Improved Oral Appliance Treatment For Sleep Apnea

SUMMARY

Obstructive sleep apnea (OSA) occurs when people choke on their tongues during sleep.  In millions of people, these airway blockages occur frequently enough and for long enough to become a serious health problem, but treatment is problemmatic.  CPAP is usually effective, but most people hate it.  Dentists make a variety of oral appliances to treat sleep apnea by protruding the lower jawbone (advancing the mandible), and patients find them much more tolerable than CPAP; but numerous studies show that their success rates never exceed about 50%, because the lower jawbone is only loosely attached to the tongue and therefore has limited ability to keep it from dropping back into the throat. To make oral appliances more effective in these cases, Dr. Summer has developed a new tongue holding device that is made of dental acrylic so it can be added to almost any jaw protrusion appliance in order to grasp the tongue between thousands of forward-slanted plastic bristles and hold it forward together with the lower jawbone.  The device also includes an adjustable tongue base controller and an optional soft palate elevator that can be used to clear obstructions between the tongue base and the soft palate.  By protecting airway passage through the whole pharynx, such a multi-level oral appliance approach is likely to become a first line treatment for sleep apnea.

PATHOPHYSIOLOGY OF SLEEP APNEA

Obstructive Sleep Apnea (OSA) occurs during sleep when the tongue gets sucked back into the throat during an inspiration and creates a plug that prevents all breathing until the resultant decrease of oxygen levels and increase of carbon dioxide levels trigger an adrenalin release which causes a gasp that temporarily restores the airway. The blockage may include some loose tissues from the soft palate or lateral tonsillar walls, but the tongue is the only structure in the area large enough and rigid enough to obstruct the airway.  In millions of older people, these recurrent intermittent airway obstructions last long enough and occur frequently enough to pose a serious health problem.  Almost half of those over the age of 60 suffer from OSA.  

CURRENT MEDICAL TREATMENT

Studies using imaging to try and locate the pharyngeal airway obstruction in OSA have found that it is too variable to provide a basis for targeted treatment.  Surgery is only predictably effective if it is performed in multiple areas (multi-level surgery).  CPAP (continuous positive airway pressure) is usually effective, because it balloons out the whole pharynx, but most people hate it.   A large number of simple treatments such as nasal strips, chin straps, nasal expiratory positive airway pressure valves (Provent or Zyppah), and various over the counter mouth appliances are aggressively marketed but only occasionally effective.  

CURRENT DENTAL (ORAL APPLIANCE) TREATMENT

Dentists make a variety of oral appliances to treat sleep apnea.  The vast majority of them work by protruding (moving forward) the lower jawbone and thereby making a space into which the tongue can protrude to allow airway passage behind it.  However, numerous studies have shown that jaw protrusion is never more than about 50% effective at eliminating the problem, because creating a space in front of the tongue cannot move the tongue forward into that space. The lower jawbone and the tongue are only attached by muscles, which lose tonus during sleep.  Consequently even extreme jaw protrusion can’t always prevent the tongue from falling back and obstructing the pharynx - it just has a little further to fall.  The tongue stabilizing device (TSD) is a silicone rubber oral appliance that directly protrudes the tongue by grasping its tip in a suction bulb and holding it all the way out in front of the lips; but it only controls the tongue tip, while the choking occurs at the tongue base, so it is not always effective. In addition, the extreme tongue protrusion it requires is difficult for most people to tolerate.  Tongue rear depressors and soft palate elevators have also shown some success, but they are rarely effective when used alone.   

COMBINING ORAL APPLIANCE TREATMENTS

Combining all of these treatment modalities offers obvious advantages in both effectiveness and comfort, because their actions are highly synergistic. The lower jawbone provides the base of operation for the tongue (which has no bone of its own), so lower jawbone protrusion and tongue protrusion are mutually supportive.  Protruding the tongue makes its rear portion more accessible for mechanics that reach behind it so they can push it down and forward away from obstruction with the soft palate, which is more effective when combined with a soft palate elevator that draws the end of the soft palate upward and forward away from obstruction with the tongue base.  However combining all of these treatment modalities has not been possible previously, because the mechanical components needed for each modality have not been compatible.  For example, the silicone rubber of the TRD cannot be easily attached to dental acrylic. To solve this problem, Dr. Summer has developed a new tongue holding device that is entirely made of dental acrylic so it can be added to almost any jaw protrusion appliance in order to hold the tongue forward together with the lower jawbone.  The new device also includes an adjustable tongue base controller and an optional soft palate elevator.  

Clinically the modalities are added to an oral appliance one at a time with home sleep testing after the addition of each modality to find out if the oral appliance is effective in its present form with the modalities it has.  We use a home sleep test that records data over multiple nights, because people rarely sleep normally the first night they wear any new device, and because, even under the best of circumstances, there is a 15% variability in recordings from different nights.  If the appliance is to provide a long term solution, it must not just reduce but substantially eliminate your sleep apnea.  If your oral appliance simply reduces the frequency of apnea events, it will not provide a long term solution, because each event continues to stretch the pharyngeal tissues and thereby make the airway more susceptible to obstruction. 

Treatment begins with a jaw protrusion appliance that is fully titrated - adjusted forward as far as you can tolerate.  If that does not eliminate your apnea, the tongue holding device is added to hold your tongue forward with your lower jawbone.  Then, if that combination is still not effective, the position of the tongue base is adjusted and the soft palate elevator is added.   Following this protocol, your oral appliance will contain only the modalities you need to solve your problem.  The protocol is described in more detail below.

STAGE ONE, JAW PROTRUSION 

The first stage of multilevel treatment is titrated jaw protrusion, because that modality is effective in about half of OSA patients.  There are dozens of jaw protrusion appliances being marketed by dentists for this purpose.  TITRATING your jaw protrusion appliance means gradually adjusting it further forward until you get it as far forward as you can tolerate without discomfort.  Titration of jaw protrusion appliances has been shown in multiple studies to increase their effectiveness. 

The appliance that we normally use to initiate treatment is a telescopic appliance that we have modified for adults with OSA.  Telescopic appliances have a long history of proven effectiveness in treatment for OSA.  However the commonly used Herbst and SUAD telescopic components were designed more than half a century ago for orthodontic bite jumping in children, and they are unnecessarily bulky and restrictive. We have redesigned them by flattening the telescopic components to better fit the buccal vestibule (the space between the teeth and the cheeks) for comfort, allowing a free range of motion laterally for TMJ health, and making them micro-adjustable by the patient over a range of ½” without special tools for the titration process, explained below. 

STAGE TWO, ADDING TONGUE PROTRUSION

If follow-up testing shows that you still have OSA after titrating your jaw protrusion appliance, stage two treatment begins with adding a tongue holding device to the jaw protrusion appliance in order to hold the tongue forward together with the lower jawbone. The tongue holding device grasps the tongue between upper and lower tongue gripping surfaces, each containing thousands of miniature forward-slanted bristles that act like directional velcro.  The bristles on the upper tongue gripping surface are sized to fit between each of the little papillae that cover the top of the tongue.  The bristles on the lower tongue gripping surface, which engage the more sensitive mucous membrane on the underside of the tongue, are much smaller and feel like a cat's tongue.  Because of the 45 degree angle of all the bristles, your tongue can easily slide forward into the space between the tongue gripping surfaces, but it cannot slide backward out of that space (shown below right) without opening widely enough to release the tongue.

Wide opening releases the tongue, because the force that grips the tongue is provided by a trans-palatal orthodontic elastic (dashed lines) which pushes the upper tongue gripping surface down into the tongue only until the middle of the elastic reaches the same plane as the ends of the elastic. Any further mouth opening (bottom figure) separates the tongue from the tongue gripping surfaces and thereby releases the tongue, as shown below. 

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It doesn't take long to get used to tongue protrusion that simply holds the tongue forward together with its only bone, the lower jawbone.  Usually follow-up home sleep testing is performed within a week or two after adding the tongue holding device.

STAGE THREE - CLEARING THE UPPER PHARYNX

If another multi-night home sleep test shows that you still have OSA in spite of tongue and lower jawbone protrusion to clear the lower pharynx, your airway is blocked in the upper pharynx (the nasopharynx) where the soft palate and other loose tissues get sucked into the space between the tongue base and the back wall of the pharynx, as shown below. 

  

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In these cases, to restore airway passage in the upper pharynx, the tongue base controllers at the back of the upper tongue gripping surfaces are adjusted to push the tongue base further down and forward away from the area of obstruction with the soft palate while a soft palate elevator is added to draw the back end of the soft palate upward and forward away from the area of obstruction with the tongue base.  Between these tissues moving away from each other a space is produced for airway passage.

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 MOUTHBREATHING

Obligate mouthbreathers have a nasal airway that is too small to allow adequate airway flow.  Their lips are always slightly parted to allow an oral airway.   Many people become obligate mouthbreathers occasionally due to rhinitis or allergies.  These people need an oral appliance that permits mouthbreathing.  The new tongue holding device permits mouthbreathing, because the upper tongue gripping surface descends with the lower jawbone when the mouth is part way open and thereby creates an oral airway passage just under the hard palate.

Some obligate mouthbreathers can be converted to nasal breathing by expanding the palate.  The process can be performed gradually in adults without significant discomfort, and a change from oral to nasal breathing yields major health benefits.  Expanding the palate can probably do a little to help relieve some cases of OSA by creating space for the tongue to rest further forward and upward, especially if the expansion is performed early in life so it can affect subsequent facial growth; but the effect of a palatal expander (including the DNA appliance) on OSA in adults is likely to be minimal, because the airway obstruction in OSA occurs in the throat, not in the nasal cavity. 

Habitual mouthbreathers have developed a habit of holding the mouth open and breathing through it in spite of an adequate nasal airway passage.  They can often be converted back to nosebreathing by holding the mouth closed with various mechanical devices, including chin straps, head straps, thick foam cervical collars, or incorporating interarch elastics into a dual arch oral appliance that is made for sleep apnea and fits the teeth tightly enough to resist being pulled off by the weight of the lower jawbone.  

COST OF TREATMENT

Our fee for stage one treatment, jaw protrusion with the improved telescopic appliance, is  $1900.  The cost for adding THDs to jaw protrusion appliances that were made elsewhere to treat OSA and were found tolerable but ineffective during 2018 is $1200.  To be eligable, patients must have an intact Herbst, Somnomed, EMA, or Oasys appliance, moderate or severe OSA while wearing the appliance, and the willingness to wear a home sleep testing device for three consecutive nights before and after adding the tongue holding device.