True pathologic derangement of the TMJ as the isolated cause for pain is not common. TMJ damage can be the result of direct trauma, wear and tear from chronic pathologic occlusal forces, and overextension of jaw movements. Some other conditions also affect the TMJ, such as congenital and developmental disorders (e.g., hyperplasia and neoplasia), inflammatory disorders (e.g., arthritis), osteoarthritis, and ankylosis. Just as one can find magnetic resonance imaging (MRI) abnormalities of the lumbar spine in patients who are asymptomatic, so can one find evident TMJ pathology in asymptomatic individuals. Many subjects have an “abnormal” TMJ, which “clicks” or has a deviation or displacement during opening and closing of the mandible, but few have accompanying pain. However, if the patient complains of a chronic TMJ dysfunction with pain, he/she deserves assessment by an orofacial pain specialist.

TM muscle disorder is characterized by dull aching pain exacerbated by mandibular function, muscle tenderness in one or more masticatory muscles, and often a decreased mandibular range of motion. The pain is commonly described as a dull ache exacerbated by chewing, fluctuating in intensity daily, and associated with remissions lasting months. A range of terms exist, with a variety of classifications and subclassifications. These classifications include myofascial dysfunction, myositis, myalgia, myospasm, and myofibrotic contracture. The absence of clinical features referable to the TMJ and the presence of muscle tenderness distinguish this from primary TMJ articular disorders, although secondary TMJ changes and joint remodeling can occur.

Dysfunction of the muscles of the shoulders, neck, head, and face is relatively common in the general population and can aggravate headaches, sinus area pain, and orofacial pain. Fibromyalgia is a type of myofascial dysfunction distinguished as a systemic disease characterized by muscle pain and tenderness in multiple body quadrants. It can be exacerbated by stress, anxiety, and weather changes, and accompanied by a variety of generalized symptoms such as fatigue, morning stiffness, and headache. The patient with fibromyalgia may initially present with facial pain and tenderness in the muscles of mastication; it is important to question patients for systemic features and not focus simply on the local complaint. Other systemic myofascial disorders are polymyalgia, lupus erythematosus, polymyositis, and dermatomyosits. A more common complaint of generalized pain, although usually limited to the upper quadrant of the body, is the direct trauma and whiplash injury to muscles of the neck and shoulders.

A patient diagnosed with TM disorders may benefit from complete evaluation and treatment by a physical therapist. The treatment program may include stretching, strengthening, and endurance exercises, transcutaneous electrical nerve stimulation (TENS), ultrasound, thermal application, and mobilization (joint and soft tissue). The patient should follow an active exercise program at home with guidance from a physical therapist.

Pharmacologic therapy includes judicious use of nonsteroidal antiinflammatory drugs (NSAIDs), very selective use of tricyclic antidepressants (TCAs), and selective use of anticonvulsants, other analgesics, muscle relaxants, anxiolytics, and, very rarely, opioids. NSAIDs may be used for both their analgesic and antiinflammatory properties. There is marked interpatient variability in response to different agents, necessitating trials of agents until the optimal response is obtained. Because of the ceiling effect of NSAIDs and gastrointestinal and renal toxicity issues, increasing doses, and time of use beyond the recommended maximum is not useful. NSAIDs are of no proven value in the long-term management of TMJ pain, although large doses may provide short-term relief. Patients who are unable to tolerate NSAIDs may use tramadol hydrochloride, a weak and nonaddicting μ-agonist, at a dosage of 50 to 100 mg
every 6 hours, as needed. Short-term use of centrally acting muscle relaxants includes cyclobenzapine (Flexeril) and carisoprodol (Soma). These agents decrease excess electromyogram (EMG) activity and muscle spasm. The tertiary amine amitriptyline, having greater anticholinergic effects than the secondary amines desipramine and nortriptyline, in low doses, may improve sleep and may act as indirect analgesics by inhibiting serotonin and norepinephrine reuptake. Benzodiazepines, such as diazepam, decrease muscle spasm, improve sleep, and show anxiolytic activity. A dosage of 0.5 mg once or twice a day is useful in initial therapy. Prolonged use of benzodiazepines should be avoided because of their addiction potential. In patients requiring prolonged treatment of anxiety symptoms, buspirone (Buspar) 5 mg three times daily is effective with little addiction potential, but has no muscle relaxant effects.

Pressure on active trigger points (TPs) causes acute pain, and produces spasms when the muscle is used, decreasing the range of motion. Trigger points can be localized by pressure and then inactivated by the topical application of vapocoolant spray (dichlorodifluoromethane), allowing stretching exercises to restore muscle mobility. The injection of local anesthetics in the TP can be performed with subsequent physical therapy. This injection provides prolonged analgesia, allowing the patient a pain-free period to commence physical therapy, with subsequent use of vapocoolants and stretching exercises at home. However, the pain relief may last much longer than the anesthetic effect. Corticosteroids, such as triamcinolone acetonide (Kenalog) can be added to the mixture. Steroid injections should not be repeated any sooner than six weeks, as a peau d’orange cosmetic defect may occur.

Botulinum toxin (BTX) injection is proven to be an excellent therapeutic tool for the treatment of myofascial pain. First indicated for involuntary muscle contraction disorders (e.g., blepharospasm and dystonia), BTX seems to disrupt the membrane- fusion and exocytosis of acetylcholine-containing vesicles into the extracellular milieu. The effects are reduction of muscular tone, contractility, and graded chemical denervation in the muscular area injected. Botulinum toxin may also reduce pain, and clinical reports support its use in some chronic pain diseases, including primary headaches (e.g., tension-type headache), inflammatory pain, and even some selected cases of trigeminal, and postsurgical and posttraumatic neuropathic pain. It appears that more injections with lower units per injection over an area of pain are more effective than a single large dose injection. However, randomized control clinical studies are lacking. The beneficial effect of a BTX injection can last for an average of 4 months and may be repeated if indicated. Advantages include no systemic side effects, but the application requires a practitioner skilled in the use of BTX in the head and neck, to avoid unanticipated facial and other head and neck muscular weakness, transient facial deformity, or severe respiratory, masticatory, and swallowing compromise.

Psychologic intervention including biofeedback, relaxation techniques, and cognitive behavioral
therapy addressing aversive behaviors when they exist should be considered.

Advocates of splint therapy suggest that it temporarily equilibrates bite occlusion, mechanically unloading the TMJ and limiting masticatory muscle activity, thereby decreasing symptoms of TM disorders. Occlusal appliance therapy seems to be beneficial in cases of myofascial pain, even when there are no signs of parafunctional habits (e.g., bruxism). Missing teeth and dental malocclusions have an inconsistent relation to TM disorders. In extreme occlusal discrepancies, oral rehabilitation (e.g., orthodontic and prosthodontic treatments) may improve masticatory function, without guarantee of pain relief.

Open surgery of the TMJ is associated with high morbidity and a lack of efficacy, unless proper and careful patient selection is utilized by an experienced oral and maxillofacial surgeon. More conservative procedures, such as arthrocenthesis and arthroscopic surgeries, should be considered first.

Temporary rest of the TMJ is sometimes helpful. Liquid and soft diet is instituted, and gum chewing is stopped. Wide, uncontrolled opening of the jaw is discouraged. Yawning, coughing, laughing, and the eating of large sandwiches are kept to a minimum. A hand or fist placed under the chin during wide mouth opening helps to hold the jaw in place. Heat or ice gel pack therapy can be useful; a heating pad, warm face cloth, or warm water bottle placed to the sides of the jaw and TMJ area will have a soothing and relaxing effect on the muscles. Alternatively, an ice gel pack for 10 to 20 minutes should be tried. Gentle midline opening and closing exercises of the mandible help retrain and relax muscles. Use of a vapocoolant spray also may be helpful in reducing movement-induced pain, so that exercises designed to improve joint mobility can be tolerated. Judicious use of NSAIDs may also help. Consider acetaminophen in patients with NSAID sensitivity, or coxibs in patients with a serious risk for bleeding or other relevant history.