BMC Oral Health, cilt.26, sa.1, 2026 (SCI-Expanded, Scopus)
Background: The irregular morphology of internal root resorption (IRR) cavities complicates non-surgical retreatment by limiting effective cleaning and complete removal of filling materials. This study aimed to assess the effectiveness of three supplemental techniques—the EndoActivator System (EAS), passive ultrasonic irrigation (PUI), and XP-Endo Finisher R (XPR)—for removing filling materials from simulated IRR cavities. Methods: One hundred single-rooted maxillary central incisors were decoronated and split longitudinally. Standardized simulated IRR cavities (0.8 mm depth, 1.6 mm diameter) were prepared using a round diamond bur, followed by a nitric-acid demineralization protocol. Hemisections were reassembled with cyanoacrylate gel and sealed with wax. The canals were obturated with gutta-percha and AH Plus using lateral condensation apically and continuous heat vertical compaction in the IRR region. Five teeth served as negative controls and five as positive controls. After mechanical filling removal, the remaining specimens were randomly assigned to three supplementary cleaning techniques—PUI, EAS, and XPR (n = 30). All groups received the same NaOCl–saline–EDTA irrigation regimen. Residual filling material was assessed by two independent examiners under ×12.5 magnification and quantified using ImageJ software. The data were compared between groups using Kruskal–Wallis tests, and intra- and inter-examiner agreement was assessed using the intraclass correlation coefficient (ICC). Results: None of the supplemental techniques achieved complete removal of filling material from the simulated IRR cavities. Numerical differences among PUI, EAS, and XPR were small and not statistically significant (p > 0.05). Inter- and intra-examiner agreement was excellent (ICC > 0.95). Conclusions: All three techniques reduced residual filling material in the simulated IRR cavities, but none achieved complete cleaning, and no statistically significant differences were found among groups.