A method, system, apparatus, and/or device for adjusting a mandible of a user. The method, system, apparatus, and/or device may include: a top tray configured to be inserted into a mouth of a user to form around upper teeth of the user； a top position adjuster attached to a bottom portion of the top tray: a bottom tray configured to be inserted into the mouth of the user to form around lower teeth of the user； and a bottom position adjuster attached to a top portion of the bottom tray, where the top position adjuster and the bottom position adjuster are adjustable to move the top position adjuster or the bottom position adjuster laterally or longitudinally.
