Abstract: Systems, devices, and methods for retaining a treatment device in the patient's oral cavity through the course of treatment are provided. Retainer elements, which match the upper and lower teeth of the patient, are worn by the patient and coupled to the bite plate of the treatment device. The upper and lower retainer elements can be coupled to the bite plate or otherwise positioned relative to one another such that the lower teeth and mandible are advanced in the anterior direction, which helps maintain airway patency. The treatment device can also apply a vacuum to the oral cavity to help maintain airway patency.