In which sleep stage is bruxism most commonly observed?

Bruxism, which refers to the grinding or clenching of teeth, is most commonly associated with the N2 stage of sleep. During this stage, individuals experience lighter sleep and a more regular sleep cycle, where muscle tone can fluctuate, potentially leading to the involuntary grinding of teeth. While bruxism can occur in different sleep stages, many studies have indicated that it is particularly prevalent during N2 due to the heightened arousal response coupled with sleep stability.

N1 is characterized as the transitional stage between wakefulness and sleep and is generally too light for bruxism to take place significantly. N3 represents deep sleep, where muscle activity is significantly reduced, making teeth grinding unlikely. REM sleep features intense brain activity, vivid dreams, and temporary paralysis of most skeletal muscles, which would inhibit the ability to grind teeth effectively. Thus, the evidence supports that bruxism occurs most frequently during the N2 stage.