Ozonated water as a preventive oral hygiene aid: a systematic review and meta-analysis of its role in reducing dental plaque

Ozonated water is increasingly being explored as a gentler alternative to chlorhexidine for chemical plaque control because of its antimicrobial and anti-inflammatory properties and the absence of common side effects such as staining or altered taste. However, the evidence on its effectiveness—especially in healthy individuals—remains unclear. This systematic review and meta-analysis aimed to determine whether ozonated water is more effective than placebo or chlorhexidine mouthwash in reducing dental plaque. An extensive literature search was carried out across PubMed, Cochrane Library, Scopus, Web of Science, LILACS, ScienceDirect, EBSCOhost, and Google Scholar up to August 5, 2025. Randomized controlled trials involving healthy participants and comparing ozonated water with placebo or chlorhexidine were included. In total, five studies were selected for qualitative synthesis, of which four were included in the meta-analysis. Risk of bias was assessed using the RoB 2 tool, and the certainty of evidence was evaluated using the GRADE approach. A random-effects model was applied to calculate standardized mean differences (SMDs) with 95% confidence intervals. The meta-analysis suggested that ozonated water may provide slightly better short-term plaque reduction than placebo or chlorhexidine (SMD = −1.35; 95% CI: −2.77 to 0.06). However, as the confidence interval crossed the line of no effect, this difference was not statistically significant. Risk of bias was high in one study, unclear in three studies, and low in one study. The overall certainty for plaque reduction was rated as “low”. While ozonated water appears to be a promising short-term option for plaque control—especially for individuals unable to tolerate chlorhexidine—the current evidence is not strong enough to confirm that it works better than standard rinses or even plain water. Well-designed, longer-term clinical trials are needed before ozonated water can be recommended for routine daily use.