Lee S-J, Wu M-K, Wesselink P R
Department of Conservative Dentistry, School of Dentistry, Chonbuk National University, Chonju, South Korea.
Int Endod J. 2004 Sep;37(9):607-12. doi: 10.1111/j.1365-2591.2004.00857.x.
To investigate the influence of diameter and taper of root canals on the effectiveness of ultrasonic irrigation to remove artificially placed dentine debris from simulated uninstrumented extensions in simulated root canals.
Three groups of standard canals were cut in resin blocks using either size 20, .04 taper ProFile instruments, size 20, .06 Greater Taper (GT) rotary instruments or size 20, .08 GT instruments, respectively. Each resin block was then split longitudinally through the canal, forming two halves. In one canal wall, a standard groove 4 mm in length was cut 2-6 mm from the apical end of the canal, to simulate uninstrumented canal extensions. Each groove was filled with dentine debris mixed with 2% NaOCl to simulate a situation when dentine debris accumulates in the uninstrumented canal extensions. Each canal was reassembled by joining the two halves of the resin block by means of wires and sticky wax. In each canal ultrasonic irrigation was performed for 3 min using 2% NaOCl as irrigant. Before and after irrigation, images of each half of the canal with a groove were taken using a microscope and a digital camera, after which they were scanned into a PC as TIFF images. The quantity of dentine debris in the groove was evaluated using a scoring system: the higher the score, the larger the amount of debris remaining. The score data were analysed by means of Kruskal-Wallis and Mann-Whitney U-tests.
After ultrasonic irrigation, the debris score for the size 20,.04 taper group was significantly higher than that for the size 20,.06 group (P = 0.040) and the size 20,.08 group (P = 0.006) groups. However, no significant difference was found between the size 20,.06 and the size 20,.08 groups (P = 0.320).
In simulated plastic root canals, the diameter and taper of root canal influenced the effectiveness of ultrasonic irrigation to remove artificially placed dentine debris.
研究根管直径和锥度对超声冲洗从模拟根管中人工放置的未预备根管延伸段去除牙本质碎屑效果的影响。
分别使用20号、0.04锥度的Profile器械、20号、0.06大锥度（GT）旋转器械或20号、0.08 GT器械在树脂块上制备三组标准根管。然后将每个树脂块沿根管纵向劈开，分成两半。在一侧根管壁上，从根管根尖端2 - 6毫米处切一个4毫米长的标准凹槽，以模拟未预备的根管延伸段。每个凹槽填充与2%次氯酸钠混合的牙本质碎屑，以模拟牙本质碎屑积聚在未预备的根管延伸段的情况。通过用金属丝和粘性蜡连接树脂块的两半将每个根管重新组装。在每个根管中使用2%次氯酸钠作为冲洗液进行3分钟的超声冲洗。冲洗前后，使用显微镜和数码相机拍摄带有凹槽的根管每一半的图像，然后将其作为TIFF图像扫描到计算机中。使用评分系统评估凹槽中牙本质碎屑的量：分数越高，残留的碎屑量越大。分数数据通过Kruskal - Wallis和Mann - Whitney U检验进行分析。
超声冲洗后，20号、0.04锥度组的碎屑分数显著高于20号、0.06组（P = 0.040）和20号、0.08组（P = 0.006）。然而，20号、0.06组和20号、0.08组之间未发现显著差异（P = 0.320）。
在模拟塑料根管中，根管直径和锥度影响超声冲洗去除人工放置的牙本质碎屑的效果。
