The role of occlusion in temporomandibular disorders--a review of the literature.

According to the glossary of prosthodontic terms, temporomandibular disorders (TMD) are defined as: "Conditions producing abnormal, incomplete or impaired function of the temporomandibular joint(s)" or "a collection of symptoms related to the masticatory system, frequently observed in various combinations" (van Blarcom et al., 2005). Others have defined TMD as a collective term, embracing several clinical problems involving the muscles, temporomandibular joint (TMJ), or both (Okeson, 1996). TMDs form a cluster of related disorders with common symptoms which include localised pain, limited or asymmetric movement, and clicks or grating on opening. Unfortunately, there appears to be no consensus regarding the definition of a temporomandibular disorder within the literature (Mohlin and Thilander, 1984; Okeson, 2003a), and there is considerable variation among epidemiological studies. These studies report that between 5 and 50% of individuals experience TMD pain (Dworkin and Massoth, 1994), with females comprising 75% to 84% of those affected (Dworkin et al., 1990). This may be related to differences in pain measurement criteria or study design, and women tending to present for treatment more readily than men. The aim of this article is to review the history of how occlusion became associated with TMD, and the extent of that association in the contemporary scientific literature.