Pain present for a minimum of 3 months.The International Headache Societys diagnostic criteria for "headache or facial pain attributed to temporomandibular joint disorder" is similar to the above:
A. Recurrent pain in one or more regions of the head or face fulfilling criteria C and D
B. X-ray, MRI or bone scintigraphy demonstrate TMJ disorder
C. Evidence that pain can be attributed to the TMJ disorder, based on at least one of the following:
pain is precipitated by jaw movements or chewing of hard or tough food
reduced range of or irregular jaw opening
noise from one or both TMJs during jaw movements
tenderness of the joint capsule(s) of one or both TMJs
D. Headache resolves within 3 months, and does not recur, after successful treatment of the TMJ disorder

Medical imaging
The advantages brought about by diagnostic imaging mainly lie within diagnosing TMD of articular origin. Additional benefits of imaging the TMJ are as follows:
Assess the integrity of anatomical structures in suspicion of disorders
Staging the extent of any pathology
Monitoring and staging the progress of disease
Determining the effects of treatmentWhen clinical examination alone is unable to bring sufficient detail to ascertain the state of the TMJ, imaging methods can act as an adjuvant to clinical examination in the diagnosis of TMD. Plain radiography
This method of imaging allows the visualisation of the joints mineralised areas, therefore excluding the cartilage and soft tissues. A disadvantage of plain radiography is that images are prone to superimposition from surrounding anatomical structures, thereby complicating radiographic interpretation.
Temporomandibular joint dysfunction (TMD, TMJD) 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 which 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 quality of life; this is because the symptoms can become chronic and difficult to manage. In this article, the term temporomandibular disorder is taken to mean any disorder that affects the temporomandibular joint, and temporomandibular joint dysfunction (here also abbreviated to TMD) is taken to mean symptomatic (e.g. pain, limitation of movement, clicking) dysfunction of the temporomandibular joint. However, there is no single, globally accepted term or definition concerning this topic. TMDs have a range of causes and often co-occur with a number of overlapping medical conditions, including headaches, fibromyalgia, back pain, and irritable bowel. However, these factors are poorly understood, and there is disagreement as to their relative importance. There are many treatments available, although there is a general lack of evidence for any treatment in TMD, and no widely accepted treatment protocol. Common treatments include provision of occlusal splints, psychosocial interventions like cognitive behavioral therapy, physical therapy, and pain medication or others. Most sources agree that no irreversible treatment should be carried out for TMD.About 20% to 30% of the adult population are affected to some degree.