Comparative evaluation of dentinal microcrack formation in the apical region of permanent teeth after root canal preparation with ProTaper Next and TruNatomy rotary file system – An SEM study

Aim: This study aimed to compare apical microcrack formation after root canal preparation by ProTaper Next (PTN) and TruNatomy (TRN) rotary file system using scanning electron microscopic analysis. Methods: Seventy-eight single-rooted human premolars were randomly divided into two experimental groups ( n = 39) according to the systems used for the root canal preparation: PTN (Dentsply Maillefer, Ballaigues, Switzerland) and TRN file system (Dentsply Sirona, Maillefer, Ballaigues, Switzerland) files working at the apical foramen (AF). Apical area (1 mm from AF) was sectioned using the diamond-cutting disc. All the sections were viewed under scanning electron microscope (SEM) individually by two observers for the presence of microcracks after root canal preparation. Results: In roots prepared with TRN and PTN rotary files, dentinal microcracks were present. There was a statistically significant difference between TRN rotary file group and PTN rotary file group ( P < 0.05), with PTN rotary files producing the most dentinal microcracks. Conclusion: TRN rotary files showed significantly less microcracks at apical levels of the root canals than PTN rotary files.