Oral appliances for the treatment of snoring and obstructive sleep apnea

Abstract

Oral appliances have been used by dentists for several decades to treat snoring and obstructive sleep apnea. Although these devices are regulated by the Food and Drug Administration, most have undergone only sparse clinical testing for efficacy and safety. Most otolaryngologists are not well-versed in their applicability as treatment options. This review summarizes the historical development of oral appliances, the types of available devices, the current literature regarding devices, and pertinent regulatory issues as they relate to the ongoing debate over appliance use and potential misuse.

Oral appliances have been considered as treatment options for upper airway obstruction caused by mandibular deficiency since the early part of this century. 1 In the 1980s dentists and orthodontists teamed up with pulmonologists to explore the use of oral appliances to treat patients with obstructive sleep apnea (OSA), first as nasal continuous positive airway pressure (CPAP) failures, then as primary, nonsurgical treatment alternatives. As it became apparent that many devices were somewhat effective as treatment for OSA, manufacturers of these devices sought Food and Drug Administration (FDA) approval to market these appliances for control of both OSA and snoring. Initial FDA approval was obtained but required patients to obtain prescriptions for these devices. The manufacturers had wanted to secure over-the-counter, nonprescription status. Currently, there are more than 35 different oral appliances on the commercial market for amelioration of either snoring or OSA. 2 Before discussion of the regulatory issues, the efficacy and safety of oral appliances should be addressed. This report will focus on oral appliances alone.

HOW DO ORAL APPLIANCES WORK?

The goal of any oral appliance for the treatment of snoring or OSA is to enlarge the airway or at least reduce the collapsibility between the soft palate and the posterior pharyngeal wall. The 3 general types of devices are discussed below.

Types of Devices

Mandibular positioning (advancing) devices. By attaching to one or both dental arches, the intent is to advance or downwardly rotate the mandible. Most devices require a specialized, individualized design to properly fit the device to the individual. A qualified dental laboratory takes the impressions and fabricates the custom-made device. These are the most popular and useful devices. One manufacturer makes a device of a thermolabile material that is designed to be molded and fitted in the office. See Figs 1 and 2 for examples of these devices.

Tongue-retaining devices. The aim of this design is to secure the tongue by negative pressure into a soft plastic bulb, thereby forcibly holding the tongue anteriorly while sleeping. Although this is an attractive concept, for obvious reasons of comfort and compliance few patients like such devices.

Palatal lifting devices. These devices have not demonstrated efficacy in reducing either snoring or OSA and are not recommended by the Sleep Disorders Dental Society.

The clinical use of an oral appliance for the treatment of OSA or snoring must be addressed in the same fashion as the use of any other medical device. The important parameters for discussion are as follows.

Clinical Use Parameters

Efficacy. What scientific studies have been conducted to determine the usefulness of dental devices? Most studies are case series with before and after comparisons of conditions, some objective and some subjective. There are currently no adequate randomized, controlled studies comparing oral appliances, nasal CPAP, and surgical methods for the elimination or amelioration of snoring and OSA. For the treatment of snoring, several devices have been shown to be very effective by either subjective patient report or by bed partner report. O'Sullivan et al 3 documented decreased laboratory-recorded snore frequency and sound intensity in 51 patients.

Fig 1.

Mandibular positioning device with a screw attachment for fine adjustment.

For the treatment of OSA, Schmidt-Nowara et al 4 published an excellent review article in 1995. They reviewed 20 articles reporting on the effects of several different oral appliances. Using pooled data involving the use of various devices, the authors reported that overall, the apnea-hypopnea index (AHI) decreased from pretreatment levels of 42.6 to 18.8. However, the degree of improvement varied. For example, although 70% of patients had a reduction of 50% in their AHI, 13% had an increase. In addition, although 51% of patients who had pretreatment AHI levels greater than 20 had posttreatment levels less than 10, 39% of patients' levels remained greater than 20 after treatment. They concluded that nasal CPAP was more effective than oral appliances for the treatment of OSA, but oral appliances were better tolerated. However, this conclusion was based on a very short period of observation in which to make a compliance comparison.

In 1996 Menn et al 5 reported perhaps the best study to date on the efficacy of oral appliances. Twenty-nine patients intolerant to nasal CPAP were offered a mandibular repositioning device, with measurement of pretreatment and posttreatment nocturnal polysomnography. Seventy percent of patients decreased their respiratory disturbance index (RDI) by more than 50%, with posttreatment RDI levels less than 20 events per hour. However, a pretreatment RDI greater than 40 was present in 4 of 7 nonresponders. The authors concluded that the device was effective for mild-to-moderate OSA, comparable with most surgical results, but not effective for treatment of severe OSA.

Fig 2.

Mandibular positioning device without fine-adjustment capability.

Patient compliance. Short-term reports range from 50% to 100% for patient compliance. Menn et al 5 noted 70% compliance after 3.4 years of usage. Whereas nasal CPAP seems to be better tolerated than oral appliances for severe OSA, the reverse may be true for patients with mild-or-moderate OSA. 6

Cost. In 1995 Schmidt-Nowara et al 4 estimated that custom-made devices cost approximately $900. Of course, this represents the initial fabrication and fitting alone. Multiple adjustments are often necessary over time.

Adverse effects. Initial problems with use of an oral appliance include excessive salivation and discomfort after awakening from having a repositioning device in the mouth all night. Long-term effects include temporomandibular joint discomfort, occlusive changes (anterior flaring of the mandibular teeth), and periodontal disease. 2 , 7 – 9 Dental devices should not be used for treatment in children and adolescents because of the potential of altered mandibular growth and occlusive changes. In addition, they should not be used in patients with preexisting temporomandibular disease.

REGULATORY ISSUES

Before 1976, the FDA was given little regulatory authority over medical devices. The agency could remove from the market products with exaggerated claims or that were deemed dangerous to patients. In 1976, Congress enacted the Medical Device Amendment to the Food, Drug and Cosmetic Act, requiring the FDA to impose regulatory controls over medical devices depending on the relative risk to the patient. Class I devices have little to no risk. Class II and III devices carry intermediate and significant risks, respectively. Manufacturers may gain entry to the market most easily by “510(k) premarket notification.” 10 They must demonstrate that the new product is “substantially equivalent” to a device that is already on the market. This assumes that the existing device is safe, effective, and reliable. The alternate route is to obtain premarket approval if the new device is not similar to a device already on the market. Most products gained premarket approval under the grandfather clause as 510(k) devices rather than undergoing a more rigorous premarket examination as a new device. Unfortunately, this loophole led to excessive product failures and adverse effects under loose postmarket reporting requirements. This led to the Safe Medical Device Act of 1990 that expanded postmarket device reporting of life-threatening adverse reactions and product failures. However, the key deficiency of this new ruling is the lack of more extensive premarket testing before approval. Therefore, just because a device has the stamp of FDA approval, it is by no means any guarantee of safety or efficacy.

Currently, there are approximately 1800 categories of products labeled as medical devices. Certainly, the task of postmarket surveillance by the FDA is daunting at best and nearly impossible without the enthusiastic compliance of physicians, nurses, and user facilities. The most effective and timely feedback to the FDA comes from individual practitioners.

All oral appliances for the treatment of snoring and OSA are considered Class II devices. Of the approximately 35 current devices for snoring and OSA, all underwent some form of clinical scientific studies to demonstrate safety and effectiveness. However, this may have been on only a handful of patients, without randomization of data, and with scant pretreatment and posttreatment data demonstrating safety and effectiveness. In short, just because an oral appliance is currently in use, it does not connote any degree of long-term effectiveness or safety for a particular device. Postmarket surveillance with diligent reporting to the FDA through MEDWATCH of any product failure or adverse effect is essential to differentiate the safe and effective products from unsafe and ineffective ones.

From November 3–5, 1997, the FDA assembled a panel discussion to make recommendations to the agency regarding regulatory issues for oral appliances. Participating members included physicians and dentists treating snoring and OSA. Presentations were made by sleep-disorder specialists, dental device manufacturers, and consumer groups. The most important charges for the panel were 2-fold:

To ascertain whether these devices could be separated into 2 distinct classes: one for snoring and one for OSA.

To determine whether oral appliances should be Class I or II devices, and if they should be sold over-the-counter (off-the-shelf) or require a prescription under the care of a treating physician or dentist.

After extensive discussion, the panel decided that there exists too great of an overlap between snoring and OSA, even if determined to be considered mild in degree. To allow over-the-counter status for a device to treat snoring but not for OSA would provide too much confusion and potential for self-treatment by patients. With concerns over patient safety overriding the wishes of the industry to sell their products in a less regulated off-the-shelf environment, the panel determined that oral appliances should be Class II devices. Because patients may exacerbate their OSA with device use and may sustain adverse effects without monitoring by a physician or dentist, off-the-shelf status was deemed inappropriate.

Indeed, the 1995 official position of the American Sleep Disorders Association states, “The presence or absence of OSA must be determined before initiating treatment with oral appliances to identify those patients at risk due to complications of sleep apnea and to provide a baseline to establish the effectiveness of subsequent treatment.” 9 Barsh, as president of the Sleep Disorders Dental Society, reminded his colleagues in 1996 that “No longer should a dentist merely accommodate a snorer's request to help stop the nightly cacophony by placing a quick-fix dental appliance; rather, he or she must become part of the team that recognizes and treats snoring as a precursor to a potentially life-endangering disease—OSA.” 2 Clearly, close collaboration between treating medical sleep specialists, surgeons, and dentists apprises patients of all reasonable treatment options and their risks and potential benefits.

The FDA currently classifies all oral appliances for the treatment of snoring or OSA as Class II devices for prescription use only. No device is legally available for over-the-counter patient use. However, because the potential market is enormous, device inventors and manufacturers will likely petition the FDA in the near future to reexamine this regulatory status.

SUMMARY

Oral appliances appear to be effective nonsurgical alternatives for many individuals with either snoring alone or mild OSA. Compliance is at least as good as with nasal CPAP, and probably greater for long-term use. However, they should not be recommended as primary therapy for patients with moderate-to-severe OSA, the group that would benefit the most from nasal CPAP. There is concern over the long-term adverse effects, especially anterior flaring of the mandibular incisors and canine teeth, and the promotion of tem-poromandibular joint disorders.

Patients will need to be fully informed by their treating physicians and dentists about the long-term risks and benefits of surgical and nonsurgical modalities of treatment. Currently, very few sleep-disorder centers combine the talents of medical specialists, otolaryngologists, and dentists to guide patients through this maze of conflicting data and opinion. Cost constraints limit the amount of pretreatment and posttreatment diagnostic testing that is reimbursable to document the effectiveness of one modality versus another. More comprehensive outcome studies will be needed to assess the effectiveness of oral appliances compared with surgical and nonsurgical methods of treatment for snoring and OSA.

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