Objective: To examine the phenomenon of bruxism and assess the current state of the literature regarding its role in temporomandibular disorder (TMD). Data sources: A review of the literature contained in the CINAHL; Pubmed; COCHRANE; MANTIS and MEDLINE (ovid) database searches as well as hand searches was conducted between September 2005 and March 2006. Study selection: Studies using the keywords bruxism, temporomandibular, jaw, randomised controlled trial, survey, epidemiological, longitudinal, were screened. Uncontrolled studies, case studies, case series and reviews were ignored. A total of 172 studies were identified and compared in terms of their definition of bruxism, TMD, and conclusions regarding the role of bruxism. Conclusion: The majority of studies found a relationship between bruxism and TMD. However, inconsistency and equivocation of different parafunctional activities are common within the literature. The subject is further complicated by the lack of a universally accepted definition of both TMD and bruxism and an additional failure to standardise investigative variables such as frequency, duration and intensity of episodes. The role of bruxism as it is currently described can therefore be considered a controversial and unresolved issue. The authors suggest that the term bruxism be abandoned in favour of a set of diagnostically more appropriate descriptors.