From: ENT Today, December 2011
by Mary Beth Nierengarten
http://www.enttoday.org/details/article/1419957/Obstructive_Sleep_Apnea_Options.html
Treatment for patients with obstructive sleep apnea (OSA) remains challenging given
the low compliance rate for continuous positive airway pressure (CPAP) therapy. Oral
appliances are increasingly as a primary treatment for patients with mild to moderate
sleep apnea or for patients who are unable or unwilling to tolerate the CPAP mask and
machine. These uses are in accordance with the American Academy of Sleep Medicine’s
(AASM) 2006 practice parameters for oral appliance use (Sleep. 2006;29(2):240-243).
Data show improvements in sleepiness and quality of life with these appliances,
although CPAP remains superior in reducing polysomnographic indices of OSA such as
reductions in apnea-hypopnea index (AHI) and oxygen saturation (Intern Med J.
2010;40(2):102-106). Some evidence suggests, however, that oral appliances may confer
comparable AHI and oxygen saturation to CPAP because of their compliance rates. The
growing emergence of oral appliances as an alternative to CPAP has highlighted a
multidisciplinary approach to treatment for sleep apnea.
“The basic issue for me is that sleep apnea is a medical disease, and although a dentist
needs to be involved when using an oral appliance to maintain dental health, a physician
needs to be involved in treating the airway and medical disease,” said B. Tucker
Woodson, MD, professor of otolaryngology and communication sciences at Medical
College of Wisconsin in Milwaukee, Wisc. “The otolaryngologist is ideally positioned
because we understand the airway and we understand dental disease.”
John Remmers, MD, a pulmonologist and professor of internal medicine and physiology
and biophysics at the University of Calgary in Alberta, Canada and one of the inventors
of CPAP, said otolaryngologists may be the physicians most prone to recommending
oral appliances.
“Most of us sleep physicians are pulmonologists and we are comfortable with pressures
and air flows, so CPAP is very intuitive to us,” he said. “Surgeons are different and are
more anatomically oriented, so it is understandable that they may be more open to oral
appliances.”
Oral Appliances
According to Alan A. Lowe, DMD, PhD, there are two kinds of oral appliances: those
that move the jaw forward and tongue-stabilizing devices that hold the tongue forward.
The goal of both types of devices is to expand the upper airway to improve airflow,
thereby preventing the collapse of the pharynx during sleep, said Dr. Lowe, chair of
orthodontics at the University of British Columbia in Vancouver, BC.
Appliances that move the jaw forward are known as mandibular advancement devices
(MADs). To date, most of the research on mandibular advancement has focused on
these devices. MADs prevent the collapse of the upper airway by mechanically
protruding the mandible (Intern Med J. 2010;40(2):102-106). A key issue still to be
resolved, however, is the best way of titrating mandibular advancement to achieve
optimal efficacy and comfort for each patient. The need for proper titration is
highlighted by data that show high response rates, improvements in sleepiness and
cognitive tests, and increases in health-related quality of life in patients fitted to MADs
that are properly titrated (Curr Opin Pulm Med. 2009;15(6):591-596).
“The problem with MADs is that the dentist doesn’t always know who will respond to
MADs or exactly how much protrusion is needed for effective therapy,” Dr. Remmers
said. He added that the adjustments or titrations that are done to get a positive response
are often highly subjective and rely less on precision than guesswork. “This all leads to
the difficulty for the physician in both selecting patients for MADs and providing a
recommendation on how much to adjust the oral appliance to achieve efficacy,” he said.
Tongue-stabilizing devices (TSDs) are not as well studied or used. However, results of a
recent randomized study that compared TSDs to MAS (mandibular advancement splint)
suggest that MAS may remain the preferred device for now based on lower tolerance
associated with TSDs despite comparable efficacy (Sleep. 2009;32(5):648-653).
“In clinical practice, the use of MAS is likely to predominate,” said Peter Cistulli, MD,
head of sleep medicine at the University of Sydney’s Sydney Medical School in Australia.
He added, however, that the development of more tolerable methods of advancing the
tongue may be warranted given a recent study he and his colleagues conducted that
found that the magnitude of upper airway enlargement was greater with TSD than with
MAS (Sleep. 2011;34(4):469-477).
Efficacy of MADs
Several studies have shown the efficacy of MADs for improving snoring, reducing
excessive daytime sleepiness, effecting some improvements in neuropsychological
functioning and modestly reducing blood pressure in patients with OSA (Curr Opin
Pulm Med. 2009;16(6):591-596). Most data show that the effect of these devices on AHI
and oxygen saturation is lower than the effect seen with CPAP, but the better
compliance seen with oral devices may result in comparable outcomes between these
two modes of treatment.
Dr. Lowe emphasized the importance of educating otolaryngologists about the
usefulness of oral appliances and their feasibility as another adjunct to OSA treatment.
“The advantage of an oral appliance is that it is worn more but may be less effective for
oxygenation. The advantage of CPAP is that it is worn less but is more effective for
oxygenation,” he said. “What really matters is how the quality of life for the patient has
changed, and this outcome is pretty comparable between oral devices and CPAP.”
Patient Selection
One overall limitation of the studies on MADs to date has been the quality of the
evidence used to make treatment decisions, which, according to a 2011 review of the
literature commissioned by the Agency for Healthcare Research and Quality (AHRQ), is
only moderate to insufficient (AHRQ Comparative Effectiveness Reviews. 2011;32).
This review emphasizes the critical question facing otolaryngologists trying to decide
whether or not to use an oral appliance: how to identify which patients will benefit the
most from these devices.
Dr. Remmers said the prediction capability regarding which patients will respond to oral
appliances is still lacking. Most physicians, he said, will only consider an oral appliance
for patients who have a respiratory disturbance index of <20, are not obese, have failed
CPAP and have an adequate dentition. “However, research on MADs has shown that
many patients who fall outside of these criteria can be well treated with oral appliances,”
he said.
To date, research on patient selection for MADs has involved looking at anatomical
problems, such as structural narrowing of the pharynx, which may identify patients who
may not be good candidates for an oral appliance. Other data suggest that the use of
nasopharyngoscopy may help identify which patients will respond to MADs. One study
found an association between a reduction in AHI in patients who showed improvement
in upper airway patency with mandibular advancement during a drug-induced sleep
nasopharyngoscopy (Eur J Orthod. 2005;27(6):607-614). In addition, evidence suggests
that performing a nasopharyngoscopy when a patient is awake may be useful in
predicting treatment response to MADs (Eur Respir J. 2010;35(4):836-42).
Other studies are looking at whether removing the obstruction in the airway of a patient
by protruding the mandible during sleep may identify a patient as a good candidate for a
MAD. According to Dr. Remmers, who is studying this approach, two published studies
(Eur Respir J. 2006;27(5):1003-1009; Am J Respir Crit Care Med. 2004;170(4):366370) and data from a recent unpublished study of 65 patients now show unequivocally
that patients can be identified in a sleep study using a device in which the protrusion is
progressively titrated, similar to CPAP titration, until the obstruction is removed. “The
nice feature with this approach is that if you do eliminate the obstruction, you not only
know that patient will respond to MADs but you know exactly how far the mandible
needs to be protruded to achieve this,” he said. The research in this area is expected to
be embodied in a new MAD titration product known as MATRx, due in early 2012
__________________________________________________________________
CLINICAL PROTOCOL FOR TREATING OSA WITH ORAL APPLIANCES
1. Medical assessment by physician or sleep specialist to ensure proper diagnosis,
assessing the presence or absence of obstructive sleep apnea.
2. Overnight polysomnogram or similar test evaluated by physician or sleep
specialist sent to dentist.
3. Complete oral examination that includes both medical and dental histories, along
with dental radiographs, needed for assessment by dentist.
4. Determination of type of oral appliance to use.
5. Appliance is fitted and adjusted to patient after fabrication.
6. Dentist needs to follow up with patient regardless of the type of appliance used.
7. Patient should be referred back to attending physician for assessment of repeat
sleep study to provide an objective measure of the efficacy of the oral appliance.
8. If oral appliance is shown to be effective and is comfortable for the patient,
dentist should schedule a follow-up appointment every six months for the first
two years to monitor effectiveness, comfort and side effects such as occlusion.
9. Regular follow-up appointments, at least once a year thereafter, to monitor
outcomes and appliance wear and tear.
Source: Almeida FR, Lowe AA. Principles of oral appliance therapy for the
management of snoring and sleep disordered breathing. Oral Maxillofac Surg Clin
North Am. 2009;21(4):413-420.
__________________________________________________________________
Issues to Consider
Along with identifying patients for whom oral appliances may work best, other issues
that may need consideration include the major side effect of these appliances, tooth
movement or occlusal changes.
Dr. Lowe considers this a small disadvantage compared to the benefit of controlled OSA.
“The longer we are in the field, the more we are accepting that [tooth movement] as a
side effect and we work around it because compared to decreased oxygen to the heart, it
is a pretty minor thing,” he said.
Finally, an important role for oral appliances may be in their use in conjunction with
CPAP. “CPAP and oral appliances can be used interchangeably,” said Fernanda Ribeiro
de Almeida, DDS, PhD, assistant professor of dentistry at the University of British
Columbia in Vancouver, BC, Canada. She said many patients who use CPAP routinely
may be more compliant overall with treatment if they use oral appliances when CPAP is
less convenient, such as on the weekends or when travelling.
Disclosures: Dr. Cistulli has contributed to the development of the mandibular
advancement splint. He has also consulted for and has been on the advisory board for
oral device maker SomnoMed and has financial interest in the company. Dr. Remmers
receives royalties from AutoCPAP and is part owner of Zephyr, the company that
manufactures MATRx a test for selecting patients for oral appliance therapy. Drs.
Fernanda and Tucker report no relevant financial ties.
Cortesia de: Tomás Seif R, Odontólogo, Master of Science, Director Clínico de NoRonques+
Avenida Principal Urb. Chuao, Edificio Centro de Especialidades Odontológicas.
Unidad dental de ronquido y apnea del sueño. Planta baja
Caracas 1061, Venezuela
Tlfs / fax: 0212- 525.20.20 / 993.56.07 / 993.37.01
www.noronquesmas.com - info@noronquesmas.com - www.ceo.com.ve