Temporomandibular Disorders (TMD) are a common subgroup of pain disorders, often referred to as "TMJ". TMJ is the commonly used abbreviation for the temporomandibular joint, or jaw joint. There are two basic types of temporomandibular disorders: muscle-generated pain, and jaw joint-generated pain.

TMD symptoms include pain or discomfort in or around the ear, jaw joint, muscles of the jaw, face, temple, head, neck, and shoulders, as well as teeth, on one or both sides. The pain may arise suddenly or progress over months to years with intermittent frequency and intensity. Clicking, popping, grating (crepitus), locking, limited or deviant jaw opening and chewing difficulties are also associated with TMD.

Muscle-related TMD usually results from overwork, such as grinding or clenching of teeth, fatigue, or tension of the jaw and supporting muscles. Muscle pain may be manifested as a toothache or bone pain.

Joint-related TMD usually results from inflammation, disease, or degeneration of the hard or soft tissues within the TMJ. Inflammation, disc dislocation, and degenerative arthritis are the most common disorders of this type of the TMJ.

Causes of TMD

Causes of TMD are unclear, as it usually involves more than one symptom and rarely has a single cause. TMD is believed to result from several factors acting together, including jaw injuries (trauma), joint disease (arthritis), tooth clenching/grinding (bruxism), and head and neck muscle tension. While not scientifically proven to be a cause of TMD, stress may perpetuate TMD symptoms and often needs to be controlled to reduce and manage TMD. Stress is analogous to pouring gasoline onto a smoldering fire.

It is important for TMD sufferers to understand that the disorder can be chronic, and highly dependent upon multiple factors, including stress. Because there is no quick fix or immediate cure for TMD, the most successful and scientifically supported treatments focus on self management (lifestyle issues such as smoking and sleep hygiene) and control of perpetuating factors (clenching, bruxism) in concert with medications, physical therapy, and intraoral devices if needed.

(See also Other Types of Orofacial Pain)

* Information provided from portions of the American Academy of Orofacial Pain publication for patients: TMD brochure.