Butcher Seth, Mansour Abeer, Ibrahim Mohamed
Department of Surgical Science, Division Endodontics, Marquette University, School of Dentistry, Milwaukee, USA.
Department of Endodontics, Mansoura University, Faculty of Dentistry, Mansoura, Egypt.
Eur Endod J. 2019 Feb 6;4(1):9-14. doi: 10.14744/eej.2018.06078. eCollection 2019.
This study aimed to investigate the relationship between final apical preparation size and smear layer removal in the apical third using conventional irrigation in mandibular bicuspids.
A total of 66 extracted human mandibular bicuspids with comparable root canal morphology were equally divided into five experimental groups and a control group (n=11). Based on their experimental group, samples were instrumented up to size 25, 30, 35, 40, or 45 with 0.04 taper using 2.5% sodium hypochlorite (NaOCl) as the irrigant. Final irrigation was performed with 17% EDTA followed by 2.5% NaOCl. The control group was instrumented up to size 45/.04, and was irrigated with distilled water. Samples were sectioned buc-colingually, and they were qualitatively evaluated under scanning electron microscope for efficacy in smear layer removal. The Kruskal-Wallis and Mann-Whitney U tests were employed for statistical analysis.
Statistical analysis revealed comparable removal of smear layer in the coronal and middle thirds of all experimental samples regardless of grouping. When using file size larger than 35, removal of smear layer in the apical third significantly improved (p<0.05). No significant difference was observed between 40/.04 and 45/.04.
Under the conditions of this study, using conventional irrigation, apical enlargement more than size 35/.04 is essential to enhance removal of smear layer at the apical third.
本研究旨在探讨在下颌双尖牙中使用传统冲洗方法时，最终根尖预备尺寸与根尖三分之一处玷污层去除之间的关系。
选取66颗根管形态相似的拔除人下颌双尖牙，平均分为五个实验组和一个对照组（n = 11）。根据实验组不同，样本分别使用2.5%次氯酸钠（NaOCl）作为冲洗剂，预备至25、30、35、40或45号0.04锥度的器械。最终冲洗先用17%乙二胺四乙酸（EDTA），再用2.5% NaOCl。对照组预备至45/.04号，用蒸馏水冲洗。样本沿颊舌向切片，在扫描电子显微镜下对玷污层去除效果进行定性评估。采用Kruskal-Wallis检验和Mann-Whitney U检验进行统计分析。
统计分析显示，所有实验组样本在冠部和中部三分之一处的玷污层去除情况相当，与分组无关。当使用大于35号的锉时，根尖三分之一处的玷污层去除情况显著改善（p<0.05）。40/.04号和45/.04号之间未观察到显著差异。
在本研究条件下，使用传统冲洗方法时，根尖扩大至超过35/.04号对于增强根尖三分之一处玷污层的去除至关重要。
