Oral Appliances for the Treatment of Patients With Obstructive Sleep Apnea

Although the first reported case of oral appliance use was by Pierre Robin in 1934,^1,2 recognition of the effectiveness of these devices in treating sleep-disordered breathing did not gain momentum until the early 1980s. As oral appliances have evolved and dentists have gained expertise in their use, these devices have become an important part of the management of patients with sleep-disordered breathing. At present, oral appliances are recommended as second-line management for patients with obstructive sleep apnea (OSA) who have mild to moderate disease and who prefer an oral appliance or are intolerant of continuous positive airway pressure (CPAP) therapy.^3,4

The American Academy of Sleep Medicine’s practice parameters for oral appliance management of OSA notes that oral appliances are indicated in patients with mild to moderate OSA who prefer the use of an oral appliance to CPAP.

Oral appliances are also recommended for those patients who do not respond to CPAP, who are not appropriate candidates for CPAP, or who fail treatment attempts with CPAP.⁴ Oral appliances should be fitted by qualified dentists who are trained and have experience in the care of oral health. These appliances improve sleep-disordered breathing and subjective measures of sleepiness when compared with no treatment or placebo.^5,6 Although CPAP is more effective at improving sleep-disordered breathing than are oral appliances, oral appliances produce significant improvements in measures of sleep-disordered breathing, blood pressure, and quality of life.^5-7 Of note, oral appliances outperformed upper airway surgery in a head-to-head trial.⁸

Oral appliances have been identified by several names, including mandibular repositioning appliances (MRAs), mandibular repositioning devices (MRDs), mandibular advancement splints (MASs), mandibular advancement devices (MADs), and tongue repositioning or tongue retaining devices (TRDs).

These appliances are divided into two categories: those that advance the mandible (MRA, MAS, MRD, and MADs) and those that reposition and retain the tongue in a forward position (TRDs). Since TRDs are not FDA-approved and have not been extensively studied, they will not be discussed further here.

For clarity, the term “mandibular repositioning appliances” will be used in this discussion. MRAs are viewed by the US Food and Drug Administration as class 2 medical devices. MRAs are typically made in two pieces (upper and lower) and then connected. They can be rigid (monobloc) or adjustable (duobloc), with the upper and lower portions attached by a hook or screw assembly or by elastic bands. They are most often made of acrylic resin and well adapted to the teeth for retention purposes.

Adjustable devices are more popular and effective, as they can incrementally advance the lower jaw forward and downward. Many adjustable devices allow for lateral movements of the mandible. This attribute is especially beneficial for patients with OSA who experience bruxism. Devices made of thermoplastic (also known as “boil and bite”) are not considered custom-made appliances and do not perform as well.⁹

How MRAs Work
MRAs work by moving the mandible down and forward, which opens the posterior airspace and pulls the tongue forward. Mandibular protrusion by means of an MRA results in a significant increase in the airway diameter, especially in the oropharyngeal cross-sectional area, in both obese and nonobese subjects.^5,10,11 This increase in airway caliber results in increased airflow, reduced snoring, and improved sleep-disordered breathing.

Side Effects and Contraindications
Side effects of MRAs include temporomandibular joint and facial pain or discomfort, temporomandibular joint noises, minor tooth movement, changes in occlusion, and skeletal changes, including increased facial height.^5,11,12

Although oral appliances can be used successfully in patients who grind their teeth, use of an MRA that allows for adequate lateral and anterior-posterior movement may be less likely to exacerbate temporomandibular joint pain.

Most side effects that with MRAs are minor and temporary and do not significantly affect appliance use.^5,11,12

Contraindications to the use of MRAs include severe temporomandibular joint pain, insufficient teeth to retain the appliance during usage (eight teeth is probably the minimum), teeth that are compromised by periodontal disease, and a limited mandibular range of motion.¹⁰

Oral Appliance Management of the Patient With OSA
Oral appliances are an important part of the armamentarium for OSA management. Optimal management of patients with sleep-disordered breathing requires collaboration between a sleep physician and a dentist who is well trained in dental sleep medicine.

When evaluating a patient with OSA for an oral appliance, the dentist does a dental sleep workup, which includes a thorough review of the medical history, an evaluation of the nasal cavity, and an in-depth evaluation of the oral cavity and the temporomandibular joints and associated structures. Impressions for study and working models are taken, as well as a panoramic radiograph or other imaging.

After an appliance is inserted, the dentist needs to follow up with the patient on a weekly or biweekly basis to assess if the appliance is having an effect. If the appliance is not having an effect, it is then titrated (by moving the mandibular, or lower unit, forward) until it does or it is determined that it is not going to work.

A maximum titration of 75% of the patient’s protrusion is generally considered the endpoint for titration. A repeat sleep study is recommended to assess the efficacy of the appliance, once it has been titrated,⁴ but it is the author’s experience that this happens rarely.

Once efficacy of the appliance is confirmed, continued follow-up by the dentist is essential in order to assess tooth movement and other side effects. The patient is generally seen every 6 months for the first year and at least once a year thereafter.

The ACCP Sleep Medicine NetWork collaborated with the American Academy of Orofacial Pain to produce a printable patient education brochure about oral appliances. This is available on the ACCP Web site at www.accpstorage.org/newOrganization/patients/oralAppliances.pdf.

References

1. Cartwright RD, Samelson CF. The effects of a nonsurgical treatment for obstructive sleep apnea: the tongueretaining device. JAMA. 1982;248(6): 705-709.
2. Krishnan V, Collop NA, Scherr SC. An evaluation of a titration strategy for prescription of oral appliances for sleep apnea. Chest. 2008;133(5):1135-1140.
3. Hoekema A, Stegenga B, Wijikstr PJ, vander Hoeven JH, Meinesz AF, de Bont LGM. Obstructive sleep apnea therapy. J Dent Res. 2008; 87(9):882-887.
4. Kusida CA, Morgenthaler TI, Littner MR, et al. Practice parameters for the treatment of snoring and obstructive sleep apnea with oral appliances and update for 2005. Sleep. 2006; 29(2):240-243.
5. Ferguson KA, Cartwright R, Rogers R, Schmidt-Nowara W. Oral appliances for snoring and obstructive sleep apnea: a review. Sleep. 2006: 29(2):244-262.
6. Otsuka R, Ribeiro de Almeida F, Lowe AA, Linden W, Ryan F. The effect of oral appliance therapy on blood pressure in patients with obstructive sleep apnea. Sleep Breath. 2006;10(1):29-36.
7. Lam B, Sam K, Mok WY, et al. Randomised study of three non-surgical treatments in mild to moderate obstructive sleep apnoea. Thorax. 2007;62(4):354-359.
8. Walker-Engstrom ML, Tegelberg A, Wilhelmsson B, Ringqvist I. 4-year follow- up of treatment with dental appliance or uvulopalatopharyngoplasty in patients with obstructive sleep apnea: a randomized study. Chest. 2002; 121(3):739-746.
9. Vanderveken OM, Devolder A, Marklund M, et al. Comparison of a custom-made appliance and a thermoplastic oral appliance for the treatment of mild sleep apnea. Am J Respir Crit Care Med. 2008;178(2):197-202.
10. Hiyama S, Tsuiki S, Ono T, Kuroda T, Ohyama K. Effects of mandibular advancement on supine airway size in normal subjects during sleep. Sleep. 2003;26(4):440-445.
11. Pantin CC, Hillman DR, Tennant M. Dental side effects of an oral device to treat snoring and obstructive sleep apnea. Sleep. 1999;22(2):237-240.
12. Marklund M, Stenlund H, Franklin KA. Mandibular advancement devices in 630 men and women with obstructive sleep apnea and snoring: tolerability and predictors of treatment success. Chest. 2004;125(4):1270-1278.

Dr Elmer A. Villalon, DMD
Orofacial Pain and Dental Sleep Medicine
Pueblo, CO

Dr Barbara Phillips, MSPH, FCCP
Professor, Division of Pulmonary, Critical Care and Sleep Medicine
University of Kentucky College of Medicine
Lexington, KY