As the general public and our specialty better recognize the interactions between craniofacial form and overall health, orthodontists might be expected to become proficient in a broader range of health issues. Sleep disordered breathing, which includes snoring and obstructive sleep apnea (OSA), is one such field. More than 120 different oral appliances are currently available, and the demands on dentistry from the public continue to significantly increase annually. Orthodontists, based on their knowledge and training with functional appliances and their skills to evaluate jaw position and tooth movement, are ideally suited to provide oral appliances as an effective form of therapy.
There is much literature about the efficacy of oral appliances. Many extensive reviews have been written, and specific guidelines for therapy with oral appliances have been developed. An oral appliance is commonly regarded as a simple, silent, bed-partner friendly, less invasive, reversible, tolerable, and efficacious choice for mild-to-moderate OSA and has been demonstrated to have a beneficial impact on a number of essential medical outcomes, including polysomnographic data, subjective and objective measurements of sleepiness, cardiovascular functions, neuropsychological behaviors, and quality of life indexes. Clinical evidence-based studies have demonstrated solutions to manage titration and reduce side effects to enhance long-term compliance for adult patients. Patients who require oral appliances for snoring or OSA are referred directly to the dentist by their attending sleep physician or family physician after an assessment of their sleep disorder that can include at-home or in-hospital monitoring. A differential diagnosis of snoring or the type and severity of sleep disordered breathing is then communicated to the orthodontist at the referral. After the patient is examined and the appliance best suited for the patient is constructed, fitted, and adjusted, the appliance is gradually titrated (advanced forward) over several weeks or months until the snoring is reduced to an acceptable level, the symptoms of daytime sleepiness are reduced, or the patient cannot tolerate any further advancement. Current practice parameters from the American Academy of Sleep Medicine for the use of oral appliances indicate that they are to be used in patients with snoring, mild-to-moderate OSA, or severe OSA only if continuous positive airway pressure (CPAP) has failed. There is consensus that an optimal treatment protocol specific for each oral appliance is of primary importance to achieve a successful outcome. After an adequate titration period, the patient is referred back to the physician for follow-up to verify the effectiveness of the appliance. Assessment is required for OSA patients to verify the efficacy, and it might be indicated if the symptoms of OSA worsen or recur. In contrast, the guidelines of the American Academy of Sleep Medicine for surgical modifications of the upper airway in adults recommend that maxillary mandibular advancement is indicated in patients with severe OSA who cannot tolerate CPAP or in whom oral appliances have been considered and found to be ineffective or undesirable. Uvulopalatopharyngoplasty as a sole procedure does not reliably normalize OSA when treating patients with moderate or severe OSA. Laser-assisted uvulopalatopharyngoplasty is not routinely recommended for patients with OSA. Conclusions about surgical interventions in this field are challenging, since many procedures are used, and limited data have been published for each technique.
Effectiveness of oral appliances
Several factors appear to contribute to the effectiveness of oral appliances: appliance design and titration, the severity of the sleep apnea, the amount of advancement, the vertical opening of the mandible, positional sleep apnea, and the body mass index. Oral appliances appear to work by enlarging the upper airway patency at multiple levels and by improving muscle airway tone and thus decreasing upper airway collapsibility.
Calculated figures on therapeutic effectiveness suggest that greater compliance with oral appliances results in a similar effectiveness as with CPAP, which improves the oxygenation better but is often worn less.
Comparative effectiveness research is a rapidly developing field designed to conduct and synthesize research to compare the benefits and harms of specific therapies to prevent, diagnose, treat, and monitor health conditions in a real-world setting. Comparing markedly different therapies such as surgery and oral appliances is challenging, since very different side effects and trajectories of responses are obviously involved. Randomized controlled trials are essential for definitive research comparisons of effectiveness, but design challenges make the investigations complex. Nonpharmacologic interventions such as surgery and oral appliances are difficult to design with effective placebo controls. In addition, numerous challenges are involved to accurately define patient populations with complex polysomnography and site-to-site variability in clinical protocols and equipment.
It appears that titratable oral appliances are significantly more effective than single jaw position appliances. In a large sample of OSA patients treated with oral appliances, a reduction in events to less than 10 was seen in 66% of the patients treated with an adjustable appliance in comparison with 45% with a single jaw position appliance. In addition, failure rates with thermoplastic appliances appear to be high compared with custom-made appliances.
Comparing oral appliances with pharyngoplasty
Only 2 reports have been published that directly compare oral appliances and uvulopalatopharyngoplasty therapies. Wilhelmsson et al evaluated 95 OSA patients in 2 treatment groups and found that, using a definition of success of an apnea hypopnea index less than 10, the oral appliance group was 78% successful, and 51% of the patients in the uvulopalatopharyngoplasty arm were successful after 12 months. Walker-Engstöm et al quantified an oral appliance success rate of 63% vs 33% for uvulopalatopharyngoplasty after 4 years. Oral appliances had few adverse side effects, and repairs and adjustments were moderate. In comparison, 8% and 10% of the uvulopalatopharyngoplasty subjects complained of nasopharyngeal regurgitation and difficulty with swallowing, respectively.
Direct comparisons of oral appliance use, CPAP therapy, and behavioral modifications (eg, improved sleep hygiene and weight loss) suggest that only CPAP and oral appliances are effective in significantly reducing apnea hypopnea index scores. In a mild group of subjects (apnea hypopnea index scores, 5-15), both the CPAP and the oral appliances showed significant improvements in apnea hypopnea index scores, sleepiness, and functional status. When compared with a placebo such as an oral tablet, oral appliances improved the apnea hypopnea index scores and the sleep hypoxemia. When oral appliances are compared with sham appliances with no advancement or no intervention, only the subjects with oral appliances had a significant decrease in apnea hypopnea index scores.
Comparing oral appliances with pharyngoplasty
Only 2 reports have been published that directly compare oral appliances and uvulopalatopharyngoplasty therapies. Wilhelmsson et al evaluated 95 OSA patients in 2 treatment groups and found that, using a definition of success of an apnea hypopnea index less than 10, the oral appliance group was 78% successful, and 51% of the patients in the uvulopalatopharyngoplasty arm were successful after 12 months. Walker-Engstöm et al quantified an oral appliance success rate of 63% vs 33% for uvulopalatopharyngoplasty after 4 years. Oral appliances had few adverse side effects, and repairs and adjustments were moderate. In comparison, 8% and 10% of the uvulopalatopharyngoplasty subjects complained of nasopharyngeal regurgitation and difficulty with swallowing, respectively.
Direct comparisons of oral appliance use, CPAP therapy, and behavioral modifications (eg, improved sleep hygiene and weight loss) suggest that only CPAP and oral appliances are effective in significantly reducing apnea hypopnea index scores. In a mild group of subjects (apnea hypopnea index scores, 5-15), both the CPAP and the oral appliances showed significant improvements in apnea hypopnea index scores, sleepiness, and functional status. When compared with a placebo such as an oral tablet, oral appliances improved the apnea hypopnea index scores and the sleep hypoxemia. When oral appliances are compared with sham appliances with no advancement or no intervention, only the subjects with oral appliances had a significant decrease in apnea hypopnea index scores.
Comparing oral appliances with CPAP
Many studies have been completed to compare oral appliances and CPAP; they have consistently reported that CPAP is effective in reducing apnea hypopnea index scores and improving oxygen saturation levels more than oral appliances, but that patients wear their oral appliances longer. Both treatments appear to improve subjective and objective sleepiness, cognitive tests, and quality of life. Patients wear their oral appliances longer each night, and most patients indicate a clear preference for this form of therapy. Imbedded compliance monitors suggest that oral appliances are worn between 6.6 and 6.8 hours per night compared with 4 hours per night for CPAP. Calculated figures on therapeutic effectiveness suggest that greater compliance with oral appliances results in a similar effectiveness as does CPAP, which improves the oxygenation better but is often worn less. In a recent study, it was documented that most OSA patients who had already been successfully treated with CPAP could effectively use an oral appliance as a treatment alternative, since it partially or completely reduced the sleep-disordered breathing even in those with severe OSA. Both CPAP and oral appliances have an effect on blood pressure. Based on 20-hour monitoring, significant reductions in diastolic blood pressure and mean arterial pressure have been quantified with oral appliances.
Side effects of long-term oral appliance wear have been extensively reviewed, and it appears that 2 types of side effects occur. Minor side effects can occur at any stage in therapy and are typically resolved in a short time, often with limited intervention. Typical examples are temporomandibular joint discomfort (especially if the mandible has been titrated too far forward or too rapidly), tooth discomfort, salivation, dry mouth, gingival irritation, and morning-after occlusal changes. More severe and continuous side effects include temporomandibular, myofacial, and tooth pain. Jaw muscle exercises can be useful to relieve masticatory muscle stiffness, accelerate the repositioning of the mandible, and increase the occlusal contact area and the bite force after oral appliances are used. Care to reduce excessive vertical opening with oral appliances has been emphasized by sleep endoscopy, which has documented an increase in collapsibility of the airway with increased vertical opening.
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