Department of Conservative Dentistry and Endodontics, Indira Gandhi Government Dental College and Hospital, Jammu, India.
Department of Pedodontics and Preventive Dentistry, Indira Gandhi Government Dental College and Hospital, Jammu, India, Phone: +91 9419187672, e-mail:
J Contemp Dent Pract. 2020 Nov 1;21(11):1233-1237.
The present study aimed to assess the formation of microcracks in root dentin post-instrumentation with nickel-titanium (NiTi) hand and rotary file system.
Totally, 80 freshly extracted mandibular premolar teeth with single roots were chosen for this study. Access opening was performed and #10 K-file was used to attain patency of canal. All specimens were divided into four groups (each group having 20 specimens), i.e., Group I: Unprepared, Group II: NiTi hand K-files, Group III: Self-adjusting file, and Group IV: XP-Shaper single file. Complete irrigation of all the canals was performed after instrumentation. All roots were cut horizontally at three levels [apical third (3 mm), middle third (6 mm), and cervical third (9 mm)] from the apex with diamond disc. A stereomicroscope was used to view the sections under 20× magnification.
Self-adjusting file showed least number of defects with a percentage of 75% followed by XP-Shaper and NiTi hand K-files with a values of 65 and 60%, respectively. Use of hand K-files resulted in greater number of incomplete cracks (30%) and use of XP-Shaper demonstrated greater number of craze lines (15%). A statistically significant difference was found between the experimental groups in the formation of dentinal defects of root at apical third (3 mm) ( < 0.031) and middle third (6 mm) ( < 0.001), whereas the sections at cervical third (9 mm) did not show any statistically significant difference ( > 0.312).
The present study concluded that the self-adjusting file system gives promising better results in cleaning ability with minimal incidence of radicular dentin microcracks than XP-Shaper and NiTi hand K-files system.
The root dentin may unavoidably get damaged during instrumentation resulting in the formation of dentinal cracks and tiny complicated fractures, thus leading to endodontic failures. Various factors cause dentinal cracks, but the flexibility of file due to heat treatment, kinematics of the file, and the basic architecture of the file are the most significant ones. Self-adjusting file system represented satisfactory results with minimal microcracks defects.
本研究旨在评估镍钛（NiTi）手动和旋转锉系统在根管预备后牙本质微裂纹的形成。
总共选择了 80 颗具有单根的新鲜下颌前磨牙进行本研究。进行了开口操作，并使用 #10 K 锉来达到通畅。所有标本均分为四组（每组 20 个标本），即：I 组：未预备，II 组：NiTi 手动 K 锉，III 组：自调整锉，IV 组：XP-Shaper 单锉。所有器械预备后均进行彻底冲洗。所有根管均在根尖 3 毫米、6 毫米和 9 毫米处用金刚砂片水平切割，然后用体视显微镜在 20 倍放大率下观察切片。
自调整锉显示出最少的缺陷，其百分比为 75%，其次是 XP-Shaper 和 NiTi 手动 K 锉，分别为 65%和 60%。使用手动 K 锉会导致更多的不完整裂纹（30%），而使用 XP-Shaper 则会导致更多的裂纹线（15%）。在根尖 3 毫米（3 毫米）和中间三分之一（6 毫米）（<0.031）的根牙本质缺陷形成方面，实验组之间存在统计学显著差异（<0.001），而在颈三分之一（9 毫米）的切片则没有统计学显著差异（>0.312）。
本研究得出结论，自调整锉系统在清洁能力方面表现出更有前途的结果，与 XP-Shaper 和 NiTi 手动 K 锉系统相比，根牙本质微裂纹的发生率最低。
在器械预备过程中，牙本质不可避免地会受损，导致牙本质裂纹和微小复杂骨折，从而导致根管治疗失败。各种因素会导致牙本质裂纹，但文件的灵活性、文件的运动学和文件的基本结构是最重要的因素。自调整锉系统表现出令人满意的结果，微裂纹缺陷最小。
