RESUMO
OBJECTIVES: This study aims to formulate a new Origanum vulgare anti-caries dental gel with high antimicrobial activity. METHODS: O. vulgare essential oil was extracted using hydro-distillation, ethanol extraction, gas chromatography/mass spectrometry, and high-performance liquid chromatography methods. Antimicrobial activity of the produced gels with oregano oil and extract was determined through the disco-diffusion method. The effectiveness of O. vulgare essential oil was tested in vitro for Streptococcus mutans biofilm using colorimetric analysis. RESULTS: O. vulgare essential oil inhibited the growth of S. mutans biofilm by 98% compared with unexposed control bacteria (p <0.05). Five samples of anti-caries gel (ACDG1, ACDG2, ACDG3, ACDG4, ACDG5) were formulated using the obtained oregano essential oil and extract. Based on the microbiological study results, the ACDG1 and ACDG3 gel samples exhibited high antimicrobial activity against the gram-positive bacterial strains of Staphylococcus aureus and Bacillus subtilis and the yeast fungus Candida albicans and moderate antimicrobial activity against the gram-negative strains of Escherichia coli and Pseudomonas aeruginosa. CONCLUSION: Based on the results of this study, the ACDG3 sample may be considered an anti-caries gel owing to its high antimicrobial activity. This sample has good organoleptic properties compared to other samples, produces relatively high antimicrobial activity, and guards against cariogenic biofilms of S. mutans.