Hi Rachael!
I just wrote a massive post about everything but my browser crashed arggggghhhh! I'll see if I can remember everything I wrote
I used to wear a night guard that my general dentist made for me to protect my teeth from grinding but not to help my jaw. Is this the kind of guard you have?
I'm in Australia and just googled 'neuromuscular dentist' to find one near me (not a lot of them around so I was lucky to find one nearby!). The place I go to is
http://lifetimesmiles.com.au/ . There's great info on the site (the neuromuscular dentistry and TMJ links inparticular) and details of my dentist's qualifications so you can see how he might compare with the options you have over there.
I didn't need a referral to the dentist here but after my initial assessment which showed I do have all sorts of jaw problems, I got a referral from my family doctor so I could get goverment help with the costs.
I've already had a great improvement with my the pain in my actual jaw joints but my neck is still a bit painful - early days! I think sleeping is a problem as my jaw just flops into different positions depending on how i'm sleeping thanks to gravity and laxity (my nemeses!), so I think my dentist is going to create something to help keep my jaw in position while I sleep (he's an inventive chap which is brilliant for unusual cases like us).
I'll keep you posted on my progress - I have my next appointment next week so I'll let you know if anything of interest happens
I hope you find someone who can help you! I've found the TMJ, TMJ Worldwide, and Ehlers Danlos Syndrome facebook groups/pages to be informative too if you're on facebook.
Let me know if you have any more questions

Gentle hugs
