Oral Appliance Year in Review
by Sheri Katz, DDS, American Board of Dental Sleep Medicine
Indications for the use of oral appliance therapy (OAT) in the management of obstructive sleep apnea (OSA) have been increasing, along with a growing body of research and the resultant patient-centered protocols in recent years. In 1995, the American Sleep Disorders Association and Sleep Research Society published “Oral Appliances for the Treatment of Snoring and Obstructive Sleep Apnea: A Review.”1 The project referenced 21 publications based solely on case studies, describing a total of 320 patients. Ten years later, for the update paper of 2005, “Oral Appliances for Snoring and Obstructive Sleep Apnea: A Review,” 15 randomized control trials were referenced.2 The American Academy of Sleep Medicine (AASM) developed the current practice parameters for the Treatment of Snoring and Obstructive Sleep Apnea with Oral Appliances from this review.
Currently, a joint task force, charged by the AASM and American Academy of Dental Sleep Medicine (AADSM), is reviewing the last 10 years of the literature in order to develop an updated practice parameter paper. Approximately 34 randomized control trials are being utilized for this project.
The amount of literature and the scope of medicine that the research has covered is giving sleep medicine practitioners increased confidence in the use of oral appliance therapy to treat OSA. Over the past year, oral appliance research in the areas of health outcomes, side effects, and compliance has broadened the understanding not only of the rate of use with the therapy but also of how use influences areas such as blood pressure, temporomandibular disorders, and occlusal changes. Recent research by Andren, Iftikhar, Phillips, Cohen-Levy, Doff, Perez, and Vanderveken has added to this body of evidence over the past year.
Effects of treatment with oral appliance on 24-hour blood pressure in patients with obstructive sleep apnea and hypertension: a randomized clinical trial3
The object of this pilot study was to evaluate the potential effects of oral appliance therapy on blood pressure. A total of 72 patients with obstructive sleep apnea were randomly assigned to an active group (an oral appliance with mandibular advancement) or a control group (an oral appliance with no mandibular advancement). At baseline and, then again, after 3 months, patients had sleep studies and 24-hour blood pressure monitoring. The results showed an improvement in blood pressure when OAT was used and compared to controls. An even stronger trend toward lowering blood pressure was observed when patients with normal blood pressure and those with mild OSA were excluded in the analysis.
Effect of oral appliances on blood pressure in obstructive sleep apnea: a systematic review and meta-analysis. 4
The objective of this study was to conduct a meta-analysis of studies that have evaluated the effect of oral appliance therapy on blood pressure. Data from observational and randomized control trials were extracted from seven studies involving 399 patients utilizing OAT to manage their OSA. Pre- and post-treatment diastolic, systolic, and mean arterial blood pressure was analyzed. The meta-analysis shows oral appliances have a favorable effect on the systolic, diastolic, and mean arterial blood pressure.
Health outcomes of CPAP versus oral appliance treatment for obstructive sleep apnea5
The health effects of 108 patients, after 1 month of optimal CPAP and mandibular advancement device (MAD) therapy in the treatment of OSA, were studied. These patients were diagnosed with moderate to severe OSA. The 24-hour blood pressure, subjective sleepiness driving simulator performance, and quality of life (FOSQ, SF-36) were compared between these two treatment modalities. The findings were as follows: CPAP reduced the AHI to a greater extent (CPAP AHI=4.5±6.6/hr, MAD AHI=11.1±12.1/hr), but (self) reported compliance was higher on MAD (MAD: 6.50±1.3 hrs/night versus CPAP: 5.20±2.0 hrs/night). Neither treatment improved blood pressure (note how this contrasts with the above studies by Andren and Phillips). By comparison, the research demonstrated that sleepiness, driving simulator performance, and quality of life (QOL) improved on both treatments by similar amounts, although MAD patients tested better than CPAP for improving four general QOL areas.
Several recently published articles directly investigated side effects related to OAT. The articles explored temporomandibular disorders and occlusal (bite) changes.
Forces created by mandibular advancement devices in OSAS patients: a pilot study during sleep6
This study’s research measured the forces created by the progressive mandibular advancement during sleep. Nine patients were enrolled in this study and used Herbst-style devices. A pressure transducer system was placed on both the right and left lateral arm to measure the amount of force exerted for each millimeter of advancement. The mean force in this sample was 1.18 N/mm and showed an almost linear evolution. The author concluded that “the force values recorded in this study may explain the occlusal and skeletal side effects associated with long-term use of oral appliances.”
Long-term oral appliance therapy in obstructive sleep apnea syndrome: a controlled study on temporomandibular side effects7
The temporomandibular complex involves the temporomandibular joint and its supporting structures and the muscles of mastication. In this study, 51 patients were randomized to OAT and 52 to CPAP therapy in order to determine the effect of long-term OAT on these structures. After 2 months, 1 year, and 2 years of therapy, these patients were evaluated for the occurrence of pain-related temporomandibular disorders (TMDs). According to the authors, “This study shows that in the initial period after initiating oral appliance or CPAP therapy, the occurrence of (particularly pain-related) TMDs increases, being substantially higher (24%) in the oral appliance group than in the CPAP group (6%). No relationship could be found between the mean mandibular protrusion and the frequency of wearing the appliance during follow-up with the occurrence of pain and function impairment of the temporomandibular complex.”
The study also found no associations between pain intensity and mandibular protrusion and only minor changes in the occurrence of pain-related TMDs after 2 years of treatment in both groups.
Only in the initial period of treatment was the occurrence of pain-related TMD higher in the OAT group (24%) when compared to CPAP (6%). At the 2-year appointment, there was little difference between the two groups.
The incidence and prevalence of temporomandibular disorders and posterior open bite in patients receiving mandibular advancement device therapy for obstructive sleep apnea8
In this study, through questionnaires and clinical examination, a record of 167 patients’ occlusion plus their temporomandibular health was evaluated prior to initiating oral appliance therapy in the treatment of OSA. A total of 159 patients returned for evaluation after 118 days of OAT. A total of 129 patients returned for evaluation after 208 days and 85 returned after 413 days. The results of these evaluations showed that the use of MADs may lead to the development of TMDs in a small number of patients. Nevertheless, these symptoms are most likely transient. In this particular study, posterior open bites (significant bite changes) were found to develop in 17.9% of patients; however, only 28.6% of these patients were aware of any bite changes.
Objective measurement of compliance during oral appliance therapy for sleep-disordered breathing9
In this prospective clinical trial, 51 consecutive patients, blinded to the purpose of the study, utilized oral devices with an “embedded microsensor thermometer chip.” At 3 months, the results showed an overall objective mean rate of use of 6.6 ± 1.3 hours per day with a regular OA users’ rate of 82%.
Interestingly, in the randomized crossover trial of CPAP versus OAT by Phillips et al,5 the authors strongly suggested that the observed result of patients with moderate to severe OSA having similar outcomes “was most likely explained by the greater efficacy of CPAP being offset by inferior compliance relative to MAD.”
Without a robust body of research 20 years ago, oral appliances were used only as a last resort when CPAP failed. Now, over the last 10 years, indications for OAT have increased dramatically, as evidenced by the 2005 recommendations.2 As more oral appliance research is published and the body of evidence grows in the areas of health outcomes, side effects, and compliance, advances in patient care will follow. SR
Sheri Katz, DDS, Diplomate, American Board of Dental Sleep Medicine, received her dental degree from Emory University. Katz is past-president of the American Academy of Dental Sleep Medicine and holds membership in the American Dental Association and the Georgia Dental Association. She practices in Decatur, Ga, and has limited her practice to the treatment of patients with sleep-disordered breathing.
1. Thorpy M, Chesson A, Derderian S, et al. Practice parameters for the treatment of snoring and obstructive sleep apnea with oral appliances. SLEEP. 1995;18(6):511-513.
2. Sleep Apnea with Oral Appliances: An Update for 2005.
An American Academy of Sleep Medicine Report.
3. Andren A, Hedberg P, Walker-Engstrom M, Wahlen P, Tegelberg A. Effects of treatment with oral appliance on 24-h blood pressure in patients with obstructive sleep apnea and hypertension: a randomized clinical trial. Sleep Breath. 2012 Jul 21. [Epub ahead of print].
4. Iftikhar I, Hays E, Iverson M; Magalang UJ, Maas A. Effect of oral appliances on blood pressure in obstructive sleep apnea: a systematic review and meta-analysis. J Clin Sleep Med. 2013;9(2):165-742.
5. Phillips CL, Grunstein RR,
Darendeliler MA, et al. Health outcomes of CPAP versus oral appliance treatment for obstructive sleep apnea: a randomised controlled trial. Am J Respir Crit Care Med. 2013;187(8):879-87. Epub 2013 Feb 14.
6. Cohen-Levy J, Petelle B, Pinguet J, Limerat E, Fleury B. Forces created by mandibular advancement devices in OSAS patients: a pilot study during sleep. Sleep Breath. 2012 Sep 11. [Epub ahead of print].
7. Doff MH, Veldhuis SK, Hoekema A, et al. Long-term oral appliance therapy in obstructive sleep apnea syndrome: a controlled study on temporomandibular side effects. Clin Oral Investig. 2012;16(3):689-97. doi: 10.1007/s00784-011-0555-6. Epub 2011 May 3.
8. Perez C, de Leeuw R, Okeson J, Carlson C, Bush H, Falace D. The incidence and prevalence of temporomandibular disorders and posterior open bite in patients receiving mandibular advancement device therapy for obstructive sleep apnea. Sleep Breath. 2013;17(1):323-32.
9. Vanderveken O, Dieltjens M, Wouters K, De Backer W, Van de Heyning PH, Braem MJ. Objective measurement of compliance during oral appliance therapy for sleep-disordered breathing. Thorax. 2013;68(1):91-6.
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