A sleep-related disorder that grinds teeth during nighttime sleep is called sleep bruxism and occurs in about 20% of children.Severe bruxism can cause significant wear on the deciduous teeth and pain in the jaw, but the mechanism is unknown.To elucidate, it is necessary to record the activity of the brain, heart, breathing, and jaw muscles during sleep with the cooperation of children who have no sleep and development problems, and specialized skills to analyze biological signal data are also required. Therefore, research is not progressing worldwide.

　This time, the research group set up a dedicated sleep examination room in the Graduate School of Dentistry of the same university, and as a result of conducting sleep examinations on children aged 6 to 15 years, 44 out of 15 children (27.3%) were bruxed. Admitted.Numericalization of overnight sleep depth and changes in autonomic nervous system activity showed that bruxism occurred most frequently in shallow non-REM sleep, which transitions to REM sleep later in each sleep cycle. rice field.

　In addition, the number of body movements (turning over) and the activity of electroencephalogram (β wave), which is an index of brain arousal, show higher values ​​in children with bruxism, and about 90% of bruxism is accompanied by short awakening and body movement. It was occurring.From the above, it was clarified that bruxism in healthy children may occur due to an excessive reaction of the neural mechanism of the jaw that grinds teeth to changes in brain activity associated with the sleep cycle.

　This time, it was found that the occurrence of bruxism in children is accompanied by changes in brain function associated with the sleep cycle.This is expected to lead to new research on diagnostic and therapeutic methods.

Paper information:[Sleep] Relationships between cortical, cardiac, and arousal-motor activities in the genesis of rhythmic masticatory muscle activity across sleep cycles in primary sleep bruxism children