Aim: The aim was to assess the incidence of dentinal cracks following root canal instrumentation by means of ProTaper Next, ProTaper Gold and E-flex Gold rotary files.

Methodology: Samples were based on one hundred extracted lower first molars. They were allocated into a control group of ten teeth and three experimental groups of thirty specimens. Mesiobuccal canals were instrumented using ProTaper next, Protaper Gold and E-Flex Gold. Transverse sectioning was done at 3mm, 6mm, and 9mm from the apical end and stereomicroscopically viewed. Chi- Square test followed by Fischer exact tests were used for statistical analysis of the data set.

Results: The control group had no cracks. E flex Gold files yielded significantly less cracks than ProTaper Gold and ProTaper Next, (p ˂ 0.05). The middle and apical thirds showed more cracks than the coronal third.

Conclusion: Eflex Gold resulted in less dentinal crack formation than Protaper Gold and Protaper Next.