Antibacterial effect of green tea infusion used as a mouthwash on saliva and bacterial plaque: a randomized controlled trial.

The objective of this study was to evaluate the antibacterial effect of a green tea infusion used as a mouthwash. In this double-blind, randomized controlled study, simple randomization was used to divide 28 students, 18 to 40 years of age, into 2 groups (n = 14): green tea (intervention) or distilled water (placebo). A 13% green tea infusion was prepared with 13 g of green tea (commercially fractionated) in 100 mL of saline solution at a temperature of approximately 90 degrees C. The liquid was poured into sterile glass containers, as was the distilled water for the control group. The antibacterial effect was determined by counting the colony-forming units in cultures of plaque and saliva samples, which were obtained before and immediately after the students rinsed their mouth once with 10 mL of the green tea or control solution. The data were subjected to t tests to analyze differences before and after the intervention and between groups (green tea versus distilled water) (P < 0.05). The analysis showed statistically significant differences between the groups (P < 0.05), with participants in the green tea group demonstrating greater reductions in the numbers of colony-forming units. Green tea mouthwash had an antibacterial effect on saliva and bacterial plaque, suggesting that green tea mouthwash could be a beneficial addition to standard oral hygiene measures. Trial registration: ClinicalTrials.gov Identifier NCT04410666.