Abstract
BACKGROUNDS: The aim of this study was to evaluate the efficacy of supplementary techniques, including conventional needle irrigation (CNI), EDDY (ED), EndoActivator (EA), passive ultrasonic irrigation (PUI), and XP-Endo Finisher R (XP-FR), in removing residual filling materials from oval-shaped root canals during non-surgical endodontic retreatment. METHODS: Sixty human mandibular premolar teeth were initially prepared using an R25 instrument and filled with gutta-percha points and Bioserra sealer. The initial filling material removal was performed with PTUR D1 (30/0.09) and D2 (25/0.08) files, and the root canals were finally shaped with an R40 instrument. The samples were randomly divided into 5 groups (n = 12) according to the irrigation activation techniques. Residual filling materials in the apical, middle, and coronal thirds were examined using a scanning electron microscope. Statistical analyses were performed using Kruskal-Wallis tests, with a significance level set at p < 0.05. RESULTS: In the ED and XP-FR groups, residue scores decreased from apical to coronal (p < 0.05). ED, PUI, and XP-FR showed significantly lower residue scores in all root thirds compared to CNI (p < 0.05) and in the middle third compared to EA (p < 0.05). EA showed lower scores only in the coronal third compared to the CNI group (p < 0.05). CONCLUSION: ED, PUI, and XP-FR did not show statistically significant differences, all activation techniques demonstrated better efficacy than the EA and CNI.