I looked around but couldn’t find any specific imagery that targets TMJ. But any sort of stress reduction or progressive muscle relaxation program would be good, of course.
And I would also recommend our audio for Healthful Sleep. Even though it doesn’t address TMJ specifically, it involves relaxing and softening all the muscles of the face (including the jaw), and the rest of the body too, along with many other images of protection and safety. People tell us they not only sleep better and with greater relaxation, but wake up with a more positive feeling, too.
And you’re right - it’s a very good idea to listen to an imagery audio while you’re falling asleep - not only because this is when your jaw is doing most of its clenching and grinding; but because falling asleep is one of our most receptive times to take in healing imagery of any kind, because our brain waves are slowing down and our right hemisphere is more active... a very spongey time indeed to soak up some positive imagery! Give it a try and let me know how you do.
I did find some other general recommendations for TMJ here - maybe you’ll find something new and useful on this list of suggestions.
Best of luck,