**4.5 Temporomandibular disorders**

Temporomandibular disorder (TMD) is a general expression for pain, discomfort, and dysfunction of the masticatory muscles, the temporomandibular joints (TMJs), or both. TMD is the most common orofacial pain condition excluding dental pain. The main complaints from patients are regional pain in the face and periauricular area, limitations in jaw movement, and noise from the TMJs during jaw movements. Its prevalence is up to 15% in adults and 7% in adolescents. Longterm pain is the most important reason why patients with TMD seek treatment. Psychological disabilities are often associated with TMD. As peripheral mechanisms most likely play a role in the onset of TMD, a detailed muscle examination is recommended. The persistence of pain involves more central factors, such as sensitization of the supra spinal neurons and second-order neurons at the level of the spinal dorsal horn/trigeminal nucleus, imbalanced antinociceptive activity, and strong genetic predisposition, which also is included in DC/TMD. The etiology is multifactorial and still not clearly understood, but several biological and psychosocial risk factors for TMD have been identified. We have several treatment approaches to face temporomandibular disorders, including behavioral therapy, pharmacotherapy, physical therapy, and occlusal appliances. Evaluations indicated that the recently published Diagnostic Criteria for TMD (DC/TMD) are reliable and valid. These criteria cover the most common types of TMD and can be listed as follows.
