Aim: The aim of the study was to evaluate the effects of curcumin mouthwash and curcumin–rosemary mouthwash against Streptococcus mutans (S. mutans) colonies in patients undergoing orthodontic treatment. Materials and methods: Around 48 subjects were randomly allocated to three groups, group I (chlorhexidine mouthwash), group II (curcumin mouthwash), and group III (curcumin–rosemary mouthwash). Plaque samples were collected at three stages, T1—before bonding, T2—1 month after bonding orthodontic attachments, and T3—after the use of the prescribed mouthwash for a period of 1 month. The collected samples were cultured and the number of S. mutans colonies were counted. The quality of the mouthwash was assessed using a questionnaire. Since the data were normally distributed, paired t-test and one-way analysis of variance (ANOVA) were used to evaluate the difference within and among the groups, respectively. Categorical data were analyzed using the Chi-square test. Results: The results obtained showed a significant reduction in the S. mutans colonies at T3 after the use of mouthwash for 1 month in all three groups. Patients in groups II and III had temporary discoloration of the tongue, whereas patients in group I had a burning sensation in the oral mucosa on prolonged use.

Conclusion: All three types of mouthwashes were effective in the reduction of S. mutans colonies in orthodontic patients. Clinical significance: The new herbal mouthwash are cost-effective and had negligible side effects when compared to chlorhexidine. Therefore, they can be used as mouthwashes for all patients regardless of socioeconomic background.