Background: Complete root canal filling material removal throughout the retreatment is essential for effective disinfection and long-term treatment success. Bioceramic-based sealers, while offering excellent sealing and biocompatibility, are difficult to remove due to their chemical bonding and deep dentinal tubule penetration. Chelating agents such as 17% EDTA can dissolve the inorganic smear layer, and ultrasonic activation has been proposed to enhance its cleaning performance. Aim: To evaluate the effectiveness of ultrasonic activation of 17% EDTA in removing bioceramic sealer remnants compared to EDTA without activation and file-only retreatment.Materials and Methods: A total of 30 extracted human mandibular premolars have been prepared, obturated with a bioceramic sealer, and incubated for four weeks. The specimens have been allocated randomly to three groups (n = 10 each): Group1 – 17% EDTA with no ultrasonic activation; Group2 – 17% EDTA with ultra-sonic activation; Group3 – control (files only). Retreatment has been performed with the use of ProTaper Universal Retreatment files. In Groups 1 and 2, EDTA has been delivered with a 30-gauge side-vented needle; in Group2, ultrasonic activation was applied for 20 seconds initially and 30 seconds during final irrigation. Samples were sectioned, imaged under SEM at coronal, middle, and apical thirds, and analyzed using ImageJ to quantify the percentage of uncleaned surface area. Data had been evaluated with the use of Shapiro–Wilk and one-way ANOVA tests (p < 0.050). Results: Mean residual debris was 39.8% ± 2.5 (EDTA + ultrasonic), 47.3% ± 2.8 (EDTA alone), and 65.2% ± 3.1 (control), showing significant differences (p < 0.001).Conclusion: Ultrasonic activation markedly enhanced sealer removal, especially in the apical third, improving overall canal cleanliness.
Saleh et al. (Mon,) studied this question.