Dental Oral Appliances and CPAP in Obstructive Sleep Apnea and Snoring

There are several options available to the OSA and/or snoring sufferer (or their bed-partners) ranging from Weight-loss, Positional Therapy, Behavioural Sleep Medicine, Dental Oral Appliances, Continuous Positive Airway Pressure (CPAP), various hard and soft tissue jaw, throat and palate surgeries and some emerging therapies such as chest implants which detect OSA and activate the tongue to act as in a similar way to a Dental Oral Device. 

The Problem 

Snoring and Obstructive Sleep Apnea (OSA) are common sleep disorders resulting from repetitive narrowing and collapsing of the upper airway. Untreated OSA is associated with multiple adverse health outcomes including systemic hypertension, coronary artery disease, stroke, atrial fibrillation, increased motor vehicle accidents, congestive heart failure, daytime sleepiness, decreased quality of life, and increased mortality. 

Snoring is also a significant social problem and contributes to decreased quality of life for bed partners through disrupted sleep. Snoring itself may have a negative health impact, such as increased risk for cardiovascular disease. 

The Common Choices 

Most people with OSA could be successfully treated with either an oral appliance or CPAP to manage their disease, but which one is best? 

The upper airway is like a soft, collapsible hose which, if pressed upon, can close preventing air from passing through it. Some people have more collapsible airways, but frequently it is the tongue falling back into the airway that closes it. This is the reason that most Sleep Disordered Breathing is worse when the sufferer lies on their back (prone). OSA management is focused on keeping this airway open either from the inside (of the tube) or outside it. 

Continuous Positive Airway Pressure (CPAP) 

Continuous Positive Airway Pressure is a therapy whereby a well fitted mask maintains air pressure in the upper airway to be greater than the collapsing outside forces. By doing this it acts as a pneumatic splint and holds the airway open. A CPAP does not ‘breathe for you’ but allows normal breathing through a patent or open airway. 

It was developed by the Australian Physician Colin Sullivan in 1981 after research in London. It has gone through many revisions and is now available as different machines to cover various needs including BiPAP, which refers to Bilevel or two-level Positive Airway Pressure. Like CPAP, this sleep apnea treatment works by sending air through a tube into a mask that fits over the nose. While CPAP generally delivers a single pressure, BiPAP delivers two: an inhale pressure and an exhale pressure. These two pressures are known as inhalation positive airway pressure (IPAP) and exhalation positive airway pressure (EPAP).  

CPAP works well and is efficient and effective for Obstructive Sleep Apnea. It is used for snoring but there’s little evidence that this is appropriate for primary snoring. Alas the compliance rates are not as high as we’d like to see them. Despite the benefits, wear comes at a price for many. Having a mask on or over your face can be claustrophobic or uncomfortable.  

The hose joining the mask to the bedside air pump can also be a nuisance when turning in bed, and the pump is not silent. Its real benefit comes as CPAP pressure can be increased to overcome almost any obstruction, but after a certain pressure (which most won’t need), swallowing air can become a problem. 

Various masks are available from a full-face cover down to a much smaller nasal tube. Individual needs dictate what is prescribed. Fitting and adjusting CPAP is an important part of its success as is training how to wear it and get used to it. The mask and hose requires replacement from time to time. 

Oral Appliance Therapy (OAT) 

For over a hundred years, first responders, doctors and anesthetists have used a technique called the ‘Jaw Thrust’ in which the lower jaw is held forwards to prevent closure of the airway. In 1903, a French Surgeon described the first appliance for this purpose which he first used 30 years later. It was the forerunner of the appliances we use today. 

The most common area to become blocked is immediately behind the tongue. Since the back of the tongue is the front of the airway, anything holding the tongue forwards would be beneficial. 

In 1982, as CPAP was introduced, the first dental appliance became available. It was an elastic bulb which held the tongue forwards and out of the airway called the Tongue Retaining Device (TRD) which can be used by those without teeth. 

The appliance type with which most are familiar is made of two parts (top and bottom) retained by the teeth. This can be a one or two-piece device. As the lower part is attached to the lower teeth, it prevents the tongue from falling back and protects against airway collapse. 

If these parts are joined, it is a one-piece jaw-holding appliance. If separated, the two parts can be adjusted for how far forwards the lower jaw is compared to the upper. This is termed a two-part adjustable appliance and is the preferred choice for that reason. 

These appliances are referred to by many as MADs (Mandibular [lower jaw] advancement Device, or Mandibular Repositioning Device (MRD). While the amount of forward movement can sometimes be very small, the important thing is to hold open the airway. As much as CPAP is a pneumatic stent, an Oral Appliance is a mechanical stent.  

In actual fact, an oral appliance is a bit more involved in providing treatment since Oral Appliance Therapy (OAT) protects against airway collapse as well as tongue stabilization. These are far easier and generally more comfortable than CPAP. However, there is a problem. 

Theoretically, CPAP always works providing the wearer can tolerate it. If it doesn’t work the pressure is increased until it does. An Oral Appliance on the other hand works about 60-70% of the time, so not always. There are ways of predicting likely success but for many, Oral Appliance is the immediate choice regardless. Certainly, when CPAP is refused, Oral Appliance Therapy (OAT) becomes the better choice! 

In recent years, Oral Appliance Therapy (OAT) has become an increasingly common treatment modality for OSA and snoring. Although Continuous Positive Airway Pressure (CPAP) remains the most common treatment for sleep disordered breathing, OAT offers effective therapy for many patients with OSA.  

These devices offer advantages over CPAP because they do not require a source of electricity and are less cumbersome, especially with travel. Oral appliances are well tolerated in most patients, and therapeutic adherence is better than CPAP. 

The clinical use of oral appliances (OAs) for the treatment of snoring and obstructive sleep apnea (OSA) has markedly increased when patients are made aware of their options. 

The American Academy of Sleep medicine reported the following in their most recent positional paper. 

Since 1975, the American Academy of Sleep medicine has accredited and regulated sleep medicine practice in North America. 

Comparing and Contrasting - OAT and CPAP 

Snoring 

There was insufficient evidence to compare the efficacy of OAT to CPAP for the reduction in primary snoring although in some studies where it was similar with the OAT and nasal CPAP. Studies observed that the OAT was superior to CPAP in improving sleep quality among bed partners. More patients in this trial also preferred the OAT over CPAP for long-term treatment of snoring. 

Reducing AHI 

There is moderate evidence that CPAP is more effective than OAT in reducing AHI in OSA. Recently, however, some otolaryngologists (ENT) have been questioning whether the AHI should be the main—and sometimes only—determining factor of treatment effectiveness, or whether other measures such as sleepiness scales, quality of life (QOL) measurements, other ‘arousal indices (RDI) and physiological measurements such as blood pressure should play a more prominent role. 

Oxygen Saturation 

There is moderate evidence that CPAP improves minimum oxygen saturation slightly better than OAT in some people. I would suggest this is an important measurement which can be confirmed by subsequent home sleep tests (HST) regardless of choice of CPAP or OAT. 

Arousal Index 

An arousal represents a shift from deep sleep to lighter sleep. There is conflicting evidence that CPAP reduces the arousal index more than OAT in adult patients with OSA. An arousal is the sudden shift from deeper sleep. 

Oxygen desaturation 

Overall there is low evidence that CPAP reduces the Oxygen Desaturation Index slightly more than OAT in some adult patients with OSA. 

Sleep Architecture (REM v NREM Sleep) 

Studies indicates that neither OAT nor CPAP significantly improve % of REM sleep in adult patients with OSA. 

Sleep efficiency 

Studies found no significant difference between the two therapies in improving sleep efficiency; that is the percentage of time spent asleep while in bed. 

Daytime sleepiness 

OAT appears equivalent to CPAP in reducing subjective daytime sleepiness in adult patients with OSA. 

Quality of life 

Studies indicate that OAT is nearly equivalent to CPAP for improving Quality of Life improvements (QOL) in most adult patients with OSA. 

Hypertension 

While there are studies to show that OAT has only a modest impact on reducing blood 

pressure in adult patients with OSA, they also show OAT as nearly equivalent to CPAP in reducing blood pressure in adult patients with OSA. 

Adherence or compliance 

Perhaps unsurprisingly, the adherence with oral appliances is better overall than with CPAP in adult patients with OSA. 

Assessment of Side Effects 

Side effects, serious enough to cause patients to discontinue use of their oral appliance, are less common than side effects causing adult patients with OSA to discontinue the use of CPAP. 

CPAP or OAT 

CPAP and OAT should both be considered before such an important decision is made. Past studies have shown that adherence plays an important independent role in the effectiveness of a nonpharmacologic multicomponent intervention strategy. Higher levels of adherence resulted in reduced rates of disease. 

It is not a matter of one treatment being “better than the other” but more a matter of which is best suited individually and what defines treatment success for an individual patient with their bed partner.  

OAT and CPAP are the commonest prescribed means of managing OSA. Other options such as surgery exist. Optimal treatment by either is improved with a good nasal airway. Adjunctive intervention such as weight loss, positional therapy and other behavioural treatments should be considered to support either therapy. 

Ask your doctor, dentist or us, the questions you need answers to:

Do I really need something done ?

Why ? Is my problem affecting my body, my health, my mouth and teeth ?

What happens if I don’t do anything ?

What are my benefits if the problem is resolved ?

What are my choices and how much does therapy cost?

How long does it take before I benefit ?

How long do the benefits last ? Do I have to do anything ?

Does it hurt and are there any associated problems ?

Will it work for me, what happens if it doesn’t ?

We can start to put these questions into an understandable perspective for you. “You need to know what you need to know” - and that’s before you start any kind of Medical or Dental care - this is your right. This way, you can make a choice based on what’s right and best for you.

Assistance, interest in the patient and support increases the success of any therapy. 

For more Blogs - please see - www.abettersleep.net - Stephen Bray (2020)