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.
