Determining cutting efficiency of nickel-titanium coronal flaring instruments used in lateral action

Aim To develop a method to evaluate the cutting behaviour of nickel‐titanium (NiTi) coronal flaring instruments. Methodology BioRaCe BR0 (BR), HyFlex CM 1 (HY), ProFile OS No. 2 (PF) and ProTaper Sx (PT) instruments were used in simulated coronal flaring using a lateral action against bovine dentine blocks, at 250 and 500 rpm. Cutting efficiency was assessed by three methods: first, areas of notches produced by instruments were directly measured under a stereomicroscope. Second, dentine specimens were then analysed by surface profilometry to determine the maximum cutting depth and finally by microcomputed tomography to assess the volume of removed dentine. Data were compared using parametric tests with the significance level set at 0.05. Results For all three methods, HY and PF were the most and the least cutting‐efficient instruments, respectively (P