An intraoral mandibular advancement device for treatment of sleep disorders includes a maxillary appliance having a protrusive element distending from the anterior portion of the maxillary appliance, and a mandibular appliance having a polymeric shell with recesses to receive and removably engage the mandibular teeth. A lingual spacer extends posteriorly from the anterior portion of the mandibular appliance to contact the anterior aspect of the protrusive element and thereby cause mandibular advancement. An anterior stop extends upward from the occlusal surface of the anterior portion of the mandibular appliance to contact the anterior portion of the maxillary appliance and thereby maintain separation between the anterior teeth and provide a mechanism, by way of its vertical reduction, to reinstate posterior contacts as the jaw moves forward. Posterior stops on the occlusal surface of the posterior portions of either appliance maintain separation between the posterior teeth.