Effect of Passive Ultrasonic Irrigation on Bacteria That Persist After Root Canal Preparation in Teeth With Apical Periodontitis

Although chemomechanical procedures promote a drastic bacterial reduction, many root canals remain infected, which points to the need for complementary procedures to improve root canal disinfection. Thus, this clinical study aims to evaluate the effect of passive ultrasonic irrigation as a supplementary disinfection procedure after root canal preparation. Microbiological samples of the root canals of 30 single-rooted teeth with apical periodontitis will be taken at different stages of the endodontic treatment: before preparation (S1), after chemomechanical procedures (S2) and after passive ultrasonic irrigation (S3). The samples will be submitted to the quantitative polymerase chain reaction for bacterial quantification and to the reverse transcription quantitative polymerase chain reaction for bacterial activity analysis. Data will be analyzed using the Wilcoxon test for paired samples (p < 0.05).