Evaluation and Comparison of Microcracks in Radicular Dentine Following the Use of Different Root Canal Instruments – <i>In Vitro</i> Study

Objectives: To evaluate and compare microcracks in radicular dentine following the use of different root canal instruments in vitro study. Material and Methods: For this study, 120 freshly extracted teeth were selected. These teeth were extracted for orthodontic or periodontal reasons to evaluate and compare the microcracks in radicular dentine following the use of different root canal instruments. The teeth were then adjusted to 16mm from the apex to standardizethe specimens. Subsequently, the teeth were re-evaluated using a stereomicroscope for the detection of cracks and fractures. The teeth were then divided into fourgroups. To prepare the access cavity, the teeth were placed in acrylic blocks. Each tooth was wrapped in aluminum foil, which was peeled off later, and the periodontal ligament was simulated using hydrophilic vinyl polysiloxane impression material that replaced the space created by the foil, and the root was immediately repositioned until the material set. Results: In the HERO Shaper group (n=15, 100.00%), dentinal microcracks were detected in 13 (86.67%) samples and not detected in the remaining two(13.33%) samples.On the other hand,in the WaveOne Gold group (n = 15, 100.00%), none of the samples had dentinal microcracks. In the control group, 2% K files, none of the samples had dentinal microcracks (n =30, 100.00%). In the Hand ProTaperGroup (n = 15, 100.00%), the maximum number of teeth wasdetected with microcracks. Conclusion: The present study revealed that all rotary as well as hand systems, except for 2% stainless steel K hand files, caused microcracks at each level, significantly more at the apical level.