Plaque Inhibitory Effect of Neutral Electrolysed Water in the Form of a Mouthwash in a 4-day Non-brushing Model

Evaluation of a Mouthwash Formulation Containing Neutral Electrolysed Water on De-novo Plaque Formation, Gingival Inflammation, MMP-8 Activity and the Oral Microbiome

Electrolysed water (EOW) is produced by the electrolysis of sodium chloride in an aqueous solution, producing chlorine gas at the anode and sodium hydroxide and hydrogen at the cathode. EOW is known to have antimicrobial effects against various microorganisms, including viruses, bacteria, spores and fungi. Its antimicrobial activity is generally attributed to its hypochloric acid content - a product of chlorine gas dissolved in water. Due to its biocompatibility, known uses of EOW include ocular disinfection, nasal irrigation and chronic cutaneous wound care. In the dental setting, it may be used as a mouthwash, disinfectant, irrigant, mouthwash or dental gel.

The aim of this study is to investigate the effect of a mouthwash containing neutral electrolyzed water on plaque accumulation (evaluated using a disclosing agent and an intraoral scanner), gingival inflammation, MMP-8 activity and the oral microbiome. In this double-blind, cross-over, 4-day experimental gingivitis model, each subject will participate in all three arms of the study. Each arm will last 4 days, during which the subjects will be asked to refrain from toothbrushing and the use of interdental cleaning devices. Instead, they will be instructed to rinse their oral cavities twice daily with either EOW, placebo or a positive control (chlorhexidine), according to a randomisation chart (each subject will receive a different mouthwash type in every arm of the study). The outcomes will be assessed at baseline and after 4 days. A washout period of at least 7 days will be implemented between each study arm.

Inclusion criteria:

• age 20 - 30 years,
• non-smoker,
• systemically healthy,
• without regular systemic medication,
• presence of at least 6 teeth in each jaw quadrant,
• plaque index < 10 % at baseline visit,
• absence of periodontal pockets measuring > 4 mm.

Exclusion criteria:

• known allergy or suspected hypersensitivity to chlorhexidine digluconate,
• gingivitis,
• regularly use of mouthwash as part of oral hygiene routine,
• antibiotic treatment in the last 6 months or during the observation period,
• pregnancy or lactation,
• fixed or removable prosthetic devices, dental implants.