Ahmad M
Department of Conservative Dentistry, University of Malaya, Kuala Lumpur, Malaysia.
Endod Dent Traumatol. 1991 Apr;7(2):55-8. doi: 10.1111/j.1600-9657.1991.tb00184.x.
The efficacy of two ultrasonic units in shaping curved canals in teeth were compared. Twenty teeth were instrumented using the Cavi-Endo unit at a power setting 1 using the technique recommended by the manufacturer. Another group of 20 teeth received similar treatment but were instrumented with the Enac unit. The time taken to instrument each canal was recorded. The pre- and post-instrumented radiographs of the teeth of x 10 magnification were taken using a microfocal technique. The radiographs were subjected to a subtraction technique to result in composite images of the pre- and post-instrumented shapes. The canal shape and the incidence of elbows were evaluated using various measurements taken from the radiographs. The manner the dentine was removed was similar in both groups. All canals exhibited unequal removal along the canal with more dentine being removed at the coronal end. The Enac group exhibited a higher incidence of elbows which occurred further apically than those in the Cavi-Endo group. There was no significant difference between groups in the following: time of instrumentation, amount of apical and coronal canal enlargement, apical deviation and change in width at the elbow. These findings were no different from those of another study using simulated canals.
比较了两种超声设备在对牙齿弯曲根管进行塑形时的效果。使用Cavi-Endo设备，按照制造商推荐的技术，在功率设置为1的情况下对20颗牙齿进行根管预备。另一组20颗牙齿接受类似处理，但使用Enac设备进行根管预备。记录每根根管预备所需的时间。使用微焦点技术拍摄牙齿根管预备前后放大10倍的X线片。对X线片采用减影技术，以获得根管预备前后形状的合成图像。通过对X线片进行各种测量来评估根管形状和根管袢的发生率。两组去除牙本质的方式相似。所有根管在整个根管长度上的牙本质去除量均不相等，冠端去除的牙本质更多。Enac组根管袢的发生率更高，且根管袢出现在比Cavi-Endo组更靠近根尖的位置。两组在以下方面无显著差异：根管预备时间、根尖和冠部根管扩大量、根尖偏移以及根管袢处的宽度变化。这些结果与另一项使用模拟根管的研究结果无异。
