Bibloc and Monobloc Oral appliances in the Treatment of Obstructive Sleep apnoea : a Multicenter, Randomized, Blinded, Parallel-Group Trial

Introduction: The clinical benefit of bibloc over monobloc appliances has not been established in randomized trials treating obstructive sleep apnoea (OSA). We hypothesized that the two types of appliances are equally effective in treating moderate to severe OSA. Materials and methods: We performed a blinded, multicenter, randomized, controlled, prospective, parallel-group trial including patients aged 18 years or older who had moderate-to-severe OSA. Patients were randomly assigned to receive either a bibloc or a monobloc appliance with the intention to protrude the mandible 75% of the individual maximal protrusion capacity. At baseline a one-night respiratory polygraphy was done without any respiratory support. The polygraphy was iterated with the appliance in place at a 6-week follow-up. The primary outcome was the absolute change in the apnoea-hypopnea-index (AHI) from baseline to the 6-week follow-up, analysed in the per-protocol population. All patients who received an appliance were included in the safety analysis. This trial is registered with ClinicalTrials.gov, number NCT02148510, and approved by Uppsala Regional Ethical Review Board, Sweden (#2014/021). Results: We recruited patients from three dental specialist clinics in Sweden; enrolment of 302 patients was done between March 2014 and April 2016; 146 randomized to bibloc and 156 to monobloc appliance. Twenty-three patients in the bibloc group and 17 in the monobloc group were withdrawn due to reasons like appliance could not be fitted, lack of compliance, adverse events or non-valid follow-up polygraphy i.e. a per-protocol group of 123 bibloc and 139 monobloc treated patients. The mean change of AHI from baseline to 6 weeks of treatment was -13.8 (95% CI -16.1 to -11.5; p < 0.001) in the bibloc group and -12.5 (95% CI -14.8 to -10.3; p < 0.001) in the monobloc group. The mean difference was not significant between the groups (-1.3 (95% CI -4.5 to 1.9). The most common adverse event in the orofacial region was upper airway infection followed by complains from various parts of the mouth, jaws and teeth. Conclusions: Bibloc and monobloc appliance treatment was equal in their effects in treating OSA as measured by at home polygraphic respiratory measures and the appliances were associated with a similar degree of adverse events. Acknowledgements: Funding from Uppsala-Örebro Regional Research Council and Vastmanland County Council, Sweden

Use of bibloc and monobloc oral appliances in obstructive sleep apnoea : a multicentre, randomized, blinded, parallel-group equivalence trial

Background: The clinical benefit of bibloc over monobloc appliances in treating obstructive sleep apnoea (OSA) has not been evaluated in randomized trials. We hypothesized that the two types of appliances are equally effective in treating OSA. Objective: To compare the efficacy of monobloc versus bibloc appliances in a short-term perspective. Patients and methods: In this multicentre, randomized, blinded, controlled, parallel-group equivalence trial, patients with OSA were randomly assigned to use either a bibloc or a monobloc appliance. One-night respiratory polygraphy without respiratory support was performed at baseline, and participants were re-examined with the appliance in place at short-term follow-up. The primary outcome was the change in the apnoea–hypopnea index (AHI). An independent person prepared a randomization list and sealed envelopes. Evaluating dentist and the biomedical analysts who evaluated the polygraphy were blinded to the choice of therapy. Results: Of 302 patients, 146 were randomly assigned to use the bibloc and 156 the monobloc device; 123 and 139 patients, respectively, were analysed as per protocol. The mean changes in AHI were −13.8 (95% confidence interval −16.1 to −11.5) in the bibloc group and −12.5 (−14.8 to −10.3) in the monobloc group. The difference of −1.3 (−4.5 to 1.9) was significant within the equivalence interval (P = 0.011; the greater of the two P values) and was confirmed by the intention-to-treat analysis (P = 0.001). The adverse events were of mild character and were experienced by similar percentages of patients in both groups (39 and 40 per cent for the bibloc and monobloc group, respectively). Limitations: The study shows short-term results with a median time from commencing treatment to the evaluation visit of 56 days and long-term data on efficacy and harm are needed to be fully conclusive. Conclusion: In a short-term perspective, both appliances were equivalent in terms of their positive effects for treating OSA and caused adverse events of similar magnitude. Trial registration: Registered with ClinicalTrials.gov (#NCT02148510)