Effect of Optimum Torque Reverse Motion on Torque and Force Generation during Root Canal Instrumentation with Crown-down and Single-length Techniques
Effect of Optimum Torque Reverse Motion on Torque and Force Generation during Root Canal Instrumentation with Crown-down and Single-length Techniques
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DOI：
10.1016/j.joen.2019.11.007
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发表时间：
2020-02-01
影响因子：
4.2
通讯作者：
Okiji, Takashi
中科院分区：
文献类型：
--
作者：
Kimura, Shunsuke;Ebihara, Arata;Okiji, Takashi
简介：最佳扭矩反向（OTR）运动是一种扭矩敏感的往复运动，其中当扭矩超过预定值时，电动机以逆时针90度和顺时针180度交替旋转的方式旋转。本研究旨在检查OTR运动是否有助于在采用冠下或单长度技术的镍钛旋转内固定过程中减少扭矩和力。研究方法：28个树脂块中的模拟直根管根据运动类型（OTR或连续旋转）分为2组。根据制备技术（冠向下或单长度技术，每组n = 7）进一步细分。使用扭矩/力分析装置（300 rpm，上下速度为10 mm/min）和EndoWave器械（FKG Dentaire，La-Chaux-de-Fonds，Switzerland）进行自动根管器械，以获得#25/0.06锥度。记录最大扭矩和顶端力，并采用方差分析和Bonferroni检验进行分析。结果如下：在顶部向下准备阶段（#35/0.08、#30/0.06、#25/0.06和#20/0.06），OTR运动产生的最大扭矩和向上力（代表旋入力）低于连续旋转。在根尖准备阶段（#25/0.06），与连续旋转相比，使用单长度技术时，OTR运动产生的最大顺时针和逆时针扭矩显著较低（P <.05），无论准备技术如何，最大向上力均显著较低（P <.05）。结论：在目前的实验条件下，OTR运动减少了冠向下技术的冠向下准备阶段和单长度技术的根尖准备阶段的扭矩和旋入力。
Introduction: Optimum torque reverse (OTR) motion is a torque-sensitive reciprocal motion in which the motor rotates in alternating 90 degrees counterclockwise and 180 degrees clockwise rotation when the torque exceeds a predetermined value. This study aimed to examine whether OTR motion contributes to torque and force reduction during nickel-titanium rotary instrumentation with the crown-down or single-length technique. Methods: Twenty-eight simulated straight canals In resin blocks were divided into 2 groups according to the type of motion (OTR or continuous rotation). The groups were further subdivided according to the preparation technique (crown-down or single-length technique, n = 7 each). Automated root canal instrumentation was performed with a torque/force analyzing device (300 rpm, up-and-down speed of 10 mm/min) and EndoWave instruments (FKG Dentaire, La-Chaux-de-Fonds, Switzerland) to size #25/0.06 taper. Maximum torque and apical force were recorded and analyzed with analysis of variance and the Bonferroni test. Results: During the crown-down preparation phase (#35/0.08, #30/0.06, #25/0.06, and #20/0.06), OTR motion developed lower maximum torque and upward force (representing the screw-in force) than continuous rotation. During the apical preparation phase (#25/0.06), OTR motion generated significantly lower maximum clockwise and counterclockwise torque (P < .05) when the single-length technique was used and significantly lower maximum upward force regardless of the preparation technique (P < .05) compared with continuous rotation. Conclusions: Under the present experimental conditions, OTR motion reduced both torque and screw-in force during the crown-down preparation phase of the crown-down technique and during the apical preparation phase of the single-length technique.