Maki Keiichiro, Ebihara Arata, Unno Hayate, Omori Satoshi, Nakatsukasa Taro, Kimura Shunsuke, Okiji Takashi
Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
Materials (Basel). 2022 Apr 7;15(8):2724. doi: 10.3390/ma15082724.
This study aimed to examine how downward loads influence the torque/force and shaping outcome of ProTaper NEXT (PTN) rotary instrumentation. PTN X1, X2, and X3 were used to prepare J-shaped resin canals employing a load-controlled automated instrumentation and torque/force measuring device. Depending on the torque values, the handpiece was programmed to move as follows: up and down; downward at a preset downward load of 1 N, 2 N or 3 N (Group 1N, 2N, and 3N, respectively; each n = 10); or upward. The torque/force values and instrumentation time were recorded, and the canal centering ratio was calculated. The results were analyzed using a two-way or one-way analysis of variance and the Tukey test (α = 0.05). At the apex level, Group 3N exhibited the least canal deviation among the three groups (p < 0.05). The downward force was Group 3N > Group 2N > Group 1N (p < 0.05). The upward force, representing the screw-in force, was Group 3N > Group 1N (p < 0.05). The total instrumentation time was Group 1N > Group 3N (p < 0.05). In conclusion, increasing the downward load during PTN rotary instrumentation improved the canal centering ability, reduced the instrumentation time, and increased the upward force.
本研究旨在探讨向下的载荷如何影响ProTaper NEXT（PTN）旋转器械的扭矩/力及塑形效果。使用PTN X1、X2和X3，通过负载控制的自动器械操作及扭矩/力测量装置来预备J形树脂根管。根据扭矩值，对手动器械进行如下编程移动：上下移动；以1 N、2 N或3 N的预设向下载荷向下移动（分别为1N组、2N组和3N组；每组n = 10）；或向上移动。记录扭矩/力值和器械操作时间，并计算根管居中率。结果采用双向或单向方差分析及Tukey检验进行分析（α = 0.05）。在根尖水平，3N组在三组中根管偏移最小（p < 0.05）。向下的力为3N组>2N组>1N组（p < 0.05）。代表旋入力的向上的力为3N组>1N组（p < 0.05）。总的器械操作时间为1N组>3N组（p < 0.05）。总之，在PTN旋转器械操作过程中增加向下的载荷可提高根管居中能力，减少器械操作时间，并增加向上的力。
