Effect of Solvent Use on Dentinal Integrity and Filling Removal During Endodontic Retreatment: A Micro-Computed...

This study evaluated, using micro-computed tomography (micro-CT), whether solvent use during endodontic retreatment influences dentinal defect formation and the removal of filling material compared with mechanical retreatment alone.

Twenty extracted human mandibular molars were prepared and obturated using standardized protocols and randomly allocated to solvent-assisted retreatment or retreatment without solvent (n=10 per group). Micro-CT scans were obtained before treatment, after obturation, and after retreatment at a voxel size of 13.68 μm. Dentinal defects were assessed using axial images, and residual filling-material volume was measured three-dimensionally in the apical, middle, and coronal thirds. Between-group comparisons were performed using the Welch independent-samples t-test or Mann-Whitney U test, as appropriate. Within-group comparisons were performed using the Friedman test.

No dentinal defects were detected in any specimen (0/20). However, the exact 95% confidence interval indicated that a low-incidence effect could not be excluded. Residual filling material was detected in all canals after retreatment. No significant differences were observed between the solvent-assisted and non-solvent groups in residual filling-material volume at any canal third after adjustment for multiple comparisons (all adjusted P>0.05).

Under the conditions of this in vitro study, solvent use did not significantly improve filling-material removal compared with mechanical retreatment alone. No dentinal defects were detected in either group; however, the exploratory nature and limited sample size of the dentinal-defect analysis preclude excluding a low-incidence effect.