Bruxism is when a child clenches or grinds their teeth, which commonly happens at night.

Many children who clench also grind their teeth. Grinding is when you slide your teeth over each other, generally in a sideways, back-and-forth movement. This action may wear down your teeth and be noisy enough at night to be able to be observed. Like clenching, grinding can lead to jaw pain and other problems. 

The question is why do some children grind their teeth? 

Bruxism can be caused generally by struggling to breathe through a compromised airway (sleep apnoea ie cessation of breathing for 10 seconds or longer or other sleep disturbances). 

In other words if you see your child grinding their teeth or see that their teeth are worn down, please contact a dentist who is aware of the relationship between sleep disorders and bruxism. 

Children who have sleep disorders like sleep apnoea may not develop their jaws properly leading to crowding of their teeth. Some may develop ADHD, some children bed wet, some have multiple ear infections because their jaws have not developed well.  A paediatric ENT would assess for sleep disorders and the dentist makes sure development of the jaws is going on normally.