A mouthpiece includes a buccal retention feature that produces frictional attachment to the lateral buccal portions (inner cheeks) of the individual user. The mouthpiece includes a U-shaped body sized and shaped to conform to the outer face of the dental arch. The retention feature includes bulbous protrusions that project laterally outward from the body to engage the cheek. The mouthpiece, and particularly the buccal retention feature, has a width that is large enough to prevent dislodgment or removal of the device from the mouth, taking advantage of the decrease in the intercommissural distance as the mouth is opened to attempt to remove the device. The device further includes a duct portion extending forward, outside the mouth, from the body, to permit normal respiration through the duct portion. The duct portion can be configured to connect to other devices, including but not limited to, devices for rebreathing, suctioning, feeding or delivering medicaments.
