Comparative In Vitro Evaluation of the Effectiveness of AF Blue R3 and AF Blue S-One Rotary File Systems in S-Shaped Root Canal Preparation

Complex, S-shaped root canals present significant challenges in endodontic preparation, requiring effective canal shaping while maintaining original canal morphology. This study aims to evaluate and compare the performance of two single-file rotary systems, AF Blue R3 and AF Blue S-One, in maintaining canal shape and centralization in simulated S-shaped root canals. Forty resin-based simulated root canals with S-shaped curvature were randomized into two groups of 20 canals each. Each group underwent root canal preparation using either the AF Blue R3 (group A) or AF Blue S-One (group B) file system. Pre- and post-preparation scans were taken using cone-beam computed tomography (CBCT) to evaluate changes in canal volume, shape, and centering ability. Canal transportation was measured at specific points, including coronal, middle, and apical thirds, using image analysis software (Mimics Innovation Suite 21). The data were statistically analyzed using paired and independent samples t-tests and chi-square tests, with significance set at p ≤ 0.05. Both systems demonstrated effective canal shaping with minimal deviation. Canal volume was significantly larger after preparation with AF Blue R3 system compared to S One (R3= 17.11 m3, S-one= 14.56 m3, P=0.000). AF S-one had significantly higher canal transportation (100%) compared to R3 (94%) (P=0,004). Neither system resulted in file breakage. AF Blue R3 and AF Blue S-One rotary systems effectively prepared S-shaped root canals while preserving canal morphology. AF Blue R3 was more effective in maintaining apical anatomy, while AF Blue S-One demonstrated better centralization in the coronal and middle regions. Both systems are recommended for complex canal curvatures, although no single system achieved complete canal preparation.