Chihuahuan Propolis as a Non-Antibiotic Intracanal Agent Against Enterococcus faecalis: An In Vitro Intratubular Study

Persistent endodontic infections are frequently associated with Enterococcus faecalis, a microorganism capable of penetrating dentinal tubules and surviving conventional disinfection procedures. This in vitro study evaluated the antimicrobial activity of Chihuahuan propolis against E. faecalis using planktonic and intratubular infection models. Propolis extract was tested at concentrations of 15, 35, and 70 mg/mL and compared with triple antibiotic paste (TAP) as a clinically relevant intracanal medicament. Antimicrobial efficacy was assessed by disk diffusion, minimum inhibitory concentration (MIC), colony-forming unit (CFU) reduction in infected dentinal tubules, and scanning electron microscopy (SEM). Chihuahuan propolis exhibited concentration-dependent antimicrobial activity, with a MIC of 17.5 mg/mL. In the intratubular model, propolis at 70 mg/mL achieved a CFU reduction comparable to TAP after seven days of application. SEM analysis confirmed a marked reduction of bacterial colonization within dentinal tubules. Within the limitations of this in vitro, monoespecies model, Chihuahuan propolis demonstrated antimicrobial efficacy against E. faecalis comparable to TAP, supporting its further investigation as a potential non-antibiotic intracanal medicament.