Acupuncture: New Approach for Temporomandibular Disorders
Temporomandibular disorder (TMD) is clinically characterized by pain in the masticatory muscles of the temporomandibular joint (TMJ). This affects an estimated 10 million Americans, and one-third of adults will experience symptoms of TMD over their life span.1,2
Myofascial pain is characterized by localized hypersensitive spots in palpable taut muscle fibers (myofascial trigger points). These trigger points may result from muscle overload from trauma or repetitive activities that cause abnormal stress on specific muscle groups. Clinically, patients complain of tenderness, headaches, restricted movement of the jaws, muscle stiffness, and weakness.
Although millions of Americans use acupuncture each year, often for chronic pain, there has been considerable controversy surrounding its value as a therapy and whether it is anything more than placebo.3 However, research of traditional Chinese medicine revealed that acupuncture is effective in the treatment for temporomandibular disorders and myofascial pain.4-8
How it Works
Although the exact mechanism by which acupuncture may relieve TMD pain is not entirely understood, according to ancient theories of traditional Chinese medicine, acupuncture acts by restoring the balanced flow of Qi, or energy.
Modern research has revealed scientific reasons why acupuncture is a successful therapy. In the 1970s, reports appeared in Western medical literature suggesting that acupuncture reduces pain sensation through direct stimulation of the nerve, which changes the quality of signaling along nerve cells.
In fact, research suggests that acupuncture may suppress the nociceptive trigeminal nucleus caudalis and spinal dorsal horn neurons via modulation of the release of neuropeptides and neurotransmitters.9,10
Further studies support this idea that acupuncture directly stimulates the release of endorphins and neurotransmitters, among other biological actions. These are naturally occurring substances that help dampen and block pain perception by the brain. Additional research is needed to further study the mechanisms behind acupuncture since many of acupuncture’s effects can still not be explained by either of these medical theories.
Whether by affecting Qi or biological chemicals, what may be more important is simply the evidence that it does work. According to the National Center for Complementary and Integrative Health (NCCIH), “results from a number of studies suggest that acupuncture may help ease chronic low-back pain, neck pain, and osteoarthritis/knee pain. It also may help reduce the frequency of tension headaches and prevent migraine headaches.”3
Measuring the effectiveness of acupuncture is only beginning to be understood. “Current evidence suggests that many factors—like expectation and belief—that are unrelated to acupuncture needling may play important roles in the beneficial effects of acupuncture on pain,” noted NCCIH.
Acupuncture and TMD
Acupuncture is frequently used to treat TMD and TMJ with positive results.6 As a long-standing treatment approach, research has determined the recommended acupuncture points (Table 1), frequency (weekly), and duration (30 minutes per session) of acupuncture treatment for TMD-related problems. In treating TMD, acupuncturists often find a deficiency in Qi in the liver (LV) meridian and an excess of Qi in the gallbladder (GB) meridian.11
Needles may be inserted in the area of the pain, around the ear and the jaw. However, because of the interconnecting pathways between the meridians, the needles may be inserted near the elbows, knees, and big toe. These distal locations can alter the flow of Qi through the jaw to relieve pain and inflammation as well. Additional acupuncture points are to address other disharmonies detected in the body. Correcting the overall flow of energy in the body can help relieve stress and other possible contributing factors to TMJ disorder.12
Several clinical studies demonstrated the validity of acupuncture as an effective therapeutic intervention for head and facial pain.13,14 While acupuncture therapy may not eliminate the cause of TMD resulting from structural anomalies, such as degenerative changes and disc displacement, acupuncture can help relieve the pain and discomfort associated with the conditions. It has been documented that acupuncture can help muscle relaxation and reduce muscle spasms, if the spasms are muscular in origin.15 Acupuncture can also help minimize TMJ “clicking” by relaxing the lateral pterygoid muscles, and therby reducing the anterior displacing force on the meniscus of the TMJ.16
In a 2007 study, TMJ-related short-term muscle pain was significantly improved in people receiving acupuncture.17 A recent British study of 70 cases of dental patients receiving acupuncture for TMJ indicated that 85% of patients benefited with an average reduction in pain intensity of 75%.18 A 2008 study reported long-term high patient satisfaction and improvement of symptoms 18 to 20 years following acupuncture and/or interocclusal appliance (bite plate or splint) therapy.19
Studies of its application to TMD show acupuncture comparable to more conventional treatments.20,21 Very credible evidence from the University of Maryland Medical Center suggests that acupuncture can treat TMJ dysfunction.11 In addition, research by Park et al and Shen et al revealed the effectiveness of acupuncture in the treatment of myofascial pain.7,8
In 2012, researchers conducted the study in 2 pain clinics in Tucson, Arizona, and Portland, Oregon.22 They enrolled 168 adults with TMD. Initially, all patients attended a 2-hour class on TMD. At week 2, the researchers assigned patients with the worst TMD pain (above a predetermined level) either to a traditional Chinese medicine or self-care group. The traditional Chinese medicine intervention (consisting of up to 20 visits within 1 year) was tailored to the patient and could include acupuncture, Chinese herbs, massage, and lifestyle counseling. The self-care intervention included patient education, jaw stretching exercises, training in relaxation and stress management, and cognitive behavioral therapy. Participants in the self-care group also received a self-help manual.
The researchers found that traditional Chinese medicine provided significantly greater short-term pain relief than self-care, as well as greater reduction in interference with social activities. They concluded that this kind of stepped-care, community-based approach using traditional Chinese medicine is safe and could offer short-term relief of pain and improved quality of life for patients with TMD. The long-term outcomes of this study are forthcoming and will provide a more complete picture of the impact of this treatment strategy.22 Combined Therapies