Temporomandibular Joint Dysfunction

Temporomandibular disorders (TMDs) are a heterogeneous collection of disorders characterized by orofacial pain and/or masticatory dysfunction. TMDs are more commonly reported by women, typically in their 30s, than by men. A dual-axis diagnostic system utilizes both physical examination procedures and assessment of a patient's psychological state. The National Institutes of Health strongly recommends conservative, reversible treatments for TMDs.

The pain reported by TMD patients is typically located in the muscles of mastication, in the preauricular area, or in the temporomandibular joint (TMJ). TMD patients may also report headache, other facial pains, earache, dizziness, ringing in the ears, and neck, shoulder, and back pain. TMD patients may report a variety of TMJ problems other than pain, including locking in the open or closed position, and TMJ clicking, popping, and grating sounds. Patients may report difficulty opening their jaws wide as well as a sense that their occlusion feels “off.” The spectrum of symptoms leads patients to seek care from dentists, physicians, and other health professionals.

The prevalence of TMD varies by age and gender. Unlike many joint-related conditions, TMD is more prevalent in those under age 45. The prevalence ratio for females versus males is approximately 2:1 when nonclinic populations are assessed. However, the ratio can be as high as 8:1 in patient samples. Prevalence rates of TMD vary dramatically, depending on the definition of the condition. Estimates suggest that 4.5 percent of the adult population report pain and dysfunction sufficiently severe to prompt help seeking.

Most cases of TMD involve either muscle pain, problems with the articular disc of the TMJ, degenerative changes in the TMJ, or a combination of these. The most widely researched and best validated system for assessing TMD is based on the Research Diagnostic Criteria (RDC) for TMD. This is a dual-axis system assessing physical disorders on Axis I and self-reported pain, disability, and psychological symptoms on Axis II. For Axis I, patients may receive a diagnosis of myofascial pain, one of several forms of disc displacement, and/or a diagnosis referring to joint problems. Axis II evaluation provides information on current pain levels, disability, depression, and somatization and may be helpful with treatment planning.

The National Institute of Dental and Craniofacial Research strongly recommends conservative, reversible treatments for patients with TMD. Among these treatments are interocclusal appliances, medications, self-care strategies, physical therapy, and behavioral interventions. Interocclusal appliances are also known as mouth guards or “splints.” The most commonly used interocclusal appliances are fabricated from hard acrylic, placed on either the mandibular or maxillary teeth, and cover the occlusal surfaces of all the teeth. The occlusal side of the [Page 1653]appliance typically presents a relatively flat surface to the opposing teeth. Interocclusal appliances can also be fabricated from softer materials, cover only a portion of the teeth, and maintain the jaw in a fixed position. There is general consensus that splints reduce TMD pain, although the mechanism of action is unknown.

Clinicians frequently use nonsteroidal antiinflammatories to reduce pain in TMD patients; low-dose regimens or tricyclic anti-depressants may also reduce pain in select patients. Self-care regimens involve the use of hot/cold packs for controlling pain, identifying and avoiding triggers for pain (e.g., hard, chewy foods), and avoiding unnecessary behaviors involving the jaw (e.g., biting fingernails). Physical therapy exercises emphasize gentle stretching exercises performed at home. The psychological interventions show considerable promise in the treatment of TMD pain. Many of these programs use cognitive-behavioral techniques, often combined with biofeedback, to manage pain, and they show good long-term results.

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