Modified biblock versus monoblock mandibular advancement appliances for treatment of obstructive sleep apnea: A randomized controlled trial

Abstract

Statement of problemThe high prevalence of obstructive sleep apnea represents a serious public health problem. Oral appliances have gained wide acceptance among patients diagnosed with obstructive sleep apnea, who should wear them every night. A comfortable oral appliance is mandatory for successful treatment outcomes. PurposeThe purpose of this randomized controlled trial was the assessment of the influence of 2 different designs of the mandibular advancement appliance (MAA), modified biblock and monoblock, for the management of obstructive sleep apnea. Material and methodsThe study was designed as a prospective 2-arm randomized controlled clinical trial conducted in parallel. Twenty participants (aged 40 ±7.5 years) diagnosed with moderate obstructive sleep apnea were randomly assigned to a control group (n=10), receiving monoblock MAA, and a study group (n=10), receiving modified biblock MAA with elastics. Both appliances were fabricated by using computer-aided design and computer-aided manufacture (CAD-CAM) technology at different mandibular advancement levels (MALs): 50% and 75% of maximum MAL. A total of 60 cone beam computed tomography scans, 60 overnight full polysomnography sleep tests, 60 STOP-Bang questionnaires, and 40 Usability of Sleep Apnea Equipment-Oral Appliance (USE-OA) questionnaires were collected and analyzed blindly at baseline (initial visit), 50% MAL (3 months), and 75% MAL (6 months). The main outcome measures were the upper airway volume, linear anteroposterior and cross-sectional airway measurements, Apnea Hypopnea Index, Respiratory Disturbance Index, STOP-Bang questionnaire scoring, and USE-OA questionnaire scoring. Nonparametric statistical analysis was performed by using a statistical software program (α=.05). With a beta error accepted of up to 20%, the power of the study was 80%. ResultsAt 75% MAL, the percentage change in upper airway volumetric measurements showed a favorable increase: biblock group (115%) and monoblock group (42%), with a statistically significant difference (P=.001). The linear anteroposterior airway measurements and the percentage change in cross-sectional airway measurements were statistically similar: biblock group (80%) and (75%) monoblock group (60%), (54%) (P=.450, P=.151, respectively). The percentage change in the Apnea Hypopnea Index significantly decreased: biblock group (-89%) and monoblock group (-54%) (P<.001). The percentage change in the Respiratory Disturbance Index decreased: biblock group (-78%) and monoblock group (-62%) (P<.023). From the STOP-Bang questionnaire scoring, 100% of both groups showed low risk for obstructive sleep apnea at 75% MAL. From the satisfaction scoring on the USE-OA questionnaire, the biblock group was 100% strong satisfaction and the monoblock group was 50% satisfaction and 50% fairly satisfied. ConclusionsThe modified biblock MAA with elastics showed significant improvements in patients diagnosed with obstructive sleep apnea regarding upper airway measurements and full polysomnography vital parameters when compared with monoblock MAA.