Lumley P J, Walmsley A D, Walton R E, Rippin J W
Department of Endodontics, College of Dentistry, University of Iowa, Iowa City.
J Endod. 1992 Dec;18(12):616-9. doi: 10.1016/S0099-2399(06)81333-6.
Endosonic files are prone to constraint; this reduces their efficiency, particularly in the apical third and in curved root canals. Precurving the file may reduce constraint, thereby improving the file's ability to debride. This investigation was undertaken to compare both straight and precurved endosonic files as to debris and smear layer removal. Thirty-six curved root canals were randomly allocated into six groups. Each group was prepared using a step-down technique, then instrumented with either a straight or precurved endosonic file of size 15, 20, or 25. The tooth roots were split and examined under the scanning electron microscope. Blind examinations were made for debris and smear layer removal and evaluation scores were analyzed using a log linear approach. The root canals instrumented with the precurved files had a significantly lower debris score than those prepared with straight files. Precurving did not affect smear layer removal. In conclusion, precurving of files decreased the amount of debris but did not affect smear layer removal.
超声根管锉易于受到限制；这会降低它们的效率，尤其是在根尖三分之一处和弯曲的根管中。预先弯曲锉可能会减少限制，从而提高锉的清创能力。进行这项研究是为了比较直的和预先弯曲的超声根管锉在清除碎屑和玷污层方面的效果。36个弯曲根管被随机分为六组。每组均采用逐步深入技术进行预备，然后用尺寸为15、20或25的直的或预先弯曲的超声根管锉进行预备。将牙根劈开并在扫描电子显微镜下检查。对碎屑和玷污层的清除进行盲法检查，并使用对数线性方法分析评估分数。用预先弯曲的锉预备的根管碎屑评分显著低于用直锉预备的根管。预先弯曲不影响玷污层的清除。总之，锉的预先弯曲减少了碎屑量，但不影响玷污层的清除。
