Selvaraj Harish, Krithikadatta Jogikalmat, Venkata Teja Kavalipurapu
Conservative Dentistry and Endodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, IND.
Department of Conservative Dentistry and Endodontics, Mamata Institute of Dental Sciences, Hyderabad, IND.
Cureus. 2023 Aug 27;15(8):e44183. doi: 10.7759/cureus.44183. eCollection 2023 Aug.
Aim The aim of the study was to assess the instrument deformation following the usage of the TruNatomy (Dentsply Sirona, USA) file system in extracted premolars using Scanning Electron Microscopy (SEM). Materials and Methods For the present study, 84 extracted mandibular bicuspids were selected. The teeth were divided into two groups: Group 1, TruNatomy (n=42), and Group 2, Hero Shaper (Micro Mega, France) (n=42). The samples were shaped with 0.03 taper to size 36 with TruNatomy instruments and 0.04 taper to size 30 with Hero Shaper instruments. 5 ml of 5.25% Sodium Hypochlorite (NaOCl) and 2 ml of 17% ethylenediaminetetraacetic acid (EDTA) were used for the final irrigation of root canals. The master apical file was used to instrument seven teeth samples for assessing the safety of the instruments after multiple uses and autoclaving. So, a total of six files per group was used for the analysis of any distortions, cracks or micro-fractures after instrumentation of 42 teeth, at the tip (D0) and 5 mm from the tip (D5) of the rotary file under SEM at 500x magnification. Statistical analysis To determine the significance between the groups, the Mann-Whitney U-test was applied. Results The mean surface wear of the instruments, at the tip (D0) in Group 1 was 1.2857 and in Group 2 was 1.4762. The mean spiral distortion of the instruments, at the tip (D0) in Group 1 was 1.1905 and in Group 2 was 1.4286. A statistically significant difference (P<0.05) was observed between the groups for surface wear and spiral distortion at the tip of the file (D0). There was no significant difference between groups for surface wear and spiral distortion values of the instruments at 5 mm from the tip (D5) (P>0.05). Conclusion The instrument distortion of the rotary file systems analysed was minimal following the biomechanical preparation of seven mandibular bicuspids without root curvature, using a single file. Therefore, both rotary file systems can be considered safe.
目的 本研究的目的是使用扫描电子显微镜（SEM）评估在拔除的前磨牙中使用TruNatomy（美国登士柏西诺德公司）锉系统后器械的变形情况。
材料与方法 对于本研究，选取了84颗拔除的下颌双尖牙。将牙齿分为两组：第1组，TruNatomy（n = 42），第2组，Hero Shaper（法国Micro Mega公司）（n = 42）。用TruNatomy器械将样本预备成0.03锥度至36号，用Hero Shaper器械将样本预备成0.04锥度至30号。5毫升5.25%次氯酸钠（NaOCl）和2毫升17%乙二胺四乙酸（EDTA）用于根管的最终冲洗。主尖锉用于预备7颗牙齿样本，以评估多次使用和高压灭菌后器械的安全性。因此，每组共6根锉用于分析在500倍放大倍数的SEM下，42颗牙齿预备后旋转锉尖端（D0）和距尖端5毫米处（D5）的任何变形、裂纹或微骨折情况。
统计分析 为确定两组之间的显著性差异，应用了曼-惠特尼U检验。
结果 第1组器械尖端（D0）的平均表面磨损为1.2857，第2组为1.4762。第1组器械尖端（D0）的平均螺旋变形为1.1905，第2组为1.4286。两组在锉尖端（D0）的表面磨损和螺旋变形方面存在统计学显著差异（P<0.05）。两组在距尖端5毫米处（D5）器械的表面磨损和螺旋变形值之间无显著差异（P>0.05）。
结论 在使用单个锉对7颗无牙根弯曲的下颌双尖牙进行生物力学预备后，所分析的旋转锉系统的器械变形最小。因此，两种旋转锉系统均可认为是安全的。
