Teeth grinding during sleep is common and often goes unnoticed by the sleeper.

The longer version

Rhythmic jaw muscle activity during sleep produces clenching or grinding, sometimes loud enough to disturb a bed partner while the sleeper remains unaware. The forces involved can be several times those of ordinary chewing. The episodes are brief and often cluster in lighter stages or brief arousals.

Laboratory recording finds the behaviour in a substantial share of adults, with wide variation between nights, so a single session can easily miss it. Stress, alcohol and certain medications raise its frequency. Jaw pain and morning headaches are among the signs that prompt an assessment. Dentists often notice the effects, such as worn enamel, before the sleeper does.

Where this entry sits

This collection gathers curious details about sleeping and dreaming, from nightly brain stages and body clocks to naps, yawns and unusual animal habits. It also covers how bedtime customs have changed across centuries, without offering any advice. The full list sits on the Sleep and Dreams page, where every entry is listed in order.