Abstract
BACKGROUND: This study investigated the levels of bone morphogenetic protein 2 (BMP-2), osteocalcin, and 3D CT Hounsfield units following hyperbaric oxygen therapy (HBOT) in patients with cleft lip and palate (CLP) undergoing alveolar bone grafts to provide a pilot evaluation of the role of HBOT in osteogenesis. METHODS: This prospective, quasi-experimental, pre-post-intervention study evaluated seven patients with CLP receiving HBOT after single-stage reconstructions with alveolar bone grafts. The outcomes included the serum levels of BMP-2 and osteocalcin and the 3D CT Hounsfield units obtained before and after the surgery, and after the five HBOT sessions, to a total of 12 measurements. The data were analyzed with linear mixed-effects models using the intervention stage (pre-surgery, pre-HBOT, first to fifth HBOT sessions) as covariates and adjusting for several baseline factors. RESULTS: A significant difference was found in outcome measures across time (ANOVA p < 0.001 for BMP-2 and osteocalcin, p = 0.01 for Hounsfield units), with mean values appearing to steadily increase once HBOT began. Regression analyses indicated that the effect of HBOT was evident in serum osteocalcin after the 1st HBOT session (adjusted b = 1.32; 95% CI 0.39, 2.25) and in serum BMP-2 after the third session (adjusted b = 6.61; 95% CI 1.93, 11.28). After the fifth session, the HBOT effect was fairly pronounced on the two outcomes: the adjusted increase compared to the baseline was 28.06 ng/mL for BMP-2 and 6.27 ng/mL for osteocalcin. Our mixed-effect models also showed a post-HBOT increase in Hounsfield units. CONCLUSION: We found an increase of BMP-2, osteocalcin, and Hounsfield units following the HBOT intervention. These may suggest an effect of HBOT on osteogenesis.