Obstructive sleep apnea treated with custom-made bibloc and monobloc oral appliances: a retrospective comparative study

PURPOSE: The primary purpose of this hypothesis-generating retrospective study was to compare the effect of monobloc and bibloc (Narval™) appliances on the apnea–hypopnea index (AHI) and the total cost of treatment during the first year of treatment. METHODS: Obstructive sleep apnea (OSA) subjects treated with a monobloc or bibloc during two different time periods were identified from medical records and data were extracted. Subjects treated with either of the appliances passed the same primary examination, follow-up visits, and follow-up polygraphic examination. A 1-year clinical follow-up was made on the bibloc group. RESULTS: The study analysis included 110 monobloc- and 55 bibloc-treated subjects with baseline mean AHI of 23 and 22, respectively. AHI responders (AHI < 10 and/or a ≥50 % reduction of baseline AHI) were seen at follow-up in 61 % of the monobloc group and 56 % of the bibloc group. The improvement of the AHI value was similar in the two groups, with mean declines of 12.7 and 13.8, respectively. The ODI (oxygen desaturation index), lowest SpO(2), longest apnea, and the mean Epworth sleepiness scale (ESS) score were significantly reduced by 3.1 (monobloc) and 2.2 (bibloc), i.e., at the same level for both groups. The total direct cost of treatment for a 1-year treatment was 17 % higher for the bibloc-treated subjects than for the monobloc-treated subjects. CONCLUSIONS: The results indicate that the monobloc and bibloc appliances are equally effective but the cost of treatment over 1 year was higher with the bibloc. However, prospective randomized controlled trials are needed to adequately test the assumption that the two treatment modalities are equally effective.