Is an umbrella term covering pain and dysfunction of the muscles of mastication (the muscles that move the jaw) and the temporomandibular joints (the joints that connect the mandible to the skull). The most important feature is pain, followed by restricted mandibular movement, and noises from the temporomandibular joints (TMJ) during jaw movement. Although TMD is not life-threatening, it can be detrimental to the quality of life, because the symptoms can become chronic and difficult to manage. TMD is thought to be very common; it is the most frequent cause of orofacial pain after dental pain (i.e. toothache). About 20-30% of the adult population is affected to some degree. Some patients can start having TMD symptoms as early as 7 years old. The symptoms tend to get worse over time, and it is more common in females than males (85% of TMD patients are female).
TMD consists of many symptoms rather than a single symptom, and it is thought to be caused by multiple factors.