Rhodes S Craig, Hülsmann Michael, McNeal Sandre F, Beck Preston, Eleazer Paul D
Department of Endodontics, University of Alabama School of Dentistry, Birmingham, Alabama, USA.
Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2011 May;111(5):659-67. doi: 10.1016/j.tripleo.2010.11.021. Epub 2011 Mar 16.
The aim of the present study was to assess several parameters related to the clinical usage of 2 root canal preparation instruments: Vortex .06 rotary nickel-titanium instruments, and Safesiders reciprocating stainless steel instruments.
Fifty extracted mandibular molars with mesial root canal curvatures between 20° and 50° were divided into 2 groups and embedded in acrylic resin inside a modified Bramante muffle system. All root canals were prepared to ISO size 40 using either Vortex .06 rotary nickel-titanium-instruments in a low-torque motor or Safesiders stainless steel instruments in a proprietary reciprocating handpiece. The following parameters were evaluated: straightening of curved root canals, working safety issues (perforations, instrument breakages, canal blockages, loss of working length), postpreparation root canal cross-section, and working time.
The Vortex .06 instruments maintained canal curvatures well, with the mean degree of straightening recorded as 0.72°. Safesiders instruments demonstrated significantly more canal straightening, with the mean degree of straightening recorded as 15.5°. More than 90% of the root canals prepared with the Vortex .06 instruments resulted in a round or oval cross-section, whereas the Safesiders instruments produced round or oval cross-sections 60% of the time. Neither of the 2 instruments could effectively prepare 100% of the root canal circumference. The area of dentin removed and the remaining dentin thicknesses from each region were similar for the 2 groups. Six procedural incidents were recorded for the Vortex .06 group, compared with 19 for the Safesiders group. There were no instrument fractures recorded in either group. Mean working time was significantly shorter for Vortex .06 (279 s) than for Safesiders (324 s).
Vortex .06 maintained the original root canal curvatures well, whereas Safesiders instruments demonstrated significant straightening and irregular preparation shapes when used in sizes larger than ISO 20. Preparation of the complete circumference of the root canal was not possible with either system. Fewer procedural errors occurred with the Vortex instruments.
本研究旨在评估与两种根管预备器械临床使用相关的几个参数：Vortex.06旋转镍钛器械和Safesiders往复式不锈钢器械。
选取50颗近中根管弯曲度在20°至50°之间的拔除下颌磨牙，分为两组，嵌入改良Bramante马弗炉系统内的丙烯酸树脂中。所有根管均使用低扭矩马达中的Vortex.06旋转镍钛器械或专用往复式手机中的Safesiders不锈钢器械预备至ISO 40号。评估以下参数：弯曲根管的伸直情况、工作安全性问题（穿孔、器械折断、根管堵塞、工作长度丧失）、预备后根管横截面以及工作时间。
Vortex.06器械能很好地保持根管弯曲度，记录的平均伸直度为0.72°。Safesiders器械显示出明显更多的根管伸直，记录的平均伸直度为15.5°。用Vortex.06器械预备的根管中，超过90%形成圆形或椭圆形横截面，而Safesiders器械有60%的时间产生圆形或椭圆形横截面。两种器械均无法有效预备100%的根管圆周。两组从每个区域去除的牙本质面积和剩余牙本质厚度相似。Vortex.06组记录到6起操作事件，而Safesiders组为19起。两组均未记录到器械折断。Vortex.06的平均工作时间（279秒）明显短于Safesiders（324秒）。
Vortex.06能很好地保持原始根管弯曲度，而Safesiders器械在使用大于ISO 20号的尺寸时显示出明显的伸直和不规则的预备形状。两种系统均无法预备根管的完整圆周。Vortex器械发生的操作错误较少。
