Hydrogen-Rich Water for the Treatment of Experimental Peri-Implantitis

Background: Due to its antioxidant and anti-inflammatory effects, hydrogen-rich water has been used to reduce inflammatory responses in many inflammatory diseases. However, its efficacy in treating peri-implantitis remains unclear. This study aims to investigate the efficacy of hydrogen-rich water in reducing inflammatory responses in experimental peri-implantitis.Methods: A ligature-induced experimental peri-implantitis model was established using three Beagle dogs (n = 24 implants). The implants were divided into two groups: a hydrogen-rich water-treated group (n = 12 implants), and a non-treated control group (n = 12 implants). The clinical indices, including the gingival index (GI), modified sulcus bleeding index (mSBI), and probing depth (PD), were examined. Hematoxylin and eosin (H&E) staining was used to assess the inflammatory cell infiltrate in the peri-implant tissue. Additionally, three host-derived pro-inflammatory cytokines, interleukin-1 (IL-1), interleukin-6 (IL-6), and matrix metalloproteinase-8 (MMP-8) were assessed using enzyme-linked immunosorbent assay (ELISA). Furthermore, microbial community profiles were analyzed using high-throughput sequencing (HTS) technology.Results: In terms of the GI, the differences between the control and treated groups at 0, 2, and 4 weeks were not statistically significant (all p > 0.05). However, the GI value in the treated group at 6 weeks was significantly lower than that in the control group (p = 0.005). As for the PD, the differences between the control and treated groups at 0, 2, 4, and 6 weeks were not statistically significant (all p > 0.05). Regarding the mSBI, the difference between the control and treated groups at 0 week was not statistically significant (all p > 0.05), while the mSBI value in the treated group at 2, 4, and 6 weeks was significantly lower than that in the control group (p = 0.008, p = 0.005, p = 0.001). Compared to the non-treated group, the hydrogen-rich water-treated group showed a significantly lower number of inflammatory cells, lower pro-inflammatory cytokines, IL-1, IL-6, and MMP-8 levels (p < 0.05). Additionally, there was a significantly decreased relative abundance of pathogenic bacterial species including Porphyromonas gingivalis, Fusobacterium nucleatum, Fusibacter, and Fretibacterium (p < 0.05).Conclusions: The use of hydrogen-rich water for treating peri-implantitis showed promise and effectiveness within the scope of this study.