Can TENS therapy (transcutaneous electrical nerve stimulation) help relieve my TMD (temporomandibular joint disorder)? My dentist suggested it.
There’s some preliminary evidence it could. TMD involves the temporomandibular joint located on each side of the face that allows you to move your jaw to speak and chew. This painful condition occurs when the joint is not working properly or the surrounding muscles or ligaments are tight or inflamed. Many factors—such as bruxism (where you clench or grind your teeth), an injury to your jaw, a problem with your bite, or arthritis of this joint—can cause or exacerbate TMD. By some estimates, about one-third of the U.S. population has at least one TMD symptom, and up to 7 percent have it severe enough to want treatment.
TENS, commonly called electro-stim, can be done by a dentist or skilled physical therapist. Small, sticky pads are placed on the jaw area, and these are connected by wires to a device that administers a low electrical current, usually in a pulsating manner, for a certain amount of time and at a certain frequency. You can purchase a TENS machine online or at a pharmacy, but it’s best to get professional treatment first. That way, you can learn how to do it properly, including where to place the electrodes and what frequency to set the device at, as well as how often and how long to use it.
But does TENS work? Several studies have looked at its immediate effects. For instance, in a 2020 study in the Journal of Clinical Medicine, 36 people who had muscle pain due to TMD and 39 people without TMD received a single 20-minute TENS session. After the session, the TENS group had reduced pain and could open their mouths wider than before, while both groups had increases in the amount of force they could exert when biting. The authors concluded that “TENS treatment might quickly relieve pain in masticatory muscles and improve masticatory system functions in patients with TMD-related muscle pain”—although the study would have been more meaningful if there had been a true control group of people with TMD who received sham TENS treatment.
A 2019 systematic review of 14 studies (six with control groups) that included a total of 285 people with TMD found that a single session of TENS relieved pain (anywhere from 19 to 77 percent) and improved joint functioning (ranging from about 9 to 19 percent)—on par with results from other treatments (laser and ultrasound).
At least one study, from 2017, involved multiple TENS sessions. Forty-five people with TMD received eight sessions of either TENS or low-level laser therapy over two weeks. Both groups experienced improvements in pain, muscle tenderness, and joint functioning, with TENS providing more rapid and longer-lasting pain reduction. The authors concluded that both these modalities are effective in people with TMD and can be used as an adjunct treatment. But there was no control group to assess whether the improvements were due to any placebo effect.
In addition to studies generally being small and short in duration—and sometimes lacking control groups—another problem is that there has been great variability in the types of TENS sessions used in trials, including how long and how frequently the treatment was administered as well as whether the frequency was high or low. There’s also variability in the types of TMD the subjects present with—for some people the primary problem is with the muscles, while others have joint dysfunction, and it’s unclear whether the benefits from TENS differ depending on this.
BOTTOM LINE: Despite the need for better, bigger, and longer studies, TENS is still worth a try since it’s safe and noninvasive. It won’t hurt (assuming you have no open wounds or skin irritation where the electrodes would be placed or any allergies to substances in the pads)—and may help. Insurance may cover it when it’s done by a dentist or physical therapist. If you prefer to continue on your own after getting professional treatment, your provider may be able to recommend a TENS device suitable for you. They range in price from about $50 to $300.
Other treatment modalities that can be used in combination with TENS include mouthguards (if the cause of TMD is bruxism), hot or cold compresses, relaxation techniques and stress management, therapies like acupuncture and biofeedback, physical therapy, and drug therapy, all of which have varying degrees of evidence to back them. A physical therapist experienced in treating TMD can do manual therapy (such as massage or trigger-point therapy) or teach you postural exercises of the head and neck and specific neck and jaw exercises to help relieve symptoms. Don’t attempt exercises on your own initially—the temporomandibular joint and associated muscles and ligaments are complex, and if you indiscriminately stretch or exercise them, you could make things worse.
