A mouthpiece for oral delivery for oral delivery of CPAP treatment has a vestibular shield for location between the teeth and lips/cheeks of a wearer. The vestibular shield is dimensioned to extend laterally into the buccal vestibule and vertically to overlap the gums. The vestibular shield is formed from a very supple material. A gases pathway is provided through the vestibular shield and may include a hard plastic insert through the shield, including a standard breathing conduit connection at its outer end. A short stub conduit on the outlet side of the shield passes between the wearers upper and lower teeth. A connection for connecting the mouthpiece to a breathing circuit is also provided which reduces the transfer of forces caused by movement therebetween. The connection may include a short length of highly flexible gases conduit, an elbow and a swivel connection. <;IMAGE>;