An in vitro comparison of the retreatment efficacy of different root canal sealers and solvents

Purpose: The aim of this study was to compare the effectiveness of different root canal filling solvents in removing filling material with AH Plus or MTA-Fillapex from premolar teeth with artificially created lateral canals.
Methods: One hundred twenty extracted single-rooted premolar teeth with standardized artificial lateral canals were prepared and obturated using AH Plus or MTA-Fillapex with a warm vertical compaction technique. Retreatment was performed using ProTaper Universal Retreatment instruments with four different conditions: No solvent (control), chloroform, endosolv, and eucalyptol solvent. Residual filling material in the main canals was evaluated under a stereomicroscope using pixel-based image analysis, while residual filling material in the lateral canals was assessed radiographically. Main canal data were analyzed using two-way ANOVA and post-hoc tests, whereas lateral canal data were reported descriptively.
Results: The type of sealer did not significantly affect the amount of residual filling material in the main canal. In contrast, the solvent type had a significant effect. Endosolv resulted in significantly less residual filling material compared with chloroform, eucaliptol, and the control group. In the lateral canals, no method provided measurable and consistent removal, and therefore only descriptive analysis was performed.
Conclusion: Endosolv was the most effective solvent for removing root canal filling materials from the main canal. However, the anatomical complexity of lateral canals limits the effectiveness of all retreatment procedures.

Keywords: Endodontic retreatment, lateral canal, root canal filling removal, solvents.