Evaluation of Antimicrobial Effects of Three Antimicrobial Agents Against Pathogenic Root Canal Microbe Enterococcus Faecalis: An in Vitro Study

Abstract

Triple antibiotic paste (TAP) consisting of a mixture of 3 antibiotics (3-Mix) containing metronidazole, ciprofloxacin and minocycline is widely used in endodontics for root canal disinfection, particularly in regenerative procedures and for performing LSTR (Lesion Sterilization and Tissue Repair).According to numerous research, Enterococcus faecalis causes significantly persistent root canal infections and frequently demonstrates antibiotic tolerance. The present study aimed to evaluate and compare the antimicrobial activity of amoxicillin, ciprofloxacin and metronidazole individually and in dual and triple combinations against a specific pathogenic root canal bacteria namely E. faecalis (ATCC 29212) using broth macro dilution method by determining MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration) value. Results showed that in terms of MIC value, amoxicillin has lowest value among the three antimicrobials against E. faecalis and there was no inhibitory effect with metronidazole. In present study it is found that the combination of 10 µg/ml amoxicillin and 5 µg/ml ciprofloxacin is the most effective for elimination of E. faecalis (99.98% killing capacity). The current study can be further improvised by performing an in-situ study or performing it on bacterial biofilm model.