Evaluation of the root canal sealing properties and removability of four bioceramic sealers using micro–computed tomographic

Bioceramic sealers have been increasingly applied in endodontics due to their excellent sealing properties and biocompatibility. However, the sealing performance of different bioceramic sealers and their removability during re-treatment remain focal points of clinical concern. This study aimed to evaluate the root canal sealing performance and removability of four bioceramic sealers. One hundred extracted human single-rooted premolars were randomly allocated into five experimental groups (n = 20) after standardized root canal preparation: SC1 (i-MTA SP), SC2 (C-root SP), SC3 (Neosealer Flo), SC4 (iRoot SP) using single-cone obturation, and warm vertical compaction (WVC) with AH-plus. Micro CT scans were performed at three distinct intervals (immediately, one-week, and one-month post-obturation) to quantify the percentage volume of voids (PVV). After one-year storage, sealer removal was performed using ProTaper Universal Retreatment system combined with ultrasonic agitation. Residual filling rate (RFR) was calculated via post-retreatment micro CT scan and reconstruction. Data were analyzed using the Kruskal-Wallis H-test and the Friedman test, with the significance level set at 5% (p < 0.05). The PVV at the same site exhibited no statistically significant differences between the groups at three distinct intervals. Immediately following the filling procedure, the PVV in the middle thirds of roots in the SC4 group was significantly less than that in the SC1 and WVC groups (p < 0.05). The PVV in the middle thirds was less than in the coronal thirds in the SC2 group, and the PVV in both the apical and middle thirds was less than in the coronal thirds in both the SC3 and SC4 groups (p < 0.05). One-week post-filling, the PVV in the middle thirds of roots in the SC2 group was less than that in the WVC group. The PVV in the middle thirds of roots in the SC3 group, apical and middle thirds of roots in both the SC2 and SC4 groups was less than coronal thirds (p < 0.05). One-month post-filling, the PVV in the apical thirds of roots in the SC1 group, middle thirds of roots in the SC3 group and apical and middle thirds of roots in both the SC2 and SC4 groups was less than coronal thirds of roots (p < 0.05). Post-retreatment analysis demonstrated significantly less RFR in SC1 apical thirds compared to SC4 (p < 0.05). The choice among the bioceramic sealers tested had no significant effect on the sealing quality of single‑cone obturation. Among the four bioceramic sealers evaluated, i MTA SP was more readily removed than iRoot SP.