Research progress on the therapeutic roles and mechanisms of hydrogen-rich water in periodontitis

Hydrogen-rich water (HRW) shows excellent antibacterial, anti-inflammatory, antioxidant, and wound-healing properties and plays a positive role in the treatment of various diseases, such as brain injury, kidney injury, and periodontitis. Current studies found that HRW can inhibit periodontopathogenic biofilm formation, inhibit oral connective tissue and bone tissue destruction, and show anti-inflammatory and antioxidant properties in periodontitis. Additionally, HRW can alleviate periodontal tissue damage by inhibiting oxidative stress and up-regulating the expression of antioxidant enzymes, such as glutathione peroxidase and superoxide dismutase. HRW exerts anti-inflammatory effects by regulating the nuclear factor erythroid 2-related factor 2 and mitogen-activated protein kinase pathways, which are closely associated with inflammation. Additionally, HRW inhibits the expression of inflammatory cytokines, such as interleukins, inhibits the growth and proliferation of bacterial plaque biofilms, and down-regulates glycosyltransferases and glucan-binding proteins to prevent bacterial adhesion and subsequent development of periodontitis. Furthermore, HRW has a positive effect on the expression of various cell growth factors, α-smooth muscle actin, and type Ⅰ collagen, which promotes wound healing. Current clinical studies have demonstrated the biological safety of HRW (to a certain extent) and reported no adverse reactions. However, most studies on HRW in oral diseases are preclinical in vivo and in vitro studies. Therefore, further clinical studies are required to validate the therapeutic significance and optimal therapeutic regimen of HRW in human periodontitis. This article aims to review the therapeutic role and the underlying mechanisms of HRW in periodontitis.