Effectiveness of brewed green tea and mouthwash containing green tea extract against Streptococcus mutans and Porphyromonas gingivalis in Saliva

Abstract

Background: Green tea is known to exert an antibacterial effect against cariogenic pathogens. Objectives: This study aimed to determine the effect of brewed green tea as mouth rinse against Streptococcus mutans and Porphyromonas gingivalis in saliva and compare it to the effect of a commercial mouthwash containing green tea extract. Methods: Saliva of 30 healthy individuals aged 19–40 years was collected before treatment, 1 min after gargling, and 1 week after daily treatment with brewed green tea as a mouth rinse or commercial mouthwash containing green tea. Bacterial DNA was extracted from salivary samples and evaluated using quantitative polymerase chain reaction. The total number of DNA targets was analyzed using SYBR Green and 16S ribosomal RNA gene-specific primers for S. mutans and P. gingivalis. The data were statistically analyzed using a paired t-test. The level of significance was set to P < 0.05. Results: Green tea mouth rinse and mouthwash containing green tea extract significantly reduced the number of S. mutans and P. gingivalis in the participants' saliva after 1 week of use (P < 0.05). There was no significant difference between the effects of brewed green tea mouth rinse and commercial mouthwash containing green tea. Conclusion: The use of mouthwash containing green tea and brewed green tea mouth rinse reduces the number of S. mutans and P. gingivalis in saliva. Brewed green tea can be used as a mouth rinse with effects comparable to those of commercial mouthwash containing green tea. Further studies are warranted to explore its effects on other oral pathogens.