Bapna Pradeep, Ali Afzal, Makandar Saleem D, Nik Abdul Ghani Nik Rozainah, Metgud Sandeep
Conservative Dentistry and Endodontics, Pacific Dental College and Hospital, Udaipur, IND.
Conservative Dentistry and Endodontics, School of Dental Sciences, Health Campus Universiti Sains Malaysia, Kubang Kerian, MYS.
Cureus. 2023 Jan 26;15(1):e34247. doi: 10.7759/cureus.34247. eCollection 2023 Jan.
To compare the effect of different tapers of the K3XF file system on the fracture resistance of endodontically treated mandibular premolars obturated with a three-dimensional (3-D) obturation system.
For the study, 80 freshly extracted human mandibular premolars with single well-developed roots without any curvatures were taken and the tooth roots were wrapped in a single layer of aluminum foil, and they were placed vertically in a plastic mold filled with self-curing acrylic resin. The access was opened, and working lengths were determined. The canals were instrumented keeping an apical size of #30 by different taper rotary files: Group 1: un-instrumented (control group), Group 2: 30/.04, Group 3: 30/.06, Group 4: 30/.08 K3XF file system, and teeth were obturated using a 3-D obturation system, and access cavities were filled using composite. Both experimental and control groups were subjected to fracture load using a conical steel tip (0.5mm) attached to a universal testing machine to record force applied in newton until root fracture.
Root canal instrumented groups showed lower fracture resistance than the uninstrumented group.
Hence it could be concluded that endodontic instrumentation with increased taper rotary instruments caused a decrease in fracture resistance of the teeth, and biomechanical preparation of root canal system with rotary or reciprocating instruments caused a significant decrease in fracture resistance of endodontically treated teeth (ETT), thereby decreasing their prognosis and long-term survival.
比较K3XF根管系统不同锥度对采用三维（3-D）充填系统充填的根管治疗后下颌前磨牙抗折性能的影响。
本研究选取80颗新鲜拔除的单根且无任何弯曲、发育良好的人下颌前磨牙，将牙根用单层铝箔包裹，垂直放置于装有自凝丙烯酸树脂的塑料模具中。开髓，确定工作长度。使用不同锥度的旋转锉将根管预备至根尖尺寸为#30：第1组：未预备（对照组），第2组：30/.04，第3组：30/.06，第4组：30/.08 K3XF根管系统，然后使用3-D充填系统对牙齿进行充填，并用复合树脂充填髓腔。实验组和对照组均使用连接到万能试验机上的锥形钢尖（0.5mm）施加抗折载荷，记录以牛顿为单位施加的力直至牙根折断。
根管预备组的抗折性能低于未预备组。
因此可以得出结论，使用锥度增加的旋转器械进行根管预备会导致牙齿抗折性能下降，使用旋转或往复器械对根管系统进行生物力学预备会导致根管治疗后牙齿（ETT）的抗折性能显著下降，从而降低其预后和长期存活率。
