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Abstract
The temporomandibular joint (TMJ) is decisive for normal jaw function such as chewing, swallowing, speaking, oral health, and nutrition. Temporomandibular disorders (TMDs) refer to a group of disorders affecting the TMJ, masticatory muscles, and the associated structures. TMDs are considered as a multifactorial disorder. These conditions have been unable to reveal a common etiology or biological basis in terms of apparent signs and symptoms, and hence considered a heterogeneous group of health problems associated with chronic pain. These disorders share the symptoms of pain, limited mouth opening, and joint noises. The causes of TMDs range from traumatic injury to immune-mediated systemic disease to neoplastic growth to incompletely understood neurobiological mechanisms. This article presents an overview of the various etiological factors, signs, and symptoms related to TMDs.
Keywords
Clinical features, etiology, temporomandibular disorders, temporomandibular joint
Introduction
Temporomandibular joint (TMJ) is a unique joint in which translatory as well as rotational movements are possible and where both ends of bone articulate in the same plane with that of other bone. It is also called as ginglymoarthrodial type of joint wherein it has sliding movement between bony surfaces in addition to hinge movement similar to diarthroidial joint.[1] Temporomandibular disorders (TMDs) are defined by the American Academy of Orofacial Pain as "a collective term that embraces a number of clinical problems that involve the masticatory muscles, the TMJ and the associated structures." Its key characteristics are pain in the TMJ and surrounding tissues; dysfunction, clicking and locking of the mandible. The signs and symptoms of TMD are experienced by up to 60% of the general population at some stage in their life occurring across all ages and gender.[2] Commonly patients present first to their dentist for initial management.
Etiology
TMDs have multiple etiological factors. Many studies show a poor correlation between any single etiological factor and resulting signs and symptoms.[3] In fact, the TMJ and masticatory system are complex, and thus, requires a thorough understanding of the anatomy and physiology of the structural, vascular and neurological components to manage TMD. Alterations in any one or a combination of teeth periodontal ligament, the TMJ, or the muscles of mastication eventually can lead to TMD. Etiologic factors contributing to the development of TMD are as the following section.
Trauma