MULTILEVEL ORAL APPLIANCE TREATMENT
SUMMARY
Many dentists now treat obstructive sleep apnea (OSA) with oral appliances that advance the mandible (the lower jawbone). These mandibular advancement appliances are well tolerated by patients; but they have limited effectiveness, because the stopper that obstructs the airway is the tongue base, and it is only attached to the mandible by muscles, which naturally lose tonus during sleep. Dr. Summer has devised mechanisms that can be added to ineffective mandibular advancement appliances in order to also control the postures of the tongue and soft palate - the soft tissues that produce the actual obstruction. Such a comprehensive approach should make oral appliances effective enough to become a first line treatment for OSA. A detailed description of the new soft tissue controls as well as an improved mandibular advancement technology can be found in the file entitled, MULTILEVEL ORAL APPLIANCE TREATMENT under the FOR DOCTORS tab.
BACKGROUND
Obstructive sleep apnea (OSA) is caused by choking on the tongue during sleep. It affects millions of people, but current treatment for it is problematic. Minor surgeries can be helpful but rarely curative. CPAP is usually effective if the pressure is high enough, but compliance is poor, because many people find it difficult to tolerate. Oral appliances currently used to treat the problem work by advancing the mandible, which increases the space available in front of the tongue, but cannot draw the tongue forward into that space. As a result, even extreme mandibular advancement cannot prevent the tongue from falling back into the throat to block the airway, it just has further to fall. In some people, the stopper is formed by loose soft tissues like the soft palate filling in the narrow gap between the trongue and the back of the throat like a gasket.
We have new mechanical devices that can be added to ineffective mandibular advancement appliances to make them more effective by also controlling the tongue and the soft palate. The tongue is advanced with the mandible to prevent it from dropping back into the throat, the middle of the soft palate is elevated to pull its end away from the obstruction, and the tongue base is pried off the back wall of the throat. To prevent unnecessary treatment, these modalities, illustrated below, can be added one at a time until the problem is solved.
The suggested clinical protocol for patients with a full set of teeth is described below. Edentulous patients (no teeth) cannot undergo mandibular advancement, but they do especially well with tongue holding and soft palate elevation, so their treatment is described in a separate file.
STAGE ONE – The first stage of multilevel oral appliance treatment for patients with natural teeth involves using an adjustable mandibular advancement appliance to gradually move your mandible further forward until you find the most advanced position that you can comfortably tolerate. A variety of oral appliances are currently available for this "titration" process from your local dentist. They all cause bite changes, which should be treated by bite adjustment, usually by your dentist, as explained further at the end of the file entitled MULTI-LEVEL ORAL APPLIANCE TREATMENT OF SLEEP APNEA under the FOR DOCTORS tab.
Telescopic (Herbst) appliances have the longest history of success in treatment for sleep apnea and the best control over mandibular position, but the hardware they employ was designed more than a century ago for bite jumping in children, and it is unnecessarily bulky and restrictive when used in adults, leading to discomfort and breakage. To solve these problems, Dr. Summer's high push Herbst appliance is almost unbreakable, has a lower profile for comfort, allows free lateral movement to ensure TMJ health and prevent binding, pushes the mandible upward and forward rather than downward and forward in order to facilitate keeping the mouth closed, and has unlimited adjustability without tools by just rotating the tubing assembly on the threaded connector, as shown below.
BEFORE ADVANCING AFTER ADVANCING
Mandibular advancement is often combined with a soft palate elevator to open the nasopharyngeal airway, where the distal end of the soft palate and adjacent loose soft tissues get sucked into the space between the tongue base and the pharyngeal wall. Here the distal end of the soft palate fills the narrrow gap between those tissues to complete the airtight seal like a gasket, as shown below.
The soft palate elevator employs a silicone rubber bulb on the end of a thin flexible arm to “tent” the middle of the soft palate, where there are few gag reflexes, in order to draw its distal end, which is full of gag reflexes, upward and forward away from the obstruction, as shown above. The soft palate is a thin flap of tissue that has almost no tonus during sleep, and a light force is able to keep it elevated about 1/4” all night without causing any discomfort.
At the end of stage one treatment, some type of follow-up sleep testing is necessary to find out how well the treatment is working. If it's only partly effective, you'll feel better, but you'll likely relapse over time as the remaining incidents continue stretching out the soft tissues of the pharynx. Our fee for stage one treatment is $3500.
STAGE TWO – The next stage of multi-level oral appliance treatment is to grasp the tongue between specialized upper and lower tongue gripping surfaces that each contain thousands of forward slanted bristles, (AKA tongue velcro), to prevent it from dropping back into the pharynx. The tongue gripping surfaces are so effective that they require very little compressive force to hold the tongue all night in the space shown below.
A lower tongue gripping surface is shown below left and an upper tongue gripping surface is shown below right.
To prevent accidental release of the tongue during sleep, at least one of the upper tongue gripping surfaces (the upper for patients with teeth and the lower for denture patients) is mounted in a continual biasing mechanism that creates a cushioned grip which persists throughout the submaximal mandible and tongue movements that occur during normal sleep. The cushioned grip continues until the mouth is opened wide enough to release the tongue. In most people, the target position for the tongue is just far enough forward for its tip to maintain light contact with the lips closed around it, as shown below. Patients go to sleep with the tongue in this target position, and they awake with the tongue in the same target position, because the tongue cannot escape during sleep.
STAGE 3 - If follow-up sleep testing shows that the apnea persists, the remaining airway blockage probably occurs down lower in the hypopharynx. To treat the hypopharyngeal obstruction, the tongue base is gradually pried off the pharyngeal wall by adjustment mechanisms called tongue base titraters that are mounted on the back of the upper tongue gripping surface, which is braced by the gripped tongue and the mandible resting on the bite stops, in progressive weekly increments, as the patient gets accustomed to them.
The three rows of apertures in the tongue base titraters enable the direction of depression to be varied by 25 degrees, as shown below.
UNADJUSTED DOWN AND BACK DOWN AND FORWARD
The hypopharyngeal obstruction is treated by first shifting the tongue base titraters down and back to get behind the tongue base, as shown below on the farther tail segment; and then rotating them forward in two steps through that 25 degrees in order to pry the tongue base forward off the lower pharyngeal wall, as shown below on the nearer tail segment.
FACTORS COMPLICATING TREATMENT
MOUTH BREATHERS - Mouth breathing is devastating to health, because the air that hits the back of the throat has not been warmed, filtered, and moistened by the nose. Some people are obligate mouth breathers, because their nasal cavity is too narrow to allow adequate airway flow. Other people have a nasal cavity that is just wide enough to allow normal nasal airway flow become obligate mouth breathers whenever allergies or rhinitis causes swelling of the nasal mucous membranes. Obligate mouth breathers can be converted to nose breathing after palatal expansion to widen the nasal airway. However, palate expansion it rarely eliminates apnea, because the area that is widened is located far from the back of the throat where the obstruction occurs.
Habitual mouth breathers use an oral airway despite having an adequate nasal airway passage, and their mouth breathing habit can usually be eliminated by almost any mechanism that can hold the mouth closed; including chin straps, lip taping, thick foam cervical collars, or interarch orthodontic elastics on an oral appliance that fits on the teeth tightly enough to resist being pulled off them by the weight of the lower jawbone.
TMJ DISORDERS - can make it difficult to advance the mandible rapidly or extensively, but they usually resolve by middle age when OSA begins, so they rarely prevent gradual mandibular advancement, and they certainly do not prevent soft palate elevation or tongue holding.
BITE CHANGES - are frequent consequences of nightly mandibular advancement due to a combination of tooth movement and jawbone growth. Patients usually find that their back teeth no longer fit well together in the morning and then throughout the day, because the upper front teeth have shifted slightly backward, the lower front teeth have shifted slightly forward, and the mandible has elongated. The resulting "posterior openbite" can make chewing less effective, but it is easy to treat in a manner that also facilitates long-term treatment success. Many dentists have their mandibular advancement patients chew on hard gum or little wedges called morning occlusal guides (MOGs) in order to force the mandible backward into the old bite every morning. However, these "bite return" exercises are unnecessary and counter-productive, because adjusting the bite forward is much easier and better for long term health than trying to reverse the growth that has already occurred or prevent further growth in a functional environment that stimulates it. In fact, an important advantage of using oral appliances for treatment of apnea is that they can reduce dependence on treatment by advancing the resting posture of the mandible and tongue, which get used to being in a forward position.
COSTS - Many different types of mandibular advancement appliances are available from many dentists. We employ a fully adjustable (titratable) high push Herbst appliance. The fee for that appliance along with a soft palate elevator for stage one treatment is $3500. Stages two and three costs depend on circumstances, and they can be waived if you are participating in one of the two ongoing clinical studies to evaluate the effectiveness of the treatment using after before and after home sleep testing.