Iranian Dental Association Journal of Iranian Dental Association 3060-8201 36 3-4 2024 10 01 Efficacy of newly introduced intracanal medicament MTA mixed with Chlorhexidine against Enterococcus faecalis biofilm; an ex-vivo experiment 91 100 EN Sholeh Ghabraei https://orcid.org/0000-0003-3929-1506 Mahsa Sobhi Afshar https://orcid.org/0000-0002-5017-3853 Mohaddeseh Haghighi https://orcid.org/0009-0007-8995-4116 Fatemeh Malekpour https://orcid.org/0000-0002-1018-1154 Farzaneh Afkhami https://orcid.org/0000-0002-7678-5313 Journal Article 2025 12 17 2026 05 16 Objective(s): This study evaluated the antibacterial effectiveness of newly introduced intracanal medicament by comparing its antibacterial performance against Enterococcus (E.) faecalis biofilm at different dentinal depths with that of commonly used intracanal medicaments in an ex vivo model. Materials and Methods: Thirty-eight single-root human extracted teeth were infected with E. faecalis following chemo-mechanical preparation. After 14 days of incubation, the root canals were disinfected using five different medicaments (n=6): triple antibiotic paste (TAP), double antibiotic paste (DAP), 2% Chlorhexidine digluconate (CHX) gel, calcium hydroxide [Ca(OH)2] +CHX 2% and mineral trioxide aggregate (MTA) + CHX 2% and a control group. The medicaments were removed after 7 days, and dentin shavings were collected from root canals in three depths. The number of colony-forming units (CFU)/ml was counted for each sample. Results: All medicaments showed antibacterial properties against E. faecalis biofilm. Among the tested medicaments, TAP demonstrated the highest efficacy in eradicating bacterial biofilm across all three depths of the dentinal tubules, followed by DAP, with no statistically significant difference between them. In contrast, the MTA/CHX mixture exhibited the lowest antibacterial activity and did not differ significantly from the control group (p>0.05). Conclusion: Application of antibiotics as intracanal medicament can decrease the number of E. faecalis biofilms. The mixture of MTA and CHX has a low antibacterial effect in the root canal system.