TENS stands for "transcutaneous electrical neural stimulation".
A device called the Myomonitor is used to deliver gentle electrical stimulation to your muscles to help them get into a relaxed state.
The Myomonitor is battery operated device and delivers the pulse through adhesive electrodes attached to the skin over muscle sites and nerves that control specific facial muscle groups.
The myomonitor will cause your facial and jaw muscles to twitch or "pulse" once every 1 1/2 seconds.
Tense muscles suffer from restricted blood flow. As the muscles are "exercised" with electrical stimulation and the muscles begin to relax, blood flow to the muscle increases. This not only brings more oxygen and nutrients to the muscles, but flushes away accumulated waste products of metabolism. Usually after 30-60 minutes, the electrically induced "exercise" will allow your muscles to overcome their habitual programming and go to a state of physiologic rest.
Muscle relaxation can also be an effective relief of pain (ie headaches, neckaches) and this can be an effective means of drug-free pain relief for some patients-but it is temporary because it does not treat the underlying problem-which may be your bite.
That is where the orthotic comes into play.