Walsh C L, Messer H H, ElDeeb M E
School of Dentistry, University of Minnesota, Minneapolis.
J Endod. 1990 Jun;16(6):273-8. doi: 10.1016/s0099-2399(06)81629-8.
The purpose of this study was to evaluate the effect of instrumenting root canals using an ultrasonic device (Enac) at different power levels on the prepared canal shape and instrumentation time, and to compare these results with those obtained using a standardized hand instrumentation technique. The mesial canals (120) of 60 human mandibular first and second molars were randomly assigned to one of six groups. In groups A through D, the canals were instrumented using the Enac ultrasonic unit at different power settings (1, 2, 3, and 5, respectively). Group E was hand instrumented. Group F served as uninstrumented controls. The roots were then sectioned horizontally and the canal shapes examined, as was the mesiodistal canal diameter as it relates to the external root surface. Instrumentation time for each group was recorded. Ultrasonic instrumentation at the different power settings was significantly faster than hand instrumentation (p less than 0.001). However, the difference between the different power levels was not significant. There were no significant differences between the different groups as to the effect on the prepared canal shape. The only problem arising from using the Enac at a power level more than the recommended (5) was the greater tendency to break size #15 files during instrumentation. Using the Enac at power level 3 provided satisfactory instrumentation capability with minimal risk of file breakage.
本研究的目的是评估使用超声设备（Enac）在不同功率水平下对根管进行预备时，其对根管预备形态和预备时间的影响，并将这些结果与使用标准化手动预备技术获得的结果进行比较。将60颗人类下颌第一和第二磨牙的近中根管（120个）随机分为六组。在A组至D组中，使用Enac超声设备在不同功率设置下（分别为1、2、3和5）对根管进行预备。E组采用手动预备。F组作为未预备的对照组。然后将牙根水平切片，检查根管形态，以及与牙根外表面相关的近远中根管直径。记录每组的预备时间。不同功率设置下的超声预备明显快于手动预备（p<0.001）。然而，不同功率水平之间的差异不显著。不同组在对预备根管形态的影响方面没有显著差异。使用超过推荐功率水平（5）的Enac时出现的唯一问题是在预备过程中#15号锉折断的倾向更大。在功率水平3下使用Enac可提供令人满意的预备能力，且锉折断的风险最小。
