Abstract: The present invention provides intra-oral interfaces, systems and methods for preventing sleep apnea, the interfaces comprises a conduit adapted to receive continuous positive airway pressure (CPAP) from a CPAP source, and for delivering positive air pressure to a mouth of a patient, a mouthpiece through which the conduit extends, the mouthpiece having a portion configured to reside between the teeth and inner part of the lips and cheeks in the mouth of the patient; and an active seal associated with the mouthpiece, the active seal having at least a portion thereof adapted to reside in a buccal vestibulum of the patient, the active seal being configured to bulge and contract as the patient breathes.