Ozone therapy as a complementary approach in periodontal therapeutics

Liu J, Huang Y, Huang J, Yang W, Tao R. Effects of ozone therapy as an adjuvant in the treatment of periodontitis: a systematic review and meta-analysis. BMC Oral Health 2025; 25: 335.

The authors conducted a systematic search across: 1. PubMed (MEDLINE); 2. Embase; 3. Cochrane Central Register of Controlled Trials (CENTRAL). Key question Does adjunctive ozone therapy improve periodontal clinical parameters (probing depth, gingival inflammation, bleeding, plaque levels, and attachment loss) in patients with chronic periodontitis compared to conventional scaling and root planing (SRP) alone? The study follows the PICO framework: 1.

Patients with chronic periodontitis; 2.

SRP + ozone therapy (ozonated water or gaseous ozone); 3. Comparison: SRP + placebo (e.g., saline, distilled water) or no adjunct; 4.

Probing depth (PD), gingival index (GI), bleeding on probing (BOP), plaque index (PI), and clinical attachment level (CAL).

Combined Medical Subject Headings (MeSH) terms and free-text keywords related to ozone ("Ozone," "Ozonated water," "Gaseous ozone") and periodontitis ("Chronic periodontitis," "Periodontal therapy").

Inclusion criteria: Study Design: 1. Only randomized controlled trials (RCTs); 2.

Adults with chronic periodontitis (no systemic diseases or pregnancy). 3.

SRP + ozone therapy (either ozonated water irrigation or gaseous ozone insufflation). 4.

SRP + placebo (e.g., saline, distilled water) or no adjunct. 5.

At least one of the following-PD, GI, BOP, PI, or CAL.

1. Animal/in vitro studies; 2. Studies involving antibiotics, lasers, or other adjuncts; 3. Incomplete data or non-RCT designs. Screening process: 1. Initial Search: 99 records identified; 2. After Duplicate Removal: 62 studies screened; 3. Full-Text Review: 22 articles assessed, 13 met inclusion criteria. Final included studies: 1. 8 used ozonated water (concentration range: 2-85 μg/mL); 2. 5 used gaseous ozone (varying exposure times); 3. Follow-up periods: 4 weeks to 3 months.

Data collection: 1. Two independent reviewers extracted data to minimize bias; 2. Extracted variables: study design, sample size, ozone concentration, application method, follow-up duration, and clinical outcomes.

1. Primary effect measure: weighted mean difference (WMD) with 95% confidence intervals (CI). 2. Heterogeneity assessed via I² statistic: (a) For Low (0-50%): Fixed-effects model was used. (b) For High (>50%): Random-effects model was applied. 3. Sensitivity Analysis: Excluded studies one by one to assess robustness. 4. Publication Bias: Evaluated via funnel plots and Egger's test.

1. Probing Depth (PD) reduction: (a) 12 studies, 655 patients. (b) Significant improvement (WMD = -0.26 mm, P = 0.01). (c) Heterogeneity: High (I² = 78%). (d) Interpretation: Ozone + SRP reduces pocket depth more than SRP alone, but variability in ozone application methods may influence results. 2. Gingival Index (GI) improvement: (a) 7 studies. (b) Significant reduction (WMD = -0.15, P = 0.0006). (c) Heterogeneity: Moderate (I² = 48%). (d) Interpretation: Ozone reduces gingival inflammation, likely due to its anti-inflammatory and antimicrobial effects. 3. Bleeding on Probing (BOP): (a) 6 studies. (b) No significant difference (P = 0.23). (c) Possible Reason: Bleeding is influenced by systemic factors (e.g., smoking, diabetes) not fully controlled in studies. 4. Plaque Index (PI) & Clinical Attachment Level (CAL): (a) No significant improvements (P > 0.05). (b) CAL Heterogeneity: High (I² = 72%). (c) Interpretation: Ozone may not enhance plaque control or tissue regeneration beyond SRP alone.

1. Ozone therapy along with SRP is superior to SRP alone in reducing PD and GI, suggesting benefits in pocket depth and inflammation control. 2. No significant effects on BOP, PI, or CAL, indicating ozone may not improve all periodontal parameters. 3. Safe & well-tolerated: no adverse events reported.