Dentistry has been involved with treating sleep disorders for over twenty years. Tongue retaining devices and mandibular advancement appliances have been used to correct snoring and sleep apnea since the 1980s. High level clinical studies have confirmed that oral appliances are effective in treating sleep apnea.
The most common sleep disorders treated by sleep dentistry are snoring, obstructive sleep apnea, and upper respiratory resistance syndrome (URRS).
Snoring is the primary reason why people seek medical help because it disturbs the patient’s sleeping partners. Snoring is caused by a vibration of the soft palate and other soft tissues of the throat. By itself it is not as much of a health threat but it is the first stage of the other sleep disorders.
Apnea is the Greek word for “without breaths” Sleep Apnea has grave medical implications if it is not corrected. There are several types of sleep apnea.
Obstructive sleep apnea (OSA) is caused by a lack of muscle tonicity of the tongue and throat muscles during sleep. The throat muscles are completely paralyzed during REM sleep and stage IV deep sleep. REM stands for Rapid Eye Movement sleep. During inspiration (breathing in) the tongue collapses into the back of the throat and the patient stops breathing. As oxygen levels in the blood drop, the heart beats faster. When the body recognizes this crisis it releases adrenaline into the blood stream constricting the blood vessels and creating an arousal. This often happens hundreds of times during the night.
Central sleep apnea is a less common neurological problem where the brain does not give a signal for the person to breath. The consequences are the same as OSA but there is no obstruction. Oral appliance therapy and CPAP are not as effective in treating this condition. Central Sleep Apnea patients often have a combination of central and obstructive sleep apnea.
Upper Respiratory Resistance Syndrome is another condition, more commonly found in women. URRS is a condition where the patient has light obstruction of the airway but has a low level of the apneas or hypopneas. The light obstructions however do cause arousals (awakenings) during the night and cause the patient to suffer from fatigue and headaches.
The severity of sleep apnea is determined by an overnight sleep study. Severity of sleep apnea is measured by the Apnea Hypopnea Index, AHI. The AHI is the average number of apneas plus hypopneas that a patient experiences per hour of sleep. An apnea is defined as complete stoppage of breathing for more than ten seconds. A hypopnea is defined as a 50% restriction of airflow causing a 4 % drop of oxygen in the blood followed by the patient being stimulated into a lighter level of sleep (arousal).
The results of a sleep study will show the type of sleep apnea, and measure its severity. Normal is AHI 0-5, mild 5-15, moderate 15-30, and severe 30+. The degree and frequency of oxygen desaturations may also be an important parameter, particularly in patients with cardiovascular compromise. In general, most clinicians use a subjective mild, moderate, or severe classification if referring to oxygen desaturations. Desaturation levels below 89% are considered abnormal.
The consequences of Sleep Apnea are significant. Apnea suffers often do not get a restful night sleep, causing headaches and drowsiness during the day. This can also put someone at an increased risk of vehicular or industrial accidents. The oxygen deprivation apnea sufferers experience every night is also associated with high blood pressure, heart attacks and strokes. It has also been linked to depression, heartburn and reduced sex drive.
Sleep Apnea is associated with 80 % of the uncontrolled hypertension treated by medications, 50 % of heart diseases, 50 % of type II diabetes, 40 % of strokes and a majority of the patients suffering from gastric reflux. Day time fatigue is the primary complaint because of the fragmented sleep patterns. Nearly 35 % of all traffic accidents are now associated with drowsiness and sleep disorders.
Fatigue in sleep apnea patients is caused by the fragmentation of the REM sleep and Stage III and IV sleep levels. REM sleep should occur 25 % of the night in three to four episodes of 15 to 45 minutes each. REM sleep is essential because growth hormones and other chemicals responsible for memory and brain rejuvenation are released only during this stage. Stage III and IV deep sleep should occur 20 % of the night and are also important for the patient to feel refreshed. Each apnea or hypopnea brings the patient out of deep sleep into stage I or II sleep. Thus, sleep apnea patients may sleep 8 to 9 hours per night but can suffer from extreme drowsiness, fatigue or memory loss.
Children can also snore and suffer from obstructive sleep apnea. Often they are highly allergic and their airway is blocked due to enlarged adenoids, tonsils or swollen nasal mucosa. Clinical signs would indicate a turned up nose, allergic shiners under the eyes, mucous draining out of the nose, mouth breathing, and a nasal sound to the voice. Other signs are bed-wetting, irritability, difficulty in concentrating at school and hyperactivity.
Children can also snore and suffer from obstructive sleep apnea. Often they are highly allergic and their airway is blocked due to enlarged adenoids, tonsils or swollen nasal mucosa. Clinical signs would indicate a turned up nose, allergic shiners under the eyes, mucous draining out of the nose, mouth breathing, and a nasal sound to the voice. Other signs are bed-wetting, irritability, difficulty in concentrating at school and hyperactivity.
Sleep disorders must be diagnosed by a physician. Dentists may evaluate patients for sleep disorders but are not allowed to diagnose sleep apnea or other disorders. Diagnosis is made from a combination of examinations and tests. Anyone with a combination of snoring and co-morbid conditions such as hypertension, diabetes, heart disease or stroke absolutely should undergo comprehensive sleep evaluations. Snoring with fatigue, headaches, impotency or heartburn would also warrant a sleep study.
The gold standard for the diagnosis of sleep apnea is the attended Polysomnography (PSG). An attended PSG is a night study performed at a sleep center. The patients sleep is monitored with up to 16 different channels, including heart rate, blood oxygen levels, brain wave activity, nasal airflow, snoring, and muscle activities. The test is then scored by a trained sleep physician who makes the final diagnosis and recommends treatment.
Ambulatory (take home) studies are also used by physicians. Even though they may not be as accurate, new regulations will allow these studies under certain situations for diagnosis. Our office will use simplified ambulatory devices for monitoring treatment progress but cannot use these for diagnostic purposes.
The treatments for sleep apnea include Oral Appliance Therapy (OAT), Continuous Positive Airway Pressure (CPAP), various surgeries and oral neuromuscular rehabilitation (ONMR). Treatment goals vary with each patient. The standards established for surgery and CPAP in mild and moderate cases are to reduce the AHI to below 10 with reduced symptoms. The standard for successful treatment for severe sleep apnea is to reduce the AHI by more than 50 %. We feel that this goal is too liberal in most cases. Conditions affecting our goals include smoking, alcohol consumption and morbid obesity.
Oxygen saturation index is also used to establish treatment goals. Normal/average oxygen saturation is greater that 92 %. Saturations below 89 % are considered abnormal. Heart disease and pulmonary problems can have a great effect on this index. Oxygen supplementation is sometimes used as an adjunct to CPAP and OAT.
CPAP therapy has been the gold standard for treating sleep apnea. CPAP works by creating air pressure through the nose or mouth with an air compressor, hoses and masks. The air pressure forces the tongue forward and widens the throat. The more severe sleep apneas require higher air pressures. Most sleep apneas can be corrected with CPAP but not all patients are comfortable with this form of treatment. Studies show that less than 50 % of the patients prescribed to use CPAP are still using them after just one year. Side effects include, bloating, skin irritation, dry eyes, inability to move during sleep, and inability to sleep due to noise from hoses. Because of the low compliance rate the American Association of Sleep Medicine (AASM) has recently made OAT an alternative first line of treatment.
OAT was adopted by the AASM in 2006. There are currently over 70 different oral appliances on the market (see oral appliances). Most oral appliances work by holding the lower jaw down and forward. This pulls the tongue away from the back of the throat and tightens the tongue and pharyngeal muscles. Some of the newer appliances also dilate the nasal passages or physically reposition the tongue.
Clinical studies of the new appliances show compliance rates greater than 90 %. Oral appliances also protect the patients teeth form clenching, help correct TMJ temporalmandibular joint) problems, and prevent headaches. Side effects may include bite changes, tooth sensitivity, and dry mouth. The AASM recommended that OAT should only be administered by dentists trained in sleep medicine and TMJ therapy.
A large percentage of sleep apnea cases were originally treated with surgeries. The surgeries included cutting away the soft palate, tonsils and adenoids, enlarging the back of the throat and reconstructing the upper and lower jaw bones. Removing the tonsils and adenoids has been very beneficial for children. Jaw reconstruction is effective in some cases but is very expensive and painful. Cutting away the soft palate and the back of the throat often stops snoring but is not recommended by the American Academy of Sleep Medicine (AASM) for treating obstructive sleep apnea. Many sleep patients suffer from nasal obstruction and find both CPAP and OAT are nhanced when a patient can comfortably breathe through their nose. Our office routinely measures for nasal obstruction and will refer to ENT’s for treatment.
Oral Neuromuscular Rehabilitation (ONMR) is another method that our offices have used to treat sleep apnea. The treatment involves a series of muscle training exercises that increases the resting tonicity of the muscles of the tongue and throat. The therapy was developed by Alan and Sonna McKee, our oral myologists. Limited clinical studies have had great success in permanent sleep apnea correction. We are in the process of making ONMR available to everyone after further studies.
50 % of sleep apnea patients have TMD. TMD is a term used to describe problems of the temporalmandibular joint (TMJ), the mandible, neck, and muscles of .mastication. Symptoms of TMD are headaches, neck aches, TM joint pain, restricted opening of the jaw, TMJ noises, ringing of the ears, stuffy ears, hearing loss, speech difficulties, and swallowing disorders.
The American Association of Sleep Medicine (AASM) and the American Academy of Dental Sleep Medicine (AADSM) require a thorough analysis of the patient for TMD. Oral appliances can be designed to improve the health of the TMJ if diagnosed before treatment. For more difficult cases, a smaller day time appliance may be prescribed to stop headaches or recapture a dislocated cartilage. In some cases TMD problems and headaches are caused by bite misalignments. After correcting the TMD problems, we will refer the patient back to their dentist for the necessary follow up treatments.
TMD is diagnosed by a comprehensive exam, medical/dental history review, x-rays, and computerized functional studies (see technology. -JVA, EMG). We have been successfully treating TMD for over thirty years.
The severity of sleep disorders can change quickly and easily. The factors causing these changes include allergies, eating habits, weight gain, air quality, age, and general health of the patient. For these reasons all treatment types including OAT should be monitored periodically. A follow up exam, appliance check, Epworth sleepiness study (ESS) and ambulatory home study should be completed every 6 months the first year and yearly after that.
