Evaluation of Microcracks formed During Root Canal Preparation by Different File Systems Using Micro-computed Tomography: An In Vitro Study

Abstract

The purpose of this study was to evaluate and compare the incidence of dentinal microcracks after instrumentation with various types of nickel-titanium (NiTi) files in rotary and reciprocating motion. Fifty human extracted mandibular molars were taken and divided into five groups (n = ten teeth per group). Group I included ProTaper Gold, group II included OneShape, group III included WaveOne Gold, group IV included Reciproc, and group V included hand K files. The teeth were desectioned at the cemento-enamel junction (CEJ) and dentinal microcracks were observed under Micro-computed tomography. Postoperative Micro-computed tomography analysis of the samples was conducted to inspect cracks in the images obtained before and after preparation. Results confirmed that there was a statistically significant difference between the study groups (p <0.05). The highest percentage of microcracks was seen in ProTaper Gold followed by OneShape. WaveOne Gold and Reciproc showed closely similar percentage of microcracks followed by hand K files that showed the least. Both rotary file systems showed higher number of microcracks than reciprocating file systems. Hand K files showed least microcracks formation among all studied groups. Among all the tested methods and systems, hand K files demonstrated least incidence of dentinal microcracks. However, these hand K files systems are not advanced and have certain practical limitations. Reciprocating systems usually exhibits clinically acceptable microcracks therefore they may be judiciously utilized. Rotary file systems showed excellent biomechanical outcomes with redundant microcrack formation. Hence, precise selection of a particular system must be solely dependent upon the clinical decision making and circumstantial requirements.