Abstract: An apparatus for preventing sleep apnea in a wearer comprises upper and u-shaped appliances, a bottom protrusion extending from the lower appliance in a direction generally away from an occlusal surface of the lower appliance and a top protrusion extending from the upper appliance, the top protrusion including an adjusting block having a height of between 5/16 and 13/32 of an inch adjustably extending therefrom and having a leading surface oriented to engage the top protrusion. A method for preventing sleep apnea in a wearer comprises locating the top protrusion below and extending away from the top occlusal surface of a wearer's upper teeth, locating the bottom protrusion above and extending away from the bottom occlusal surface of a wearer's lower teeth and extending the adjusting block in an anterior direction from the top protrusion towards the bottom protrusion.