An in vitro study comparing the intracanal effectiveness of calcium hydroxide- and linezolid-based medicaments against enterococcus faecalis

Introduction: This study evaluated the efficacy of calcium hydroxide (CH), Vitapex (VP), linezolid (LZ), a combination of LZ with CH (LC), and a control group (N, no medicament) against Enterococcus faecalis (EF). Methods: Human single-rooted premolars were instrumented up to ProTaper size F3 files. EF suspension was inoculated into each root specimen and incubated. The medicaments were syringed into each root by weight and incubated. After 72 hours, 6 samples per group (among the 5 groups) were retrieved. A hole was drilled on each root, and the dentinal shavings obtained were allowed to fall in brain-heart infusion (BHI) broth. Dilutions from the broth were plated and spread over BHI agar and blood agar. Colony-forming units (CFU) of EF were measured from BHI agar. The procedure was repeated after 8 days and 14 days. Results: In group CH, the mean CFU (log 10 values) after 72 hours, 8 days, and 14 days were 1.17 ± 1.16, 3.33 ± 1.97, and 4.17 ± 1.17, respectively (statistically significant). In group VP, the mean CFU were 0.83 ± 0.75, 4.00 ± 1.67, and 4.83 ± 1.72. In group LZ, the mean CFU at 72 hours and after 8 days was 0.17 ± 0.41, and no CFU were found on the fourteenth day. Similarly, in group LC, the mean CFU at 72 hours and after 8 days was 0.50 ± 0.84, which increased to 1.33 ± 1.51 on the fourteenth day (not significant). Conclusions: LZ was found to be most effective on EF, followed by LC, CH, and VP.