Hamze Faeze, Honardar Kiamars, Nazarimoghadam Kiumars
Department of Operative Dentistry, Dental School, Kerman University of Medical Sciences, Kerman, Iran.
Iran Endod J. 2011 Fall;6(4):150-4. Epub 2011 Nov 15.
Root canal preparation is an important process in endodontic therapy. Nickel-titanium (NiTi) rotary file system can be used in single length technique (simultaneous technique) without early coronal enlargement, as well as in crown-down method. The purpose of this in vitro study was to compare single length with crown-down methods' shaping ability using Mtwo NiTi files.
Fifteen acrylic-resin blocks containing simulated canals were divided into two experimental groups. In group A, single length technique was used and in group B root canals were prepared by crown-down technique. Pre- and post-preparation canals were photographed in a standardized manner and were superimposed. The inner and outer walls of canal curvature were evaluated at three points (apical, middle and coronal) to determine the greatest change. The data was statistically analyzed using the Student t-test by Statistical Analysis System (SAS) software.
Statistical analysis revealed that in group B, dentine was equally removed within the canal coronal to the curvature, whereas in group A, the inner wall was predominantly removed (P<0.01). The two groups had no significant difference at the apical and middle points of the canal curvature.
Our in vitro study revealed no significant difference between the single length method and crown-down technique using Mtwo for preparation of apical and middle portion of canal curvature.
根管预备是牙髓治疗中的一个重要过程。镍钛(NiTi)旋转锉系统可用于单长度技术(同步技术),无需早期冠部扩大,也可用于冠向下法。本体外研究的目的是比较使用Mtwo NiTi锉的单长度法和冠向下法的根管成形能力。
将15个含有模拟根管的丙烯酸树脂块分为两个实验组。A组采用单长度技术,B组采用冠向下技术预备根管。预备前和预备后的根管以标准化方式拍照并叠加。在三个点(根尖、中部和冠部)评估根管弯曲的内壁和外壁,以确定最大变化。使用统计分析系统(SAS)软件通过Student t检验对数据进行统计分析。
统计分析显示,在B组中,在根管弯曲冠部的牙本质被等量去除,而在A组中,主要是内壁被去除(P<0.01)。两组在根管弯曲的根尖和中部点没有显著差异。
我们的体外研究表明,使用Mtwo预备根管弯曲的根尖和中部时,单长度法和冠向下技术之间没有显著差异。