In recent times, the use of natural products has gained momentum, either as a treatment or as adjuvants for other drugs in the treatment of different conditions. Propolis is a natural substance produced by bees which has proven useful for treating periodontal disease. This systematic review and meta-analysis gather evidence of the effectiveness of propolis in this kind of condition. The MEDLINE, CENTRAL, PubMed, EMBASE and Web of Science databases were searched for scientific articles to identify the findings published up to October 2020. The MeSH phrases used in the search were: "periodontal diseases AND propolis treatment"; "gingivitis AND propolis treatment"; "periodontitis AND propolis treatment"; "propolis treatment AND oral health"; "propolis AND oxidative stress AND periodontitis". The Boolean operator "AND" was used to combine the searches. Randomized trials where propolis was used in the treatment of different periodontal conditions were included. Non-randomized clinical studies were systematically reviewed and 224 studies were detected, eight of which met the criteria for inclusion in the meta-analysis. Only three of these were selected for quantitative synthesis. In conclusion, propolis is safe to use and can improve the results of periodontal disease treatment, reducing probing pocket depth compared with treatment with a placebo (difference in means, fixed effects -0.67 [95% CI: -0.84, -0.50]).
Keywords: gingivitis; oral health; oxidative stress; periodontal disease/periodontitis; propolis.