Comparative Evaluation of Penetration Depth and Antimicrobial Efficacy of Calcium Hydroxide, MAS Paste, Nitrofurantoin, and Levonadifloxacin against Enterococcus faecalis: A Confocal Laser Scanning Microscopic Study

Abstract

Aim: The most prevalent species in persistent and secondary infections linked to endodontic failure is Enterococcus faecalis. The objective of this in vitro investigation was to assess the antibacterial efficacy and penetration depth of calcium hydroxide, nitrofurantoin, levonadifloxacin, and a mixture of antibiotic and steroid paste (MAS paste) against E. faecalis. Materials and Methods: A total of 40 single-rooted tooth samples were decoronated apically and coronally to yield 10 mm root sections. All tooth samples were biomechanically prepared and were inoculated with E. faecalis bacteria for 21 days. The study involved four groups, each containing 10 teeth as follows: group 1—calcium hydroxide, group 2—MAS paste consisting of ciprofloxacin, metronidazole as antibiotics, and dexamethasone as corticosteroid, group 3—nitrofurantoin, and group 4—levonadifloxacin. For 7 days, the corresponding intracanal medications were injected into the canals. On the seventh day, dentinal debris was extracted from the blocked lumen to quantitatively evaluate the antibacterial activity of the experimental medications. The depth of penetration (DOP) of medicaments under study was assessed by viewing 1 mm thick horizontal sections under a confocal laser scanning microscope, one from each of the four subgroups. The sections were stained with florescent stain before being under the microscope. Results: Results showed that on day 7, the mean colony-forming units were lowest for levonadifloxacin, indicating the highest antimicrobial efficacy (P < 0.05). This was followed by nitrofurantoin, MAS paste, and calcium hydroxide. Additionally, levonadifloxacin achieved the greatest DOP, followed by nitrofurantoin, MAS paste, and calcium hydroxide. These results suggest a correlation between DOP and antimicrobial efficacy. Conclusion: Within the confines of this study, it can be concluded that levonadifloxacin exhibited the highest antimicrobial efficacy, even at a low concentration of 8 µg/mL. Therefore, it can serve as a viable intracanal medicament in endodontic therapy.