In vitro comparative evaluation of dentinal microcracks formation during root canal preparation by different nickel-titanium file systems

Abstract

Aim: The aim of this study was to evaluate and compare dentinal microcracks formation during root canal preparation by different commercially available nickel-titanium (NiTi) file systems. Materials and Methods: Eighty-four single-rooted mandibular premolars were selected. All specimens were decoronated and divided into seven groups of 12 each. Teeth were mounted in the acrylic block with simulated periodontal ligaments. Twelve teeth served as a control in which no treatment was performed. Experimental groups were instrumented with Hand NiTi, ProTaper universal, ProTaper Next, Silk, WaveOne, and self-adjusting files (SAF). Roots were then sectioned 3, 6, and 9 mm from the apex, and the cut surface was observed under a stereomicroscope and checked for the presence or absence of dentinal microcracks. Results: SAF group and Hand NiTi group showed no cracks formation along with control group. ProTaper rotary files showed more number of cracks than ProTaper Next, Silk and WaveOne used in the study. However, no statistically significant difference was found among ProTaper rotary, ProTaper Next, Silk, and WaveOne (P > 0.05). Conclusion: All rotary files created microcracks in the root dentin at all three levels, whereas the SAF and hand files presented with satisfactory results with no dentinal microcracks.