Effectiveness of Ozone Therapy in Non-Surgical Periodontal Treatment: A Meta-Analysis of Topical Applications

Background: Additional therapies (e.g., laser, photodynamic therapy, and ozone) have been reported to improve mechanical instrumentation and immune response in non-surgical periodontal therapy (NSPT). With this systematic review we evaluated the effectiveness of ozone therapy in reducing inflammation and progression of periodontal disease. Methods: Three electronic databases (PubMed, Scopus, and Cochrane Library) were searched for randomized and clinical trials on ozone therapy (gas, liquid, gel/oil) combined with NSPT. The study design followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines and the risk of bias was assessed using the RoB-2 tool. Results: Eight of the twenty-two studies reviewed reported on gaseous ozone, nine on ozone water, and five on ozonated oil/gel as an adjunct to mechanical periodontal instrumentation, often with scaling and root planing (SRP). Ozone was found to be more effective than SRP alone in treating inflammation, as measured with the gingival index (VMD −0.32; 95% confidence interval (CI) (−0.41; −0.24); p < 0.00001) and compared to chlorhexidine (CHX) (ozone gel; VMD −0.10; 95% CI (−0.20; −0.01); p = 0.03). The study findings were inconsistent, however, with several reporting clinical and microbiological benefit while others observed no marked improvement with the addition of ozone therapy to NSPT. Conclusions: While ozone therapy may represent a useful adjunct to NSPT, further research with larger study groups is warranted to determine its effectiveness. © 2025 by the authors.