Mandibular advancement devices are an excellent alternative to CPAP or surgery in the treatment of sleep apnea.
First we have to ask, “what is obstructive sleep apnea?” Obstructive sleep apnea occurs when there is obstruction to the upper airway during inspiration while sleeping. Patients present most commonly with snoring, choking during sleep, and daytime sleepiness, sometimes unexplained leg swelling or edema. How does this happen? During the episodes when breathing is partially or completely obstructed, the patient will attempt to open the airway, appearing to an onlooker as loud snoring or choking. This causes a tremendous outpouring of adrenaline, for obvious reasons, and long-term exposure to all of this adrenaline brings about elevated blood pressure and sometimes cardiac arrhythmias. Simultaneously the oxygen level drops. Prolonged exposure to low oxygen for so many hours brings about pulmonary hypertension and fluid retention. The patient will unconsciously attempt to open airway. In order to open the airway, the patient has to awaken briefly, perhaps 5-15 seconds at a time. These repetitive mini-awakenings break the continuity of sleep, causing sleep deprivation. The patient would feel very tired the next day, experience some memory impairment, and could easily fall asleep while driving.
There are three sites of complete or partial obstruction of the upper airway - nasal, retropalatal, and retrolingual (see picture). Nasal obstruction, which everyone has experienced causes reduced airflow through the nose and forces the person to become a mouth breather. When the person is forced to become a mouth breather, the jaw relaxes and moves posteriorly or backward so that the tongue collapses against the pharyngeal wall or the back of the throat. This is called retrolingual obstruction. Sometimes people can block this area even if their noses are clear. Between the nose and back of the tongue is the retropalatal area. If one looks at the back of throat, one sees the uvula and the arch of the soft palate. Obstruction can occur at this level, too, if the area is narrow or swollen.
How do we relieve the obstruction?
The simplest thing to do with just about everybody is keep the nose clear of secretions and prevent excess mucus or congestion. This can be accomplished with antiallergy measures in the house as well as nasal steroids, antihistamines, and decongestants. Often, unfortunately, this is not enough.
The standard of care that is used as first line therapy for sleep apnea is nasal CPAP. CPAP stands for Continuous Positive Airway Pressure. There is a variation called BiPAP, which stands for Bilevel Positive Airway Pressures, in which there are two pressure settings, but the general concept is still the same. A tight fitting mask is placed over the nose or the nose and mouth or a mouthpiece alone is used. It is connected through a host to a machine and there is flow of air that generates pressure. As one breathes in, this positive airway pressure pushes everything out of the way and keeps the airway open. Once the airway opened, the problems that we outlined earlier are all solved. Although CPAP is extremely effective, this is not the most comfortable therapy and many patients find it difficult to use, somewhat cumbersome.
Mandibular advancement appliances are dental mouthpieces worn at night that position the jaw forward, or anteriorly, pulling the jaw and tongue in such a position that the tongue does not fall back against the posterior wall. The airway opening is therefore maintained. Side effects include tension on the TMJ joint and some soreness of jaw muscles. Sometimes there is a slight increase in saliva, but that usually resolves in a day or two. There are variety of mandibular advancement devices on the market, such as the Klearway, Herbst appliance, Oasys, TAP, Somnomed, and Silent Nite, being some of the better-known brands. For a dental appliance to work effectively, it must be adjustable and comfortable. All require proper fitting by a dentist who is familiar with such devices. In order determine if a patient is a candidate for such a device, the patient should be seen and evaluated by a sleep physician, and undergo a sleep study. The Central Jersey Sleep Disorders follows a special protocol with a temporary appliance to determine beforehand if the patient will tolerate a mandibular advancement device, as well as establish the optimal position for the device.
