It can be effective, but if the dentist uses this technique exclusively I would be cautious.
In my opinion, muscle tension is a result of disc displacements
in the TMJ and there are many other complicating factors that should not be overlooked. When dentists buy the necessary technology to do NM dentistry they take training to go with it. That training alone is not adequate to treat all the the TMJ problems out there. This has been my experience.