December 15, 2007
Obstructive sleep apnea syndrome (OSAS) is a common condition seen in middle-aged persons. As many as 40-50% of adults aged 60 years or older have some form of sleep related breathing disorder, most commonly snoring. The condition is characterized by partial or complete upper airway obstruction during sleep, causing conditions referred to as apnea and hypopnea. Day time symptoms are also common, most often excessive sleepiness. Apnea is the cessation of airflow at the nose or the mouth for at least 10 seconds. Hypopnea is a 30% to 50% reduction in airflow for at least 10 seconds and a partial loss of oxygen saturation in the blood of at least 2% to 4%. A diagnosis of OSAS requires at least five instances of apnea or hypopnea, or both, per hour of sleep and it usually ends with arousal from sleep. The total number of apneic and hypopneic episodes per hour of sleep is called either the apnea-hypopnea index or the respiratory disturbance index. The apnea-hypopnea index (AHI) is defined as the number of apneas and hypopneas per hour of sleep. The respiratory disturbance index (RDI) is used by sleep laboratories to report the number of apneas and hypopneas per hour of sleep. Patients with moderate to severe OSAS have significantly increased mortality, and considerable data reveals that even mild to moderate OSA (RDI 5-15/hour) increases the risk for hypertension, stroke, myocardial infarction and injury due to motor vehicle accident.
The most common symptoms of OSAS are snoring, excessive daytime sleepiness, nocturnal (night-time) snorting and gasping, and witnessed apneic episodes. Snoring usually precedes the complaint of excessive daytime sleepiness. Cessation of breathing reported by the bed partner is usually a source of great anxiety because of fear that breathing may not resume. Other nocturnal symptoms include restlessness, diaphoresis (excessive perspiration), awakenings with a sensation of choking or dyspnea, esophageal reflux with subsequent heartburn and laryngospasm, frequent nocturia (urinating at night), dry mouth, and drooling. Tiredness and sleepiness are the most common complaints; upon awakening, patients do not feel refreshed and often find it difficult to get out of bed. Some feel mentally dull, groggy, confused, or disoriented. Daytime sleepiness occurs during boring, sedentary situations in the afternoon or evening. Patients may describe difficulty remaining awake during meetings after lunch or while driving or reading. As sleepiness becomes more severe, patients may fall asleep during conversation, while on the telephone, or during sexual intercourse. The most catastrophic result of excessive daytime sleepiness is falling asleep behind the wheel and causing injury or death.
Management of OSA includes diet modification and weight loss, positional sleep therapy, continuous positive airway pressure (CPAP), nocturnal oral [repositioning] sleep apnea device and a variety of surgical procedures. No medications are presently available for primary treatment, although tri-cyclic antidepressant medications (especially protryptiline) and GABA antagonists can reduce OSA complications. Oral sleep apnea devices have been shown to reduce the severity of respiratory disturbances during sleep and are most effective for subjects with an RDI of less than 40 episodes per hour. Oral devices have been developed for mechanically enlarging or stabilizing the upper airway by advancing the mandible (lower jaw bone) or tongue. Compared to uvulopalatopharyngoplasty (UPPP) or other more complex facial reconstruction surgical procedures, oral sleep apnea device therapy cost less and has the advantage of being easily terminated without any severe side effects. Compared to protriptyline, oral sleep apnea device therapy has more efficacy and the side effects are better tolerated.
Oral sleep apnea devices, particularly mandibular (lower jaw) repositioning sleep apnea devices, are fitted to the upper and lower teeth and are connected to allow both vertical opening and anterior repositioning as necessary to effectively dilate the airway and improve breathing. Edentulous individuals (people without teeth) and denture wearing subjects have not been candidates for mandibular repositioning sleep apnea devices due to the lack of adequate retention of the denture bases in holding the jaw in an advanced position. Dental implants have a high degree of success in the replacement of missing teeth and implant-retained dentures are becoming the standard of care for stabilizing removable prostheses as they minimize loss of bone in the lower jaw, improve oral function, esthetics, chewing ability, and dietary intake of essential minerals and vitamins from food sources otherwise avoided in these subjects due to their difficulty in chewing nutrient rich fibrous fruits and vegetables.
The New York University Bluestone Center for Clinical Research has begun a novel research investigation to determine if removable oral sleep apnea devices can be constructed with implants for the treatment of sleep apnea in adult patients without any remaining teeth. This multidisciplinary study involves experts in sleep apnea, respiratory medicine, dental prosthodontics, and oral medicine from the NYU College of Dentistry and the NYU School of Medicine.
For more information, please call the Bluestone Center for Clinical Research at 212-998-9310.