Mandibular advancement devices are by far the most common type of dental sleep device available for the treatment of snoring and Obstructive Sleep Apnea (OSA). They are also sometimes called oral appliances, or dental sleep devices. Mandibular Advancement Devices (MADs) open the airway by moving the mandible (the lower jaw) forward. The tongue is attached to the lower jaw behind the chin. As the jaw is moved forward, the collapsible part of your airway is held open by the forward movement of the tongue and other airway muscles.Mandibular Advancement Devices (MADs) also improve the strength and rigidity of the airway by increasing the muscle activity of the tongue and other muscles of the airway.