Aim: The Aim of this study was to clinically evaluate the effect of using Nitrofurantoin as an intracanal medicament versus Calcium Hydroxide on bacterial load reduction in patients with necrotic single-rooted permanent mandibular premolars with single canal.

Methods: Twenty- eight patients with necrotic single canalled mandibular premolars were included. Patients were randomly assigned into two equal groups of 14 patients each. Nitrofurantoin (25 mg/mL) was used as an intracanal medicament in the teeth assigned to the intervention group; while Calcium Hydroxide was used in those assigned to the control group. Standard endodontic treatment was performed in two visits. The intracanal bacterial levels were assessed pre-instrumentation, post-instrumentation and after placement of intracanal medicament for 1 week; through microbiological sampling, transport, dispersion, dilution, culture, and counting of CFU/ml.

Results: Both Nitrofurantoin and Calcium Hydroxide revealed a significant reduction in the bacterial load following instrumentation.

Conclusion: The present study showed that both intracanal medicaments succeeded in significantly reducing bacterial levels in primary infected root canals with no statistically significant difference between the two medicaments.