Antibacterial activity of garlic extract, tea tree oil, and its mouthwashes against Streptococcus mutans and Lactobacillus: An In vivo study

Abstract

Background: A wide group of microorganisms is identified from carious lesions, of which Streptococcus mutans and Lactobacillus acidophilus are the main pathogenic species involved in the initiation and propagation of dental caries. Mouthrinses can deliver therapeutic ingredients and benefits to all accessible surfaces in the mouth. With the increasing use of drugs, microorganisms are attaining resistance to commonly used antibiotics, which leads to the downfall of the effectiveness of conventional medicines, and therefore, a search for new antimicrobial agents has become necessary. The objective of the study was to evaluate the effect of mouthwashes containing garlic extract (GE), tea tree oil (TTO), and chlorhexidine (CHX) on salivary S. mutans and Lactobacillus. Methods: An in vivo parallel study was conducted among 90 18–25-year-old subjects. GE (2.5%) and TTO (0.2%) mouthwashes were prepared for use in the study. Commercially available CHX mouthwash (0.12%) was used as a positive control. The study duration was 5 weeks. The participants were randomly assigned into three groups with 30 participants in each group. To assess the residual effects following discontinuation of mouthwashes, saliva samples were collected on the 18th and 24th days. One-way ANOVA was used to assess the mean colony difference. Results: No significant difference in the counts of S. mutans and Lactobacillus was observed at baseline and 6th day between all the three groups. On the 12th day, the highest reduction in S. mutans and Lactobacillus counts was observed following the use of TTO mouthwash, followed by CHX mouthwash. The reduction in the count of S. mutans was significantly higher in the TTO group on the 24th day comparable to the garlic mouthwash group, followed by the CHX mouthwash group. Conclusion: Both GE and TTO mouthwashes demonstrated a significant antibacterial activity against S. mutans and Lactobacillus in vivo, with TTO demonstrating the greatest effect.