Neuromuscular problems in the orofacial region: aetiology and organic pathology.

Psychological factors play a significant role in the aetiology of functional disorders of the masticatory system but the pain-dysfunction symptoms can mostly be explained with musculoskeletal tissue changes. In the jaw muscles inflammatory responses are frequently caused by muscular hyperactivity. The temporomandibular joint may be affected by many diseases of which osteoarthrosis is probably the most common. A pathologic process in the temporomandibular joint proper is often a cause of pain and dysfunction of the masticatory system, and this may be true even without radiographic evidence of structural changes.