Well, I've just started wearing a mouth guard at night for my TMJ issue, and so far so good. I've worn it for three nights and already I'm noticing that the painful popping on my left jaw has gone away. There's still some general pain there, especially when I open my mouth wide to yawn (I'm trying so hard not to do that!), and when I'm chewing. But, it's a little better. I'm hopeful that this will really help. It better, anyway. The mouth guard wasn't covered by insurance, naturally, and cost $800.
I haven't tackled the root cause of the TMJ, which is most likely the stress I've been under lately, but that's next on my agenda.......