Purpose: The purpose of this study was to determine whether treatment outcomes vary according to the design of the mandibular repositioning appliance (MRA). Two titratable MRA's were compared. The designs differ in advancement hardware and configuration of acrylic both in bulk and interocclusal contact.
Materials and methods: The primary treatment outcome was the Respiratory Disturbance Index (RDI). Other outcomes that were compared included Sleep Apnea Quality of Life Index (SAQLI), Epworth Sleepiness Scale, oxygen saturation, and subjective feedback regarding experiences with the appliances. Twenty-four subjects were recruited from consecutive referrals for MRA therapy following diagnosis of obstructive sleep apnea (OSA) by polysomnography. Subjects were randomly assigned to a treatment arm of the crossover study. Each subject underwent an initial sleep study with a type III home monitor to establish a baseline RDI. Subjects were then treated with one of the two MRAs determined by random assignment. The MRA self-titration phase was monitored until a treatment position was determined, and the home sleep study was repeated. After a 2-week period without any OSA treatment, subjects received the second MRA and the self-titration treatment protocol was repeated. At completion of treatment with each appliance, subjects answered questionnaires and underwent a sleep study with the type III monitor. The outcome data for each appliance were compared using analysis of variance.
Results: Eighteen subjects completed the treatment protocol. There were no significant statistical differences in treatment outcomes between the two appliances. There was a statistically significant (p ≤ 0.05) preference for a MRA design with minimal coverage of teeth and palate. The subjects' appliance selection was consistent with a corresponding reduction in SAQLI score for the selected appliance.
Conclusion: Although no statistically significant difference was observed between the two appliances in the outcomes measured, there was a trend toward greater improvement with the appliance with less acrylic resin bulk and less interocclusal contact. MRA selection should favor titratable, unobtrusive designs with appropriate construction to promote acceptance and adherence to MRA therapy.