Parafunction × TMD: the influence of parafunctional habits in the etiology of temporomandibular disorders

It is clearly outlined in the literature the multifactorial nature of TMD. It seems to be consensus that structural, functional and psychological factors together determine its multifactorialorigin. The objective of this study was to emphasize the influence of parafunctional habits as etiological factors for the development of temporomandibular disorders, and to warn clinicians about the importance of careful evaluation of each case, avoiding under-diagnosing the parafunctions and uttering the correct treatment. It is not simple to establish a relationship of cause and effect between TMD and parafunctions because of the large number of factors that can influence them. It is vital to recognize that the etiology of temporomandibular disorders revolves around a triad of factors that are closely related. Psycho-behavioural, occlusal orneuromuscular changes are part of the context of the TMD’s etiology. Parafunctional habits influence the temporomandibular biomechanics, reaching levels sufficient to cause a collapse in the involved structures, but this can not be a proof of direct cause-effect relationship, due to a number of factors.