Volumetric analysis of dentin removed and microcracks post root canal preparation using different rotary file systems: A nano-computed tomography approach

Aim: Preservation of dentin and prevention of microcracks are critical in maintaining tooth integrity after root canal instrumentation. This study aimed to compare the impact of three rotary file systems – NT-Rainbow S, ProFit S3, and ProTaper Gold – on remaining dentin thickness and microcrack formation. Methods: Thirty extracted single-rooted mandibular premolars with Vertucci Type I canal configuration with <20° curvature were selected and decoronated to a 16 mm standard length. Samples were split into three groups ( n = 10) at random according to the file system used: NT-Rainbow S, ProFit S3, and ProTaper Gold. Nano-computed tomography (Nano-CT) scans were performed pre and postinstrumentation to assess dentin thickness at three different levels, total volume of dentin removed was assessed, and microcrack incidence in the middle, apical, and coronal thirds of the root. Statistical tests were performed utilizing Tukey’s post hoc test and one-way analysis of variance ( P < 0.05). Results: ProFit S3 preserved the greatest dentin thickness and showed the least canal volume change, followed by NT-Rainbow S and ProTaper Gold ( P < 0.05). The mean volume of dentin removed was less in Profit S3 files in comparison to the other two groups ( P < 0.05). The ProFit S3 group also exhibited the lowest incidence of microcracks in all three root thirds. Conclusion: Among the systems evaluated, ProFit S3 demonstrated superior performance in preserving dentin and minimizing microcrack formation during root canal preparation, suggesting it may offer enhanced clinical outcomes.