The course will focus on Obstructive Apnea Syndrome (OSAS). The concepts relating to the physiology of sleep will be introduced first. The most common signs and symptoms of sleep breathing disorders will be illustrated, such as snoring and bruxism and the sentinel role of the dentist and dental hygienist. The indications and methods of use of mandibular advancement devices (MAD) and finally the periodontal implications of OSAS will be explained.