Introduction
Continuous Positive Airway Pressure (CPAP) is the treatment of choice in patients diagnosed with Obstructive Sleep Apnea (OSA). However, it is prone to intolerance, and compliance is typically less than optimal [1]. As an alternative, it was thought that mandibular advancement devices (MADs) would be an effective treatment in patients with mild to moderate OSA who have failed treatment with CPAP therapy. It was also assumed that MADs would not be as effective as CPAP, and that complications would not occur; but occlusal changes with MADs are more common than previously thought [2]. Despite these findings, MADs have become a common treatment for OSA, and their primary use is in patients with mild to moderate OSA. In fact, recent studies indicate that MADs are also effective in controlling OSA in patients with severe OSA [3]. In a study of adults intolerant to CPAP, the respiratory disturbance index (RDI) decreased by about 50% with a MAD in the patients’ mouth during sleep [4]. But, the role of MADs in the treatment of severe OSA is still not well defined.
One study [5] investigated a thermoelastic MAD, and reported an increase in velopharyngeal airway size, as well as a reduction in the RDI, in patients with moderate to severe OSA when the device was worn while asleep at night. In view of these types of findings, the practice parameters of the American Academy of Sleep Medicine recommend MADs for mild to moderate cases of OSA, or for patients with severe OSA who are unable to tolerate or refuse treatment with CPAP [6]. However, other reports suggest that only 50% of the patients will be compliant with MAD therapy after about 3 years of use [7]. Therefore, we tested the hypothesis that severe cases of OSA can be addressed using biomimetic oral appliance therapy (BOAT; DNA appliance® system), which might mitigate long-term use and side effects of MADs, as no previous using this technique have been reported in the literature.
Methods and Samples
After obtaining informed consent, we included 15 consecutive adults that had been diagnosed with severe OSA following an overnight sleep study, but were unable to comply with CPAP according to a medical physician. The rights of the subjects were protected by following the Declaration of Helsinki. Inclusion criteria were: subjects aged >21 yrs. diagnosed with severe OSA following an overnight sleep study that had been interpreted by a physician; documented failure/ intolerance to CPAP therapy; good oral appliance compliance; no history of hospitalization for craniofacial trauma or surgery; no congenital craniofacial anomalies, and dentate upper and lower arches. The exclusion criteria included: age <21 yrs.; lack of oral appliance compliance; active periodontal disease; tooth loss during treatment; poor oral hygiene, and systemic bisphosphonate therapy. The study protocol (#121310) was reviewed and approved by the institution’s review board.
Following a confirmed diagnosis of severe OSA by a medical physician, careful history-taking and craniofacial examination was undertaken for each subject by a dentist with advanced training in dental sleep medicine, and each subject was treated using BOAT. BOAT differs from the conventional MADs as it aims to remodel the upper airway through combined maxillo-mandibular correction with or without primary mandibular repositioning. Therefore, a bite registration was obtained in the upright-sitting position with the jaw posture corrected in the antero-posterior and vertical axes specific for each subject, using a sibilant phoneme registration protocol or ‘phonetic bite’ [8]. Upper and lower polyvinylsiloxane impressions were also obtained. The upper model was then mounted on an articulator and the lower model was mounted relative to the upper model, using the bite registration captured. Blinded to two investigators (SC and GDS), a biomimetic oral appliance without primary mandibular repositioning (Daytime-Nighttime Appliance: DNA appliance®; Figure 1) was prescribed for half of the study population (8 subjects).
