I just replied to another message in this forum regarding this device but I think anyone who comes here should know about it. If you aren't familiar with MicroCurrent units they basically increase natural ATP production to the targetted site by up to 500%. They look like TENS units but unlike those units they don't kill the pain which actually prevents your body from healing the problem. Instead increasing your bodies own ability to heal the problem. They're used for soft tissue and TMJ is one issue that's listed as it being able to help. I'm awaiting mine in the mail and plan on using it on a mild case of TMJ I'm going through as well as the real reason I got it which is for my herniated disc.
This article seems to explain it the best from what I've seen