Abstract Background Retreatment in curved root canals, particularly achieving complete canal cleanliness, remains a clinical challenge and an ongoing subject of investigation. This study evaluated the efficiency of sonically activated irrigation (EDDY) and diode laser–activated irrigation (DL) in removing filling material from simulated curved canals. Methods Thirty-three J-shaped resin blocks were instrumented to 25/06 apical size and obturated with single-cone resin sealer and gutta-percha. Retreatment was performed using ProTaper Universal Retreatment files. Samples were allocated to needle irrigation (NI, control), EDDY, or diode laser (DL) groups. NI and EDDY protocols were applied for 3 × 20 s, while the DL protocol consisted of four 5-second activation cycles. Sections at apical (2 mm), middle (6 mm), and coronal (10 mm) levels were examined at ×40 magnification. ImageJ, image analysis software was used to calculate the percentage of remaining obturation material. Two-way repeated measures ANOVA was used ( p ≤ 0.05). Results EDDY achieved significantly superior cleaning at the apical 2 mm and middle 6 mm levels compared with both NI and DL ( p 0.05). In both NI and DL groups, filling material removal effectiveness differed significantly among the apical, middle, and coronal thirds ( p 0.05). Conclusion Although none of the methods achieved the complete removal of filling materials, EDDY was significantly more effective than needle irrigation and diode laser activation in the apical and middle region of curved canals. These findings suggest that, to significantly improve apical cleanliness, clinicians should consider sonic activation during retreatment in curved canals.
Ürün et al. (Mon,) studied this question.