Sleep apnea is a common but serious sleep disorder that occurs when regular breathing is interrupted during sleep. Obstructive sleep apnea is the more common form; it is the result of blocked airflow when the soft tissue at the back of the throat collapses during sleep. Certain oral devices can shift and support the jaw to prevent the airway from collapsing. Research shows that oral appliances can successfully prevent sleep apnea in some mild to moderate cases.
https://www.mouthhealthy.org/en/az-topics/s/sleep-apnea-and-snoring