The Efficacy of Device Designs (Mono-block or Bi-block) in Oral Appliance Therapy for Obstructive Sleep Apnea Patients: A Systematic Review and Meta-Analysis

Oral appliance (OA(m)) therapy has demonstrated efficacy in treating obstructive sleep apnea (OSA). The aim of this systematic review was to clarify the efficacy of device designs (Mono-block or Bi-block) in OA(m) therapy for OSA patients. We performed a meta-analysis using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system. Two studies (Mono-block OA(m) versus Bi-block OA(m)) remained eligible after applying the exclusion criteria. When comparing Mono-block OA(m) and Bi-block OA(m), Mono-block OA(m) significantly reduced the apnea–hypopnea index (2.92; 95% confidence interval (95%CI), 1.26 to 4.58; p = 0.0006), and patient preference for Mono-block OA(m) was significantly higher (2.06; 95%CI, 1.44 to 2.06; p < 0.0001). Lowest SpO(2), arousal index, non-REM stage 3, sleep efficiency, Epworth Sleepiness Scale (ESS), Snoring Scale, and side effects were not significantly different between the two groups (lowest SpO(2): −11.18; 95%CI, −26.90 to 4.54; p = 0.16, arousal index: 4.40; 95%CI, −6.00 to 14.80; p = 0.41, non-REM stage 3: −2.00; 95%CI, −6.00 to 14.80; p = 0.41, sleep efficiency: −1.42, 95%CI, −4.71 to 1.86; p = 0.40, ESS: 0.12; 95%CI, −1.55 to 1.79; p = 0.89, Snoring Scale: 0.55; 95%CI, −0.73 to 1.83, p = 0.55, side effects: 1.00, 95%CI, 0.62 to 1.61, p = 1.00). In this systematic review, the use of Mono-block OA(m) was more effective than Bi-block OA(m) for OSA patients.