Efficacy of glycolic acid at different concentrations for smear layer removal with various activation systems.

BACKGROUND: This study aimed to evaluate the effects of different irrigation solutions and activation systems on smear layer removal. METHODS: Ninety mandibular canines were instrumented using T-Endo Must files (#40.04) and randomly assigned to nine groups (n = 10) according to the final irrigation protocol: Group 1a (17% EDTA, Needle), Group 1b (5% GA, Needle), Group 1c (10% GA, Needle), Group 2a (17% EDTA, EDDY), Group 2b (5% GA, EDDY), Group 2c (10% GA, EDDY), Group 3a (17% EDTA, XP-F), Group 3b (5% GA, XP-F), and Group 3c (10% GA, XP-F). Smear layer removal was evaluated using scanning electron microscopy. A three-way analysis of variance with Bonferroni correction was performed to assess the effects of the independent variables and their interactions, and Tukey's post hoc test was used for pairwise comparisons. Statistical significance was set at p < 0.05. RESULTS: Root section, irrigation solution, and activation system each significantly affected smear scores (p < 0.0001). A significant two-way interaction was observed between root section and irrigation solution (p = 0.025). Smear scores increased from the coronal to the apical third of the root canal. Both 5% and 10% GA significantly reduced smear scores compared with 17% EDTA (p < 0.05), and activation using EDDY and XP-F resulted in significantly lower smear scores compared with needle irrigation (p < 0.05). CONCLUSION: Both 5% and 10% GA resulted in lower smear scores, while irrigation activation with EDDY and XP-F significantly enhanced smear layer removal.