Comparative micro-computed tomography analysis of the removal efficiency of calcium hydroxide-based and calcium silicate-based intracanal medicaments

This study aimed to evaluate the removal efficiency of three different intracanal medicaments using either single-syringe irrigation (S-SI) or multiple ultrasonic-activated irrigation (M-UAI). Forty-two extracted human mandibular premolars were prepared to a size of 30/0.06 taper and randomly assigned to two irrigation groups: S-SI and M-UAI. Each group was subdivided based on the intracanal medicament used: Calcipex II (calcium hydroxide-based; CP), Calfee paste (calcium hydroxide-based; CF), or Bio-C Temp (calcium silicate-based; BT) (n = 7 each). After 1 week of storage under 100% humidity at 37°C, the samples underwent removal using either S-SI (1.5 mL sodium hypochlorite, 30 s) or M-UAI (1.5 mL, sequentially: 17% ethylenediaminetetraacetic acid, distilled water, 6% sodium hypochlorite, and distilled water, with 30-s activation for each). Residual intracanal medicament volume was assessed using micro-computed tomography. Statistical analysis was performed using the Kruskal-Wallis test and Mann-Whitney U test (α = 0.05). In S-SI, CF was removed more effectively than CP. In M-UAI, CF and CP showed similar rates, whereas BT had a significantly lower removal rate. Removal efficiency varied among medicaments. CF demonstrated superior removability under both S-SI and M-UAI protocols compared with CP and BT.