Bruxism is forcible grinding or gnashing of the teeth. This is common in children, and as a parasomnia, said to occur in 5-20% of the population during nonREM sleep. Masseter hypertrophy may become apparent in persistent grinders. Bruxism may also occur in encephalopathic disorders (e.g., hepatic encephalopathy) and occasionally in disorders of the basal ganglia (multiple system atrophy, basal ganglia infarcts). Dysfunction of efferent and/or afferent thalamic and striatopallidal tracts has been suggested as the neural substrate.
If necessary, a rubber device or bite may be worn in the mouth to protect the teeth. Botulinum toxin injections have also been tried.
Glaros AG, Rao SM. Bruxism: a critical review. Psychological Bulletin
1977; 84: 767-781