Induction of dentinal microcracks during postspace preparation: A comparative microcomputed tomography study

INTRODUCTION: This study evaluated and compared techniques of postspace preparation for induction of dentinal microcracks utilizing microcomputed tomography (CT). MATERIALS AND METHODS: A total of 45 extracted micro-CT scanned mandibular premolars were prepared and obturated. After the second micro-CT, samples were divided into three groups (n = 15). In Group 1, postspace preparation was done using hand K files up to the size of #110. In Group 2, postspace preparation was done using Peeso reamer up to the number of #3. In Group 3, postspace preparation was done using ParaPost XT Drills with the tip diameter of 1.1 mm. Thereafter, the third micro-CT scan was performed for microcracks evaluation, and statistical analysis was performed. RESULTS: Few unprepared samples showed the presence of microcracks (1.54%). There was statistically significant (P < 0.05) percentage increase in the number of microcracks after root canal preparation and obturation (5.44%) and after postspace preparation (8.35%). The percentage increase in microcracks observed for Group 1, 2, and 3 from obturation to postspace preparation was 0.19%, 4.21%, and 6.86%. There was a significant difference among the three techniques of postspace preparation (P < 0.05). CONCLUSION: Microcracks may exist preoperatively. Postspace preparation increased the number of microcracks irrespective of the technique utilized. ParaPost XT Drills produces maximum microcracks in the root dentin followed by Peeso reamers and K files.