Retreatability of Bioceramic Sealer Using One Curve Rotary File Assessed by Microcomputed Tomography

Abstract

This article aims to evaluate the residual filling materials after retreatment of bioceramic sealer used in the obturation technique of mandibular molars with different root curvatures using microcomputed tomography (micro-CT). A total of 106 canals of mandibular molar teeth with closed apex, no fracture, calcification, or previously root canals treated were selected. Each tooth was mounted in acrylic resin blocks, and canals were instrumented with 06 One Curve rotary file and filled with gutta-percha and EndoSequence bioceramic (group A) or AH Plus sealer (group B) then subdivided into three groups (each) based on the degree of root curvature; mild (≤15°), moderate (16-30°), or severe (≥31°). Retreatment was done with the same rotary file. Samples were scanned before and after retreatment, and the volume of the residual materials was calculated. Data were statistically analyzed. The micro-CT scans show remaining filling in all canal levels of the two groups after retreatment. The mean values of all canals in bioceramic as well as AH Plus samples were significantly higher at coronal level (p < 0.001). In addition, the mean differences of distolingual canal after retreatment were not significantly different between the three levels in bioceramic group (p = 0.051). In regard to the AH Plus group, the mean values of mesiolingual canal after retreatment were statistically significant higher at coronal level (p < 0.001). Micro-CT tool provides a clear 3D visualization. Remnants of Bioceramic and AH Plus sealers were detected in different canal curvatures. The use of One Curve rotary file did not improve the removal of the filling materials. It is difficult to achieved complete removal of bioceramic filling material from the root canal system using rotary file.