Bruxism originates from a complex interaction between the central nervous system, jaw muscles, and tooth alignment. During sleep, the brain cycles through stages of arousal where the masseter muscle, one of the strongest muscles in the body, can generate forces exceeding 250 pounds per square inch, far beyond normal chewing pressure of approximately 20 to 40 pounds.
These involuntary muscle contractions are often triggered by micro-arousals during sleep, brief shifts from deeper to lighter sleep stages that activate the trigeminal nerve pathway. Research shows that stressed adults are approximately two times more likely to develop bruxism, as elevated cortisol levels directly influence nighttime jaw muscle activity.
An improperly aligned bite, or malocclusion, creates uneven contact points between the upper and lower teeth. When these surfaces do not meet evenly, the jaw muscles compensate by clenching or shifting, which can initiate or worsen grinding patterns over time.
