My recent emergency, was that my jaw muscles clamped shut so hard that I shattered another tooth. I needed to get surgery done by a proper oral surgeon (not just a dentist). It was difficult for the surgeon to take all the broken pieces of tooth out of my gums. Thankfully, he got it done. I am very grateful.
At the moment, my jaw muscle tension remains, and it is quite sore all the time. If I'm not actively trying to keep my mouth open, then it clamps shut really hard, even while I'm awake. (So although something like a nightguard might help, it wouldn't actually be a solution.)
Long-term, if unaddressed, this jaw tension will break more of my teeth.
As a long term solution, my doctor's best idea is for me to get botox injections in my jaw muscles, in order to keep them in a weakened state. They would still work, they simply wouldn't be so incredibly strong.
As a temporary solution, short term, I hold a piece of thick cloth as a cushion between my back teeth, on the right side. For now, that's protecting all my teeth, since they can't make direct contact with each other.
ECT was a very effective therapy for pain relief, in myself. Once every six weeks, I used to get it in the hospital, where I was put unconscious under anesthesia, while my body was electrocuted. The treatment's exact method of function has never been something science has understood completely. However, in my case, my best doctor told me that it likely "reset" or "cleaned up" my sodium channels somehow, leading to less neuropathic pain.
Unfortunately, for obvious reasons, electroconvulsive therapy is extremely dangerous. It is essentially a last resort treatment that isn't used until all other options have been exhausted. It can also be very helpful for People with serious depression, but in my case, it actually directly treated the pain itself (Which is why my doctor recommended it.)
Because of this incident, and the other serious side effects of ECT, along with the fact that we found other medications to help, bend that eventually I was able to stop doing ECT altogether. ECT was, for a time, a miraculous treatment for me, But it is quite dangerous, and has severe long term side effects that I still struggle with. I do recommend it, but only in situations of absolute desperation.