tubes.
I also get a bit of exczema - still there but better since I cut out dairy. I also drink more water now (being hydrated can help thin out the mucus a wee bit.)
Have you tried nasal and sinus irrigation with salt water? I know this sound a bit odd but it crops up time and time again when you're searching for this kind of advice. I guess it works by cleaning out the nasal passageways - important I suppose as the end of the ET is up there.