Central Interdisciplinary Ambulance in the School of Dentistry, University of Münster, Münster, Germany.
Int Endod J. 2019 Jan;52(1):94-104. doi: 10.1111/iej.12980. Epub 2018 Jul 16.
To assess the real-time dynamic torque values and axial forces during preparation of straight root canals using three different endodontic motors and hand preparation.
Sixty maxillary incisors were divided into four homogeneous groups (n = 15). After glide path establishment (size 20) the root canals were prepared to an apical size 40 using the rotary NiTi system F6 SkyTaper. Motors (DentaPort ZX OTR, EndoPilot and VDW.silver) were set to 'auto-torque-reverse' mode and DentaPort ZX was set to its specific OTR mode (optimum torque reverse). One group served as a control using manual balanced-force canal preparation with K-Flexofiles. Teeth were embedded in resin and fixed in a multi-component sensor measuring axial and torsional load during active instrumentation with 50 Hz. Preparation time was also recorded. Data were statistically analysed using the Kruskal-Wallis test.
The maximum axial forces (peak) and both peaks of dynamic clockwise and counter-clockwise torque did not differ significantly when using the three different motors despite different gear ratios and pre-settings. Only the VDW.silver motor exceeded the torque values during the use of 30 instruments (3.3%). The Morita OTR motor exceeded the maximum intrinsic torque set at 1.0 Ncm in approximately 53% of cases. The larger tapered F6 SkyTaper instruments (size 20, .06 taper and size 30, .06 taper) created significantly higher torque values (P < 0.0001). Manual instrumentation created significantly lower torque levels and higher axial values compared to rotary instrumentation (P < 0.0001) and was significantly more time consuming (P < 0.0001).
Manual preparation was associated with significantly lower torque peaks compared to rotary instrumentation. The three motors remained well within the safety torque values of the instruments.
评估使用三种不同根管马达和手动预备直根管时的实时动态扭矩值和轴向力。
60 颗上颌中切牙分为四组（n=15）。建立滑道法（20 号）后，使用镍钛旋转系统 F6 SkyTaper 预备至 40 号根尖。马达（DentaPort ZX OTR、EndoPilot 和 VDW.silver）设置为“自动扭矩反转”模式，DentaPort ZX 设置为其特定的 OTR 模式（最佳扭矩反转）。一组作为使用 K 型 Flexo 锉手动平衡力根管预备的对照。将牙齿嵌入树脂中，并用多组件传感器固定，在 50 Hz 下进行主动器械操作时测量轴向和扭转负荷。记录预备时间。使用 Kruskal-Wallis 检验对数据进行统计学分析。
尽管齿轮比和预设不同，但使用三种不同的马达时，最大轴向力（峰值）和顺时针和逆时针动态扭矩的两个峰值没有显著差异。只有 VDW.silver 马达在使用 30 个器械时（3.3%）超过了扭矩值。Morita OTR 马达在大约 53%的情况下超过了设定为 1.0 Ncm 的最大固有扭矩。较大的锥形 F6 SkyTaper 器械（20 号，0.06 锥度和 30 号，0.06 锥度）产生的扭矩值显著更高（P<0.0001）。与旋转器械相比，手动器械产生的扭矩水平显著更低，轴向力更高（P<0.0001），且耗时显著更长（P<0.0001）。
与旋转器械相比，手动预备时的扭矩峰值明显较低。三种马达均在器械的安全扭矩值范围内。
