The efficiency of ozone therapy and low-level laser therapy in rat facial nerve injury

Purpose: Comparison of low-level laser therapy (LLLT) and ozone therapy (OT) methods for the treatment of facial nerve injury (FNI) in rats, evaluated by histomorphometric measurement analysis. Materials and methods: Thirty rats were randomly divided into control (C), LLLT, and OT groups. The left facial nerves (FNs) of all rats (n = 30) were used in this study. These were held in a surgical clamp for 30 s to create neuropathic damage. The non-injured right FNs of the rats in the control group formed the fourth, sham (S) group in this study (n = 10). Therefore the total number of evaluated samples was 40. The injured FNs of rats in the control group were left to heal spontaneously, whereas LLLT was applied for 21 consecutive days (output 100 mW/cm(2) and wavelength 850 nm) and OT (2 ml; 80 mu m/ml) once every 2 days for 21 days. Results: After histomorphological evaluation, the OT group revealed statistically significant outcomes following FNI compared with the OT and control groups in terms of branching of nerve fibers (p = 0.003), nerve fiber diameters (p = 0.0398), nerve fiber areas (p = 0.042), and axon numbers (p = 0.0327). Although the LLLT group revealed a better healing process than the control group, the outcome was not statistically significant in terms of branching of nerve fibers (p = 0.6804), nerve fiber diameters (p = 0.7424), nerve fiber areas (p = 0.7048), and axon numbers (p = 0.7588). Conclusions: OT resulted in statistically significant differences in outcome when compared with the LLLT and control groups, and provided a safe and effective treatment for FNI in rats. OT could therefore be considered as an alternative treatment of FNI. Clinical studies should now be performed to establish whether comparable results can be achieved in humans. (C) 2020 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.