Electrolyzed saline as an alternative to chlorhexidine: Antimicrobial and biofilm volume outcomes in a 4-day non-brushing randomized controlled clinical trial.

BACKGROUND: The biofilm-inhibitory effects of electrolyzed saline (EOS) vary widely due to differences in formulations and treatment methods. This study analyzed the impact of EOS on key oral microbial species and used serial 3D-intraoral scans to evaluate its effects on de novo biofilm formation.

METHODS: This was a double-blind, randomized, placebo-controlled, cross-over, 4-day, non-brushing, plaque-regrowth study on periodontally healthy individuals. Each subject participated in three trial arms. During each 4-day arm, the subjects refrained from mechanical oral hygiene. Instead, they rinsed their oral cavities twice-daily with EOS, 0.12% chlorhexidine (CHX), or placebo. De novo plaque accumulation after 4 days was assessed as the primary outcome using the Turesky Modification of the Quigley-Hein Plaque Index (TMQHPI) and the volumetric plaque index (VPI). qPCR analyses of key-microbial species and measurements of active-matrix-metalloproteinase-8 (aMMP-8) in gingival crevicular fluid were performed to complement the clinical data.

RESULTS: The biofilm-inhibitory effect of CHX was superior to that of EOS at the level of TMQHPlI and VPI, although both significantly reduced biofilms compared with placebo. The broad-spectrum antimicrobial effect of CHX caused significant reductions in overall bacterial loads, while the action of EOS was more selective. Both CHX and EOS markedly reduced the bacterial loads of Tannerella forsythia; CHX remained more effective against Treponema denticola. In contrast, only EOS demonstrated stronger antimicrobial effects against Fusobacterium nucleatum and Prevotella intermedia while showing no significant impact on periodontal commensals. No significant effects on aMMP-8 were observed.

CONCLUSIONS: EOS showed substantial, but inferior biofilm-inhibitory, effects compared with CHX. However, EOS had more selective and dysbiosis-controlling effects than CHX. The clinical trial was registered at Clintrials.gov under no. NCT05709015.

PLAIN LANGUAGE SUMMARY: This study investigated the effectiveness of electrolyzed saline (EOS) in preventing biofilm build-up on teeth. The efficacy of EOS mouthwash was compared with a positive control (chlorhexidine, CHX) and a negative control (distilled water). A method based on 3D scans of teeth was used to measure changes in the biofilm volume. In the study, participants stopped brushing their teeth for 4 days and rinsed their mouths twice daily with either EOS, CHX, or a placebo instead. They were then assessed for biofilm levels and changes in oral bacteria numbers. The results showed that CHX was more effective than EOS in reducing biofilm, although both were more effective than placebo. Chlorhexidine significantly lowered harmful bacteria but also negatively affected the beneficial bacteria. On the other hand, EOS also reduced specific harmful bacteria, but did not lower the beneficial ones as much. Overall, while EOS was less effective at reducing biofilm than CHX, it was better at maintaining a healthy balance of oral bacteria.