In vitro evaluation of dentin removal, canal transportation, and centering ratio of three rotary file systems in curved root canals: A cone-beam computed tomography study

Abstract Introduction: Preserving the original canal anatomy while achieving efficient shaping is a major challenge in curved root canals. This study aimed to compare the shaping performance of three rotary file systems: Neoendo Neotaper, ProTaper Next, and HERO Shaper Gold, using cone-beam computed tomography (CBCT). Materials and Methods: Forty-five extracted mandibular first molars with 25°–30° curved mesiobuccal canals were randomly divided into three groups ( n = 15). Each group was instrumented with one of the rotary systems following the manufacturers’ protocols. Pre- and postinstrumentation CBCT scans were obtained at 3 mm and 7 mm from the apex to evaluate dentin removal, canal transportation, and centering ratio. Statistical analysis was performed using one-way analysis of variance and Tukey’s post hoc test ( P < 0.05). Results: Neoendo Neotaper exhibited the least dentin removal and canal transportation at both levels, while ProTaper Next demonstrated the best centering ability. HERO Shaper Gold showed the highest dentin removal and transportation, particularly at the 7-mm level. The intergroup differences were statistically significant ( P < 0.05). Conclusion: Neoendo Neotaper preserved canal anatomy most effectively, ProTaper Next achieved optimal centering, and HERO Shaper Gold produced the greatest dentin loss. CBCT proved to be a reliable tool for three-dimensional evaluation of canal shaping.