Temporomandibular myofascial pain syndrome (previously known as myofascial pain and dysfunction syndrome [MPDS or MFPDS]) can occur in patients with a normal temporomandibular joint. It is caused by muscle tension, fatigue, or (rarely) spasm in the masticatory muscles. Symptoms include pain and tenderness in and around the masticatory structures or referred to other locations in the head and neck, and, often, abnormalities of jaw mobility. Diagnosis is based on history and physical examination. Conservative treatment, including analgesics, muscle relaxation, modification of parafunctional behavior (eg, teeth clenching and grinding), and use of oral appliances usually is effective.
(See also Overview of Temporomandibular Disorders.)
This condition is the most common disorder affecting the temporomandibular region. It is more common among women and has a bimodal age distribution in the early 20s and around menopause.
In the affected muscle, both pain and trigger points (which cause referred pain) may result from parafunctional behavior such as bruxism (clenching or grinding of the teeth), which is regarded as 2 distinct entities: sleep or awake bruxism, which have different etiologies.
Temporomandibular myofascial pain syndrome is not limited to the muscles of mastication. It can occur anywhere in the body, most commonly involving muscles in the neck, shoulders, and back.
Symptoms and Signs of Temporomandibular Myofascial Pain Syndrome
Symptoms include pain and tenderness of the masticatory muscles and often pain and limitation of jaw excursion. Both sleep bruxism and sleep-disordered breathing (such as obstructive sleep apnea and upper airway resistance syndrome) are associated with headache that is more severe on awakening and gradually subsides during the day. Such pain must be distinguished from the pain caused by giant cell arteritis. Awake symptoms, including jaw muscle fatigue, jaw pain, and headaches, usually worsen if parafunctional behavior continues throughout the day.
The jaw deviates when the mouth opens but usually not as suddenly or always at the same point of opening as it does with internal temporomandibular joint derangement. Exerting gentle pressure on the lower anterior teeth, the examiner can stretch the involved muscles and thereby assist the patient in opening the mouth another 1 to 3 mm beyond unaided maximum opening.
Diagnosis of Temporomandibular Myofascial Pain Syndrome
Clinical evaluation
Sometimes polysomnography
A simple test may aid the diagnosis: 2 or 3 tongue blades are placed between the rearmost molars on each side, and the patient is asked to close the mouth gently (1, 2, 3). The distraction produced in the joint space may ease the symptoms. X-rays usually do not help, except to rule out arthritis. If giant cell arteritis is suspected, erythrocyte sedimentation rate (ESR) is measured.
Polysomnography should be done if sleep-disordered breathing is suspected.
Diagnosis references
1. Schiffman E, Ohrbach R, Truelove E, et al: Diagnostic criteria for temporomandibular disorders (DC/TMD) for clinical and research applications: Recommendations of the International RDC/TMD Consortium Network and Orofacial Pain Special Interest Group. J Oral Facial Pain Headache 28(1):6-27, 2014. doi: 10.11607/jop.1151
2. Peck C, Goulet J-P, Lobbezoo F, et al: Expanding the taxonomy of the diagnostic criteria for temporomandibular disorders. J Oral Rehabil 41(1):2-23, 2014. doi: 10.1111/joor.12132
3. International Classification of Orofacial Pain, 1st edition (ICOP).Cephalalgia 40(2):129-221, 2020. doi: 10.1177/0333102419893823
Treatment of Temporomandibular Myofascial Pain Syndrome
Mild analgesics
Oral appliances
Trigger point injections and other physical and behavioral therapy modalities
An oral appliance from a dentist can keep teeth from contacting each other and thereby reduce the damage caused by bruxism. Over-the-counter heat-moldable (boil and bite) mouth guards are available from many sporting goods stores or drugstores; however, these types of devices should be used briefly and only as short-term diagnostic tools. Because these mouth guards may cause unwanted tooth movement or create a paradoxical increase in muscle activity, oral appliances should ideally be fabricated, fitted, and adjusted by a dentist.
The patient must learn to stop parafunctional behavior (eg, clenching the jaw, grinding the teeth) when awake. Hard-to-chew foods and chewing gum should be avoided. Physical therapy, biofeedback to encourage relaxation, and counseling help some patients.
Physical modalities include trigger point injections, transcutaneous electric nerve stimulation
Most patients, even if untreated, customarily have diminished or cessation of significant symptoms within 6 to 12 months.
Key Points
Temporomandibular myofascial pain syndrome is a more common cause of temporomandibular pain than temporomandibular joint derangement.
Tension, fatigue, and (rarely) spasm of the masticatory muscles may result from parafunctional behavior (eg, bruxism).
Patients have pain and tenderness of the masticatory muscles, painful limitation of jaw excursion, and sometimes headache.
Use of oral appliances, benzodiazepines or muscle relaxant during sleep may help, along with nonopioid analgesics; behavioral modalities and physical therapy are sometimes appropriate.
