Temporomandibular disorders: Etiology and classification

Temporomandibular disorders (TMDs) are a group of disorders that have their origin in the musculoskeletal structures of the masticatory system [1]. Therefore, symptoms of TMDs are associated with either the muscles of mastication or the temporomandibular joints (TMJs), or both. Pain can be a common symptom associated with TMDs. These disorders are quite common in the general population. In fact, after dental pains, TMDs are the next most common pain complaint reported by patients in the dental office. Depending on which epidemiologic studies are reviewed the numbers of signs and symptoms associated with TMDs range from 40 % and 60 % of the general population [2, p. 102-28]. However, the numbers of patients requiring professional TMD treatment are reported to be only in the range of 10-15 % [3, 4]. Because TMDs are so common, every dentist needs to have a basic understanding of the etiology, diagnosis, and management of these conditions. This chapter will focus on the etiology and diagnosis of the most common TMD conditions seen in the dental office. Other texts should be reviewed for a more complete overview [2].