The Effectiveness of Different Sequences of Irrigation on Root Canal Disinfection: A Microbiological Study

This study evaluates the effectiveness of different sequences of irrigation using sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) on root canal disinfection, measured through bacterial reduction.

A total of 48 mandibular molars were divided into two groups. Group A received irrigation with NaOCl followed by EDTA, while Group B received EDTA followed by NaOCl. Passive ultrasonic irrigation (PUI) was applied in both groups. Bacterial samples were collected at three stages: before chemomechanical preparation (S1), after preparation (S2), and after ultrasonic activation (S3). Quantitative PCR (qPCR) was used to assess bacterial load reduction. ANOVA was performed to determine statistical significance.

Group A demonstrated a significant reduction in bacterial load at all stages, with an ANOVA F-statistic of 9.40 (P = 0.00023). Group B showed a less pronounced reduction, with an F-statistic of 14.99 (P = 0.0000031). Bacterial reduction was more effective when NaOCl was used first followed by EDTA.

The sequence of irrigation influences the effectiveness of root canal disinfection. NaOCl followed by EDTA achieved greater bacterial reduction compared to the reverse sequence.