Relationship between oral parafunctions and craniomandibular dysfunction in children and adolescents: a review

A review of the literature on the relationship between oral parafunctions and craniomandibular dysfunction is presented. The interpretation of the results was performed by applying the epidemiologic approach of "necessary and sufficient" which implies that there must be a one-to-one relationship between the factor and the disease. In all studies but one bruxism was constantly correlated with signs and/or symptoms of craniomandibular dysfunction indicating that a one-to-one relationship exists between this parafunction and the dysfunction of the masticatory system. Also, the reported correlations were highly significant. The strength and consistency of correlations support causality. The causal relationship between the rest of the oral parafunctions and craniomandibular dysfunction needs further investigation. On the basis of the evidence provided by the reviewed studies, bruxism cannot be considered as necessary, but a sufficient cause of craniomandibular dysfunction for a certain group of individuals.