Influence of Unilateral Chewing on the Development of Temporomandibular Disorders: New Paradigm

Abstract The American Academy of Orofacial Pain (AAOP) defines temporomandibular disorders (TMD) as “a generic term thatencompasses numerous clinical problems of both the masticatory muscles and the temporomandibular joints and their associatedstructures, or both. TMD is the main cause of non-dental pain in the orofacial region and its prevalence has been increasing in recent years. The etiology of temporomandibular disorders (TMD) is considered complex and multifactorial; there is no single cause thattriggers TMD. The literature establishes as the main etiological factors of TMD: certain occlusal conditions, trauma, stress, deep pain, and parafunction. However, among the causes of TMD, one of the most controversial is the role that occlusion plays as an initiating, perpetuating and aggravating factor; its participation as an etiological factor becomes debatable. Due to the multifactorial and complex nature of temporomandibular disorders, we should not limit ourselves to rigid concepts.Until now, most studies have been based on static relationships to determine that there is no relationship between occlusion andTMD. However, the concept of occlusion encompasses: a static area and a dynamic one (mastication). A unilateral altered chewingpattern maintained for long enough could have effects on the development, perpetuation and aggravation of symptoms associated with TMD, such as pain. It is necessary to redefine the concept of occlusion (static and functional) in order to establish its relationship withtemporomandibular disorders; and how these can influence, taking into consideration the complex and multifactorial nature of TMD.