Various definitions, classifications and theories been ascribed to bruxism. Knowledge gained through expanding research initiatives have transformed some of the concepts that were once held as truths. Sleep bruxism is no longer considered a parasomnia nor is its etiology believed to be based on purely mechanical factors or psychological Issues. It is now considered to be primarily a sleep-related movement disorder with a yet to be determined multifactorial etiology involving complex multisystem physiological processes. Dental practitioners should recognize the transformation occurring in the study of sleep bruxism, understand the evolution in both definitions and classification of this phenomenon and embrace and consider new concepts related to its etiology. This paradigm shift will certainly affect the daily practice of dentistry.