Dentinal loss and cleaning efficiency of retreatment files with irrigation activation: An in vitro study

Aim: This study aimed to compare dentinal loss during retreatment using ProTaper Universal retreatment file versus NeoEndo retreatment file systems via cone-beam computed tomography (CBCT). In addition, it evaluated the efficacy of conventional needle irrigation, passive ultrasonic-activated irrigation (PUI), and laser-activated irrigation (LAI) in removing bioceramic sealer, utilizing both CBCT and SEM analysis. Subjects and Methods: Sixty mandibular premolars were obturated with bioceramic sealer, retreated using ProTaper Universal and NeoEndo systems, followed by irrigation activation techniques (conventional, ultrasonic, and Er:YAG laser). Dentinal loss was assessed via CBCT, and bioceramic sealer removal was evaluated via scanning electron microscope (SEM). Results: ProTaper Universal group showed a greater dentinal volume reduction (25%; P < 0.001), while NeoEndo group showed a reduction (18.18%; P < 0.001). Among irrigation protocols, Er:YAG laser activation produced a significant sealer reduction (44.44%), followed by ultrasonic (31.25%) and conventional irrigation (22.22%) ( P < 0.001). Conclusion: ProTaper Universal showed a greater dentinal loss than NeoEndo, though not statistically significant. Er:YAG LAI achieved significant sealer removal, followed by passive ultrasonic, both outperforming conventional irrigation with statistically significant cleaning efficacy.