Evaluation of root canals filled with bioceramic sealer after retreatment with two different techniques

Purpose To evaluate the remaining filling material (gutta‑percha/EndoSequence bioceramic sealer) on root canal walls after retreatment using ProTaper universal retreatment (PTUR) system with and without chloroform solvent. Materials and methods Thirty extracted human premolars with type I root canal system were used. After crown removal and working length determination, all root canals were prepared using nickel–titanium rotary ProTaper system and obturated using gutta‑percha as a core filling material with EndoSequence bioceramic sealer. All roots were randomly divided into two equal main groups (n = 15) according to retreatment technique. Group I: filling materials was removed using PTUR system and chloroform as a solvent; while group II: filling materials was removed using PTUR system without solvent. Both groups were cleaved longitudinally and examined under scanning electron microscope to evaluate root canal filling remnants. Results PTUR system with the aid of chloroform recorded highest values of score percentage of remaining filling material at all tested root canal levels. The values of score percentage of remaining filling materials were significantly lower at coronal level compared to other tested levels. Conclusion Using chloroform during removal of root canal filling material using rotary instruments was associated with larger amount of residual root canal filling material compared to using rotary instruments only.