Evaluation of the dislodgement resistance of bioceramic reparative cements placed in a retrograde cavity using a different technique

Aim: Calcium silicate-based fillings have been widely used in surgical endodontic treatment because of hard-tissue conductive and inductive properties. The aim of present study is to investigate the bond strength of different calcium silicate-based fillings in retrograde cavities. Methods: Forty-four maxillary single rooted teeth were endodontically treated. The apical portions of the teeth were removed and root-end cavities were prepared using an ultrasonic tip. The roots were randomly divided into four experimental groups (n = 11) according to the material used; (1) MTA-FILLAPEX, (2) MTA Repair HP, (3) MTA-FILLAPEX+ MTA Repair HP, and (4) MTA Plus. Two horizontal cross sections (1±0.1 mm thick) from each specimen were resected from the apices. These sections were placed in a universal testing machine to evaluate the push-out bond strength force required for dislodgement of the root end filling was recorded. The failure type was also evaluated by using a stereomicroscope. The differences in bond strength were analyzed using the two-way analysis of variance (ANOVA). Results: MTA-FILLAPEX and MTA Plus displayed the lowest and highest dislocation resistance, respectively (P < 0.05). In the apical level, bond strength was significantly higher than the coronal level in all groups except for MTA-FILLAPEX. Mixed failure was prevalent in all groups, except for MTA-FILLAPEX, which showed purely cohesive failures. Conclusions: Investigated calcium silicate-based filling materials showed different bond strength to the root-end cavity. The bond strength was significantly decreased when the prior application of MTA-FILLAPEX before delivery of MTA Repair HP