Effect of ultrasonic activation on the reduction of bacteria and endotoxins in root canals: a randomized clinical trial

Aim This randomized clinical trial aimed to compare the effectiveness of ultrasonic activation with that of nonactivated irrigation on the removal of bacteria and endotoxin from root canals. Methodology Fifty patients with necrotic pulps and asymptomatic apical periodontitis were randomly allocated into two groups according to the final irrigation protocol after root canal preparation: Group UI – ultrasonic irrigation (n = 25) and Group NI – needle irrigation (n = 25). The root canals were medicated with calcium hydroxide for 14 days. Microbiological sampling was performed before (S1) and after the root canal preparation (S2), after the irrigation protocols (S3) and after the removal of the intracanal medication (S4). Total bacteria counts were determined by qPCR and the endotoxin levels by the limulus amebocyte lysate assay. Intragroup analyses were performed using the Wilcoxon test for related samples, whereas intergroup analyses were performed using the Mann–Whitney U‐test (P