Effect of Different Speeds of Up-and-down Motion on Canal Centering Ability and Vertical Force and Torque Generation of Nickel-titanium Rotary Instruments
Effect of Different Speeds of Up-and-down Motion on Canal Centering Ability and Vertical Force and Torque Generation of Nickel-titanium Rotary Instruments
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DOI：
10.1016/j.joen.2018.10.002
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发表时间：
2019-01-01
影响因子：
4.2
通讯作者：
Okiji, Takashi
中科院分区：
文献类型：
--
作者：
Maki, Keiichiro;Ebihara, Arata;Okiji, Takashi
简介：本研究旨在评估上下运动的速度如何影响 ProTaper Next 旋转器械（瑞士 Ballaigues 的 Dentsply Maillefer）的根管定心能力和扭矩/力生成。方法：使用 ProTaper Next X1、X2 和 X3 仪器，使用原创的自动化根管仪器和扭矩/力分析装置，制备 21 个 1 形根管的模拟树脂根管块，上下速度设置为 10、50 和 100 mm/min（分别为低速、中速和高速组）。叠加仪器使用前和仪器后的图像，并在距离顶点 0-3 毫米处计算居中比。还记录了最大垂直力和扭矩。使用单因素方差分析和Tukey检验对结果进行统计分析。结果：在距顶点 0、0.5、1 和 2 mm 处，高速组显示出最低的对中比（即偏差最小），其次是中速组和低速组 (P < .05)。随着上下速度的增加，力值（向下和向上）趋于增加；对于 X2 和 X3 仪器，高速和/或中速组产生的值明显大于低速组 (P < .05)。对于所有仪器，高速和/或中速组产生的顺时针扭矩明显大于低速组 (P < .05)。低速组和高速组分别有 1 台和 2 台 X2 仪器发生断裂。结论：升降速度影响ProTaper Next器械的根管对中能力和应力产生。高速组表现出最好的对中能力，但往往比中速组和低速组产生更大的垂直力和扭矩。
Introduction: This study was performed to evaluate how the speed of up-and-down motion affects the canal centering ability and torque/force generation of ProTaper Next rotary instruments (Dentsply Maillefer, Ballaigues, Switzerland). Methods: Twenty-one simulated resin canal blocks with a 1-shaped canal were prepared with ProTaper Next X1, X2, and X3 instruments using an original automated root canal instrumentation and torque/force analyzing device with up-and-down speed settings of 10, 50, and 100 mm/ min (low-, medium-, and high-speed groups, respectively). Pre- and post instrumentation images were superimposed, and centering ratios were calculated at 0-3 mm from the apex. The maximum vertical force and torque were also recorded. The results were statistically analyzed using 1-way analysis of variance and the Tukey test. Results: At 0, 0.5, 1, and 2 mm from the apex, the high-speed group showed the lowest centering ratio (ie, least deviation) followed by the medium-speed and low-speed groups (P < .05). Force values (downward and upward) tended to increase as the up-and-down speed increased; with the X2 and X3 instruments, the high-speed and/or medium-speed groups generated significantly larger values than the low-speed group (P < .05). With all instruments, the high-speed and/or medium-speed groups generated significantly larger clockwise torque than the low-speed group (P < .05). One and 2 X2 instruments fractured in the low- and high-speed groups, respectively. Conclusions: The up-and-down speed affected the canal centering ability and stress generation of ProTaper Next instruments. The high-speed group showed the best centering ability but tended to generate larger vertical force and torque than the medium- and low-speed groups.