Bruxism is a paroxysmal disorder that is characterized by the clenching or grinding of teeth. The effects of bruxism or night grinding include tooth destruction and joint pain. Constant grinding and clenching produces wear facets on the teeth and when much of the structure is lost, vital tissues may be exposed thus causing teeth sensitivity. When the problem is allowed to progress, much of the teeth surface is lost so that the bite collapses, and the temporomandibular joint is left to endure the damage. Whether or not the condition progresses this way, a patient with prolonged night grinding habits will experience symptoms that may easily be mistaken for a TMJ disorder. Jaw pain, aching muscles inability to move the mouth effectively and so forth. Night guards treat bruxism by acting as a protective barrier between the upper and lower teeth.