Hamadan University of Medical Sciences Avicenna Journal of Dental Research 2423-7582 15 4 2023 12 29 Evaluation of Dentin Cracks by Stereomicroscope after Preparation of Mesiobuccal Canal of Maxillary First Molars Using Edge Taper Platinum and ProTaper Gold Rotary Files: A Laboratory Study 167 172 10.34172/ajdr.1637 EN Narjes Hoshyari https://orcid.org/0000-0002-2628-9290 Seyedali Seyedmajidi https://orcid.org/0000-0002-3841-0609 Anahita Lotfizadeh https://orcid.org/0000-0002-6466-6026 Eghlima Malakan https://orcid.org/0000-0002-8891-2359 Abolfazl Hosseinnataj https://orcid.org/0000-0003-0549-1788 Azam Haddadi Kohsar https://orcid.org/0000-0002-3360-7322 Journal Article 10.34172/ajdr.1637 2022 07 31 2023 09 27 Background: Successful root canal treatment depends on correct cleaning, widening, and shaping of the root canal system. Root canal preparation using rotary files can cause dentin cracks. This study aimed to evaluate the number of dentin cracks created after the preparation of the mesiobuccal root canal of the first maxillary molars by ProTaper Gold and Edge taper platinum rotary files using a stereomicroscope. Methods: In this laboratory study, 72 maxillary first molars were collected and randomly divided into three groups (n=24): control group, ProTaper Gold group, and Edge taper platinum group. Mesiobuccal canal preparation was performed in Edge taper platinum and ProTaper Gold groups up to file size F2. All roots were cut horizontally at distances of 3, 6, and 9 mm from the apex with a disc. The sections were examined under a stereomicroscope at 40x magnification. Fisher’s exact test and Chi-square test were used in SPSS version 22.0 for analyzing data. A significant level of 5% was considered. Results: In the control group, no cracks were observed in any of the sections. At 3 and 9 mm from the apex, the ProTaper Gold group had the highest frequency of cracks and at 6 mm from the apex, the Edge taper platinum group had the highest frequency of cracks. There was no significant difference in the frequency of dentin cracks between ProTaper Gold and Edge taper platinum groups in any of the sections. Conclusion: Both ProTaper Gold and Edge taper platinum systems caused the formation of dentin cracks. Preparation of root canals by Edge taper platinum and ProTaper Gold rotary files causes the formation of dentin cracks to the same extent.