A comparative evaluation of the antimicrobial efficacy of triple antibiotic paste, clindamycin, and linezolid as an intracanal medicament against Enterococcus faecalis: An in vitro study

ABSTRACT Aim: The aim of the present study was to evaluate and compare the antimicrobial efficacy of three medicaments, triple antibiotic paste (TAP), clindamycin (CLID), and linezolid (LZ) against Enterococcus faecalis , using spectrophotometry. Methods: Seventy-two single-rooted human premolars were collected and prepared using standard protocol and were decoronated to obtain standardized lengths. A pure culture of E. faecalis (ATCC 29212) was procured, grown on blood agar, obtained using a wired loop, and suspended in brain heart infusion (BHI) broth for 24 h. After contaminating the canals with E. faecalis , the prepared samples were divided into three groups, with 24 teeth each, based on the intracanal medicament used, Group A: TAP (ciplox×500 mg, metrogyl 400 mg, minoz 100 mg) + normal saline (NS), Group B: CLID (capsule clid 150) + NS, Group C: LZ (Lizoforce, dry syrup) + NS. The medicaments were syringed into the roots and which were then incubated. After 24 h, 12 samples per group were thoroughly rinsed for removal of intracanal medicaments (ICMs), and instrumented using #4 GG drill to obtain dentinal shavings, which were allowed to fall into sterile BHI broth. The turbidity of the broth was assessed and the optical density (OD) was recorded using spectrophotometer to estimate the concentration of E. faecalis after 1 day. After a period of 7 days, the remaining 12 samples per group underwent identical processing. Results: At the end of day 1, all three antibiotics presented comparable values of OD indicating comparable antimicrobial efficacy. Group-wise comparison revealed that TAP continued to be superior to the other two antibiotics even at the end of 7 days. However, the difference was significant only between TAP and LZ with no significant difference between TAP and CLID and between CLID and LZ. Conclusion: The present study concludes that the use of single-antibiotic CLID and LZ may serve as an effective alternative to the multidrug combination TAP, as an ICM.