Background: In recent years, the use of mouthwashes containing green tea (GT) extract has been reported to prevent tooth decay. In laboratory studies, GT has been shown to be effective in controlling dental plaque and erosion. The aim of this review study was to evaluate the effectiveness of GT extract in controlling tooth decay and erosion in randomized clinical trials.
Methods: By searching related keywords in the Scopus, PubMed, and WOS (Web of Science) databases, as well as searching for related studies in the Google Scholar database randomized clinical trial ( RCT) studies published in English by the end of 2019 were extracted. Then, eligible studies were carefully reviewed and the required data were extracted.
Results: A total of 12 eligible studies were included in the study. The inclusion criteria of the study were human RCT studies, English language, and GT intervention. The exclusion criteria of the study were lack of negative (placebo) or positive control group, studies examining the effect of GT derivatives, oral diseases such as periodontal disease, people undergoing orthodontic treatment, use of antibiotics at least two weeks before the study, incomplete methodology, defects in the results, and lack of access to the full text of articles. The number of subjects was 246 in the GT group, 157 in the placebo group, and 132 in the positive control group (sodium fluoride, chlorhexidine, neem extract, and probiotic). Eleven studies used GT mouthwash and one study used toothpaste containing GT extract. In studies with placebo, GT showed a significantly better effect on dental plaque, oral pH, modulation of dental erosion, and reduction of the number salivary S. mutans and lactobacilli colonies. Additionally, GT had a similar and comparable effect to positive control groups in modulating the above-mentioned indices.
Conclusion: GT extract can show anti-cariogenic and anti-erosive effects. Larger randomized clinical trials are needed to support our findings.