Yahya A S, ElDeeb M E
J Endod. 1989 Jun;15(6):235-9. doi: 10.1016/S0099-2399(89)80215-8.
The instrumentation time, and the resulting root canal angulation change and shape after using ultrasonic, sonic, and hand instrumentation techniques were studied in the mesial canals of 55 extracted human mandibular first and second molars. After instrumentation, the roots were sectioned horizontally in the apical, middle, and coronal thirds and evaluated for shape, mesial and distal canal widths, and canal diameter. MM3000 and hand were significantly faster than the other techniques (p less than 0.005). MM3000 resulted in less angulation change than the Enac (p less than 0.005). Hand instrumentation was judged to have given the best shape (p less than 0.01).
在55颗拔除的人类下颌第一和第二磨牙的近中根管中，研究了使用超声、声波和手动器械技术后的器械操作时间、由此产生的根管角度变化和形态。器械操作后，将牙根在根尖、中部和冠部三分之一处水平切开，评估其形态、近中和远中根管宽度以及根管直径。MM3000和手动器械操作比其他技术明显更快（p小于0.005）。MM3000导致的角度变化比Enac小（p小于0.005）。手动器械操作被认为能获得最佳形态（p小于0.01）。
