Noctumal oral airway dilator

An oral appliance includes first and second mouthpiece elements each equipped with adjustable ribs on an anterior portion and ramp surfaces on each of its posterior arms. The ribs slope upwardly, front to back at a steeper angle than the ramp surfaces. Preferably, the ribs and the ramps surfaces have maximum height which define a ratio in the range of between 2 and 2½ to mimic the differential in mouth opening between incisors and molars. The appliance has a plurality of laterally extending protrusions that are engaged by elastic bands to exert a force which simultaneously pulls the wear's mandible forward and biases the lower mouthpiece toward the upper mouthpiece. Adjustable ribs extend laterally to permit relative movement of the two mouthpiece elements to eliminate the buildup of tension in the wearer's jaw.