Assessment of Nitrofurantoin as an Experimental Intracanal Medicament in Endodontics

Background and Objectives. Multiple antibacterial agents have been mixed and used as an intracanal medicament-like modified triple antibiotic paste (MTAP) to eliminate Enterococcus faecalis (EF), which has been most frequently identified in the cases of failed root canal treatment and periapical lesions. This study is aimed at using a single antibacterial agent, nitrofurantoin (Nit), as an experimental intracanal medicament paste against different clinical isolates of EF bacteria and at comparing its antimicrobial efficacy with MTAP. Materials and Methods. Three strains of EF (S1, S2, and S3) were clinically isolated. A total of 198 straight single-rooted human teeth were collected and divided randomly into three main groups: group N (Nit) (n=90), group M (MTAP) (n=90), and group W (distilled water) (n=18). The main groups were subdivided into three subgroups according to the strain of EF: in groups N and M, subgroups S1, S2, and S3 (n=30), while in group W, subgroups S1, S2, and S3 (n=6). Then, each subgroup of N and M was divided into five groups (n=6) according to the concentrations of Nit or MTAP (6.25, 12.5, 25, 50, and 100 mg/mL). The colony-forming unit (CFU) of EF from the canal lumen and dentinal chips was measured. Results. Nit could eradicate S1, S2, and S3 completely with concentrations of 6.25, 12.5, and 25 mg/mL, respectively, while MTAP showed complete eradication of the three strains only at 25 mg/mL. In all the groups, it was found that the CFU counts of EF in the dentinal chips were higher than those in the root canal lumen. Conclusion. At the concentration of 25 mg/mL, the Nit paste is effective in eradicating EF completely when it is used as an intracanal medicament