Evaluation of the Patient

Each candidate for an OA should be examined by a qualified dentist to determine whether an OA is feasible and safe from a dental standpoint. The dental examination should focus on the temporomandibular joint (TMJ), evidence or history of bruxism, quality of dental occlusion, the presence of significant periodontal disease, overall dental health, and protrusive ability. Cephalometrics or dental radiographs may be indicated.¹⁰ The patient’s occlusion type should be noted. Three classes (types) of skeletal occlusions are illustrated in Figure 20–5. One might expect that patients with mandibular deficiency (retrognathia) would benefit the most from an OA but the amount of improvement is somewhat unpredictable. The location of airway occlusion during sleep might also be expected to predict the response to OA treatment. Patients with occlusion mainly in the retroglossal area rather than the retropalatal area might be expected to improve the most with a MRA. However, in one study, some patients with upper airway occlusion mainly in the velopharynx also improved with MRA treatment.¹¹

Exclusions and Contraindications

Patients must have a minimal amount of healthy teeth for an MRA. A minimum of 6 to 10 teeth in each arch is needed.1,5 However, treatment with dental implants can permit future MRA treatment in patients with insufficient dentition at the time of evaluation. Patients must be able to open the jaw adequately for OA insertion and must have the ability to voluntarily protrude the mandible. Moderate to severe TMJ disease or inadequate protrusive ability are contraindications. Mild TMJ dysfunction may actually improve with the jaw positioned anteriorly during sleep. Moderate to severe bruxism is also a contraindication in most cases. Bruxism during sleep can actually damage some types of OAs. However, bruxism in some patients improves with adequate treatment of OSA. An experienced dental practitioner should evaluate patients with bruxism for suitability for an OA. A history of bruxism may also alter the choice of the type of OA used. Of note, edentulous patients can be treated with a TRD/TSD.

Mechanism of Action of OAs

OAs are believed to work by increasing upper airway size. TRDs/TSDs move the tongue forward. MRAs move the tongue and mandible forward, increasing the posterior airspace. By stabilizing the mandibular position, MRAs resist the downward rotation of the mandible with sleep and the accompanying retrusion of the mandible. They may also tense palatal muscles. Some studies have found an increase in upper airway muscle tone with an MRA in place.¹² As noted previously, patients with airway closure mainly in the velopharynx may also respond to OA treatment. In agreement with this finding, a study of the effect of an MRA on upper airway size during wakefulness using fiberoptic endoscopy found the most significant increase in airway size was at the velopharynx.¹³ Another study of videofluoroscopy during sleep found increases in both the retroglossal and the retropalatal airway size during sleep with an MRA in place.¹⁴

Effectiveness

A number of studies (some controlled) have demonstrated that OA devices are effective in reducing the apnea-hypopnea index (AHI) in mild, moderate, and severe OSA.1,2 However, because OAs are less effective than continuous positive airway pressure (CPAP) in reducing the AHI to less than 10/hr, CPAP is considered the treatment of choice for moderate to severe OSA. American Academy of Sleep Medicine (AASM) practice parameters² state that OAs are indicated for treatment of mild and moderate OSA as well as snoring. The practice parameters also state that OAs can be used in severe OSA, although generally considered a third-line treatment after positive airway pressure (PAP) and surgery. A summary of effectiveness in a systematic review of OAs published in 2006 is listed in Table 20–1. Although results differed considerably between studies, OA treatment was found to be successful in about 50% of patients with mild to moderate OSA (using an AHI < 10/hr as the definition of success).¹ Of note, some patients with severe OSA can have an impressive reduction in the AHI, although rarely to a value less than 10/hr (Fig. 20–6).

Studies have also documented that OA treatment improves both subjective and objective sleepiness. Using a controlled cross-over design (OA without protrusion as control), Gotsopoulos and coworkers¹⁵ found significant improvement in the subjective sleepiness (Epworth Sleepiness Scale decreased from 9 to 7) and objective sleepiness as assessed by the multiple sleep latency test (mean sleep latency increased from 9.1 to 10.3 min).

Factors Predicting Effectiveness

Four variables appear to contribute to the degree of effectiveness of OA treatment of OSA.1,16,17 These include (1) the severity of the OSA, (2) amount of protrusion by the MRA, (3) the presence or absence of positional sleep apnea, and (4) the body mass index (BMI).¹ The degree of protrusion of the mandible with MRAs varies typically from 6 to 10 mm or from 50% to 75% of the maximum the patient can voluntarily protrude the mandible on request. One study using the same OA with different protrusions found a reduced AHI with greater protrusion.¹⁶ Positional OSA defined as a supine AHI > 2 × lateral AHI predicts that OA will be more effective^1,17 (Fig. 20–7). OA treatment also is more effective in mild to moderate OSA (better chance of treatment AHI falling in acceptable range). They also appear to be more effective in the less obese patient.

Devices

The TSD is manufactured in three prefabricated sizes (small, medium, and large), whereas TRDs are custom-fitted to each patient. The patient inserts the tongue into the device and gently pumps the bulb to apply suction. Once the tongue is inserted, the bulb is released and the tongue is held forward by suction. One study found the TSD to significantly reduce the AHI, although not quite as well as an MRA.⁹ In addition, the TSD had a lower compliance rate and was more likely to come out during the night. However, the TSD (see Fig. 20–1) may be an affordable alternative for some patients. Purchase of a TSD requires a prescription from a doctor or dentist (approximate price range is $125–$180).

Some ideal attributes for an MRA are listed in Table 20–2. The ideal device has coverage of both arches and is adjustable (protrusion can be changed). A recent study compared a custom-made and thermoplastic OA for the treatment of mild OSA. The custom-made device was more effective.¹⁸ However, custom-made devices are typically much more expensive. OAs are now viewed by the U.S. Food and Drug Administration (FDA) as class 2 medical devices and, as such, must adhere to more detailed standards with special controls.¹⁹ A short list of commonly used devices is presented in Table 20–3. A more extensive list is available in Reference 5. A list of FDA-approved devices can be found at http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfPMN/pmn.cfm

Titration/Adjustment of OAs

After OAs are fabricated, they are usually adjusted by the dentist taking care of the patient for fit and comfort. Patients are then instructed to slowly increase mandibular protrusion until symptoms improve (cessation of snoring and improvement in sleep quality) or until either the maximum protrusion is reached or further advances are not tolerated. In one study, patients were studied during polysomnography (PSG) and a remotely controlled mandibular appliance was advanced until respiratory events were controlled or until further advances were not tolerated.²⁰ The results of the PSG OA titration were highly predictive of the effectiveness of chronic OA treatment with a permanent device. In another study, patients were allowed to adjust their devices at home.²¹ During a PSG if persistent events were noted, further adjustment during the PSG was performed by protocol (increased protrusion in 1-mm increments). Of the patients completing the protocol, 55% were successfully treated (AHI < 10/hr) after home titration. A total of 64.9% of patients were successfully treated overall. Thus, some patients will likely need further adjustments either during or after a PSG documenting the efficacy of OA treatment.

Adherence to OA Treatment

Studies of adherence to OA treatment have almost always relied on patient report. There is a single report of the use of a temperature-sensitive embedded monitor to objectively determine OA use.¹³ OA adherence rates tend to decrease with the duration of use. One study reported 60% adherence at 1 year and 48% at 2 years.²² Another study reported adherence dropped from 82% to 62% over 4 years.²³ The reasons for discontinuing OA included side effects, complications, and lack of efficacy. In a questionnaire study of OA patients 5 years after starting treatment, 64% of respondents were using the OA. Of these, 93% were using the OA more than 4 nights/wk. Of those stopping OA treatment, the causes were discomfort (44%), little or no effect (34%), and the patient changing to CPAP treatment (23%).²⁴ In two cross-over studies of CPAP, adherence to OA was equal to or better than to CPAP.^25,26

Effectiveness Compared with Other Treatments

A number of studies have compared OA and CPAP (Table 20–4).²⁵–³¹ They show that OAs are not as effective as CPAP but are effective in a significant proportion of patients (19–67%) (Fig. 20–8).¹ In some studies listed in Table 20–4, a significant proportion of patients preferred the OA to CPAP. In some studies, improvement in daytime sleepiness was similar with both OA and CPAP treatment even if the AHI was higher with OA than with CPAP. In the study by Barnes and colleagues²⁷ using a cross-over design, 28% preferred CPAP, 41% preferred the OA, and 31% preferred placebo (a tablet). In a study by Ferguson and associates,²⁵ the compliance to an OA and CPAP were similar but patient satisfaction was better with an OA.

OA Treatment Guidelines

The AASM practice parameters for the OA treatment of patients with snoring and OSA² are listed in Appendix 20–1. The guidelines are summarized in Boxes 20–1 and 20–2. The presence or absence of OSA must be determined before OA treatment. It is important to determine whether OSA or snoring is being treated. If OSA is present, the severity has implications for treatment selection and the probability of success with OA. The OA should be fitted by a qualified dental professional. The treatment goals for snoring are to reduce noise to an acceptable level. For OSA, treatment goals are to reduce the AHI, improve oxygenation, and improve sleep quality. OAs are indicated for primary snoring that does not respond to simple measures such as weight loss, lateral position, and treatment of nasal congestion. OAs are also indicated for mild to moderate OSA. It is acknowledged that CPAP may be more effective. CPAP rather than OA should be the first treatment for severe OSA. If CPAP is not accepted, upper airway surgery or an OA should be considered. Upper airway surgery may also supersede use of OA in patients for whom surgery is predicted to be highly effective. In patients with severe OSA who decline CPAP or surgery, a trial of OA may be reasonable. Another indication for OA would be patients who had failed surgery and do not want CPAP or further surgery.

Adjustment of OA is usually preformed over days to weeks with progressive protrusion until obvious apnea and snoring have ceased or the limit of the device or patient tolerance is reached. A study can then be performed to assess efficacy. As noted in a later section, documentation of efficacy with some type of sleep study is indicated for any level of OSA severity. For snoring alone, subjective improvement may suffice.

Follow-up

The practice parameters do not mandate repeat sleep testing for OA treatment of snoring. For all severities of OSA, repeat sleep testing with the patient wearing the OA is indicated to document effectiveness (see Box 20–2).² The practice parameters state either PSG or an attended type 3 cardiopulmonary test is acceptable to assess the efficacy of OA treatment. Recent clinical guidelines for portable monitoring (PM) also state that unattended PM “may be indicated” to determine the adequacy of non-PAP treatment.³² In fact, either unattended cardiopulmonary monitoring or attended PSG is usually used to determine the effectiveness of OA treatment. Follow-up visits with the dentist who fabricated the OA device are also indicated every 6 months, then yearly. This is to ensure side effects are not significant and the amount of protrusion is optimized. Follow-up with the clinician directing sleep apnea treatment is also indicated to be certain OSA symptoms are controlled and do not recur. If symptoms return while the patient is using the OA, repeat sleep testing with OA in place is indicated.

Centers for Medicaid and Medicare Services Coverage of OA Treatment

The Centers for Medicaid and Medicare Services (CMS) has recognized certain types of OAs as reasonable and necessary for treatment of OSA. The criteria for reimbursement have been published in the form of local carrier determinations (LCDs) by Durable Medical Administrative Contractors (DMACs). An excerpt from one LCD is listed in Appendix 20–2. Only custom-fabricated mandibular advancement OA (E0486) devices are covered. Coverage requires a face-to-face clinical evaluation prior to a Medicare-covered sleep test. The patient must meet one of the following criteria: (1) AHI ≥ 15/hr or respiratory disturbance index (RDI; events/hr of monitoring time using a home sleep test) ≥ 15/hr or a minimum of 30 events, (2) AHI (RDI) values 5 to ≤ 14 with certain symptoms or disorders (see Appendix 20–2), AHI > 30 or RDI > 30 if the patient cannot tolerate a PAP device or if the treating physician feels PAP treatment is contraindicated. Note that testing for diagnosis cannot be performed by the person or organization supplying the OA. The OA device must be ordered by the treating physician following review of the report of the sleep test. The device is provided and billed for/by a licensed dentist (DDS or DMD). Custom-fabricated devices that work by positioning of the tongue (E1399) or a prefabricated OA (E0485) are not covered.

Side Effects and Complications

The available research suggests that side effects and complications (Box 20–3) may be grouped as follows: (1) minor and temporary side effects and (2) moderate to severe and continuous side effects.

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Obstructive Sleep Apnea Treatment Overview and Medical Treatments The Restless Leg Syndrome, Periodic Limb Movements in Sleep, and the Periodic Limb Movement Disorder Biocalibration, Artifacts, and Common Variants of Sleep Monitoring Respiration—Event Definitions and Examples Central Sleep Apnea and Hypoventilation Syndromes Cardiac Monitoring during Polysomnography

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