Antibacterial and Antibiofilm Potential of <i>Cedrus atlantica</i> and <i>Tetraclinis articulata</i> Essential Oils Against <i>Enterococcus faecalis</i> and Three <i>Streptococcus sp</i> . Isolates for Endodontic Use: An <i>in Vitro</i> Study

Objective The objective of the study was to evaluate the antibacterial and antibiofilm efficacy of three essential oils (EOs), two derived from Tetraclinis articulata and one from Cedrus atlantica , against selected endodontic pathogens including Enterococcus faecalis , Streptococcus mitis , Streptococcus sanguinis , and Streptococcus gordonii . Methods The three EOs were extracted by means of hydrodistillation. The antibacterial activities expressed through Minimum Inhibitory Concentrations (MICs) and Minimum Bactericidal Concentration (MBCs), were evaluated in the microdilution assay. The biofilm inhibition and the biofilm disruption were tested for T. articulata 2 EO in crystal violet assay. Results The total yield of C. atlantica , T. articulata 1 and T. articulata 2 obtained was 0.1%, 0.2% and 0.45%, respectively. The MIC values of C. atlantica and T. articulata 1 EOs were above 20 mg/mL, while the MIC values of T. articulata 2 ranged from 4.78 ± 1.48 to 19.43 ± 5.48 mg/mL. Among the isolates, S. gordonii exhibited the highest sensitivity, while E. faecalis was the least sensitive. All tested concentrations (MIC/8–MIC) of T. articulata 2 EO successfully inhibited biofilm formation of the endodontopathogenic biofilms, with inhibition ranging from 34.91% to 78.90%. T. articulata 2 EO also proved disruptive potential on pre-formed biofilm of S. sanguinis and S. mitis at all tested concentrations. Conclusion T. articulata 2 proved promising antibacterial and antibiofilm potential which may be considered in dentistry.