Bruxism or "unconscious movement" can be a physiologic activity that it starts in the early period of the human life but it becomes a pathological situation when it produces muscle pain and/or excessive tooth wear or fracture and damages the stomatognatic system as severe malocclusion, degenerative joint conditions, periodontal tissue injury, disk derangement, headache, etc. Bruxism is characterized by grinding or clenching of the teeth. For approximately 50 years, bruxism has been advanced as a predominant factor in the onset or continuance of myofascial or muscle-pain-predominant temporomandibular disorders (tmds). [7, 8] Bruxism is the medical term used to describe the clenching and grinding of teeth. It may affect both children and adults and can be associated with a number of signs and symptoms. It is now understood that clenching and grinding are two separate en1. Definition and recognition of sleep bruxism