Thompson S A, Dummer P M
Department of Restorative Dentistry, University of Wales College of Medicine, Cardiff, UK.
Int Endod J. 1998 Jul;31(4):268-74. doi: 10.1046/j.1365-2591.1998.00152.x.
The aim of this laboratory based study was to determine the shaping ability of Quantec Series 2000 nickel-titanium rotary instruments in simulated root canals. A total of 40 canals with four different shapes in terms of angle and position of curve were prepared with Quantec Series 2000 instruments using the technique recommended by the manufacturer. Part 2 of this report describes the efficacy of the instruments in terms of prevalence of canal aberrations, the amount and direction of canal transportation and overall post-operative shape. Pre- and post-operative images of the canals were taken using a video camera attached to a computer with image analysis software. The pre- and post-operative views were superimposed to highlight the amount and position of material removed during preparation. Twenty-one zips and elbows were created during preparation with a significant difference (P < 0.005) between canal shapes in terms of the incidence of aberrations. Four perforations were created, with significant differences (P < 0.005) between the canal shapes; three ledges were also created but no danger zones. Highly significant differences (P < 0.001) were apparent between the canal shapes in total canal width at specific points along the canal length and in the amount of resin removed from the inner and outer aspects of the curve. Canal transportation at the end-point of preparation was most frequently directed towards the outer aspect of the curve, and without exception in canals with 40 degrees curves. At the beginning of the curve, transportation became more evenly balanced between the inner and outer aspect of the curve, although predominated towards the outer. Transportation was generally directed towards the outer at the orifice, especially in canals with 40 degrees curves. Mean absolute transportation at the various measurement points was less than 0.11 mm; significant differences occurred between canal shapes at the end-point of preparation (P < 0.0001), at the zips (P < 0.005), at the apex (P < 0.0001) and beginning of the curve (P < 0.05) and at the orifice (P < 0.0001). Under the conditions of this study, Quantec Series 2000 rotary nickel-titanium instruments created a relatively large number of aberrations including four perforations. The aberrations were created by the larger instruments implying that these should be used with caution at the full working distance. Scanning electron micrographs of these instruments revealed sharp instrument tips which appeared likely to predispose to transportation and the creation of defects along the outer aspect of severely curved canals.
这项基于实验室的研究旨在确定Quantec 2000系列镍钛旋转器械在模拟根管中的塑形能力。使用制造商推荐的技术，用Quantec 2000器械对总共40条具有四种不同角度和弯曲位置形状的根管进行预备。本报告的第二部分从根管形态异常的发生率、根管偏移的量和方向以及总体术后形态方面描述了这些器械的效果。使用连接到装有图像分析软件的计算机的摄像机拍摄根管的术前和术后图像。将术前和术后视图叠加，以突出预备过程中去除材料的量和位置。预备过程中形成了21处拉链状和肘状弯曲，根管形状在形态异常发生率方面存在显著差异（P < 0.005）。形成了4处穿孔，根管形状之间存在显著差异（P < 0.005）；还形成了3处台阶，但未形成危险区。在沿根管长度的特定点处的根管总宽度以及从弯曲的内、外侧面去除的树脂量方面，根管形状之间存在极显著差异（P < 0.001）。预备终点处的根管偏移最常朝向弯曲的外侧，40度弯曲的根管无一例外。在弯曲起始处，根管偏移在弯曲的内、外侧面之间变得更加均匀平衡，尽管仍以外侧为主。在根管口处，偏移通常朝向外侧，尤其是40度弯曲的根管。各测量点处的平均绝对偏移小于0.11毫米；在预备终点（P < 0.0001）、拉链状处（P < 0.005）、根尖处（P < 0.0001）、弯曲起始处（P < 0.05）和根管口处（P < 0.0001），根管形状之间存在显著差异。在本研究条件下，Quantec 2000系列镍钛旋转器械产生了相对较多的形态异常，包括4处穿孔。这些形态异常是由较大的器械造成的，这意味着在全工作长度使用时应谨慎。这些器械的扫描电子显微镜照片显示器械尖端尖锐，这似乎易于导致偏移以及在严重弯曲根管的外侧形成缺陷。
