Sleep disordered-breathing is a common problem. Hypopnea Syndrome/Obstructive sleep apnea is a serious health issue that can be treated using surgery, Continuous positive airway pressure(CPAP) and oral appliances therapy. Oral appliance therapy is a viable, non-invasive treatment for patients with mild to moderate Obstructive sleep apnea. Keys to success in treating patients with an oral appliance include patient selection following a thorough clinical examination and a definitive diagnosis of OSA, selection of the appropriate appliance, and case management during treatment.