Hamadan University of Medical Sciences Avicenna Journal of Dental Research 2423-7582 17 3 2025 09 29 Evaluation of the Effects of Pure Extracts of Licorice, Sage, and Grape Seeds on Streptococcus mutans and Enamel Remineralization: An Experimental Study 130 136 10.34172/ajdr.1838 EN Fatemeh Ahmadi-Motamayel https://orcid.org/0000-0002-7138-7690 Erfan Akbari https://orcid.org/0000-0002-9082-5553 Amin Doosti-Irani https://orcid.org/0000-0003-0623-7503 Dara Dastan https://orcid.org/0000-0002-7208-208X Mohammadreza Arabestani https://orcid.org/0000-0001-9991-8193 Fereshteh Najar-Karimi https://orcid.org/0000-0003-1913-559X Journal Article 10.34172/ajdr.1838 2024 04 07 2024 12 29 Background: Many plants and natural products have strong antimicrobial activity in addition to their side effects. The present study evaluated the antibacterial effects of plant extracts of licorice, sage, and grape seeds on the proliferation of Streptococcus mutans and enamel remineralization. Methods: After preparing the plant extracts, first, the antibacterial effect of each extract on S. mutans growth and proliferation was evaluated. Then, 128 teeth with intact cusps were selected, prepared, and placed in a demineralizing solution for 10 weeks. Subsequently, their surface microhardness was determined. Finally, teeth were subjected to a pH cycling procedure for 14 days after they were randomly assigned to the plant extract groups, and their surface microhardness underwent re-evaluation. Statistical analyses were conducted using Stata 14 at a 95% confidence interval. Results: All the studied plant extracts exhibited antimicrobial effects on S. mutans and increased the surface microhardness of the teeth. Generally, the differences in microhardness in each group and between the study groups were significant (P<0.001). Conclusion: Overall, all the plant extracts had antibacterial effects on S. mutans and assisted in remineralizing dental caries by inhibiting this bacterial species.