Ghamari Maryam, Mollashahi Narges Farhad, Salarpour Mohammad, Mousavi Elnaz, Kazemian Kaveh, Moudi Ehsan, Arab Sepideh
DDS, Assistant Professor, Department of Endodontics, Faculty of Dentistry, Ghazvin University Of Medical Sciences, Ghazvin, Iran.
DDS, Associate Professor, Department of Endodontics, Faculty of Dentistry, Zahedan University Of Medical Sciences, Zahedan, Iran.
Electron Physician. 2017 Aug 25;9(8):5001-5007. doi: 10.19082/5001. eCollection 2017 Aug.
The main reason for the failure of endodontic therapy is the incomplete knowledge about the anatomical variation of root canals. One of the most important factors that leads to the failure of root canal treatment, is missed and untreated major root canals.
with respect to the complexity of mandibular incisors treatment and high prevalence of the second canal, and the possibility of the relationship between the crown size and the extra canal in these teeth, the aim of this study was to determine the relationship between crown size and root canal morphology in mandibular incisors with CBCT.
In this cross-sectional study, mandibular permanent incisors were randomly collected in Qazvin City, Iran, and were mounted in eight ternary groups on a plastic slot, using putty molding material. After preparation of Scot view, the samples were scanned by CBCT NewTom 5G. Afterward, the mesiodistal and buccolingual dimensions were measured by the software's measurement tool with a precision within tenths of a millimeter. In the next stage, a multi-planar option and 400% magnification tool of the software were utilized to study axial and cross sectional views of each tooth to determine canal type. Data were analyzed employing one-sample Kolmogorov-Smirnov, Levene, independent- samples t-test and Roc curve by SPSS version 20.
The majority of mandibular incisors have a single canal (63.9% of them had type I canal system). In addition, 36.1% of the roots had two canals, among which, type III was the most common. The mean of maximum mesiodistal and buccolingual diameters in type III was significantly bigger than that in type I (p<0.05), but the means of crown size in the two canal types were not significantly different.
Despite increase in mesiodistal and buccolingual dimension in two canal mandibular incisors with type III canal system, their crown sizes (M-D/F-L index) were not significantly different, in comparison to single canal incisors.
牙髓治疗失败的主要原因是对根管解剖变异的认识不足。导致根管治疗失败的最重要因素之一是遗漏和未处理的主要根管。
鉴于下颌切牙治疗的复杂性、第二根管的高发生率以及这些牙齿冠部大小与额外根管之间可能存在的关系，本研究旨在通过锥形束计算机断层扫描（CBCT）确定下颌切牙冠部大小与根管形态之间的关系。
在这项横断面研究中，从伊朗加兹温市随机收集下颌恒切牙，并用橡皮泥成型材料将其安装在塑料槽中，分为八个三元组。制备斯哥特视图后，使用CBCT NewTom 5G对样本进行扫描。之后，通过软件的测量工具测量近远中径和颊舌径，精度可达十分之一毫米。在下一阶段，利用软件的多平面选项和400%放大工具研究每颗牙齿的轴向和横断面视图，以确定根管类型。使用SPSS 20版软件进行单样本柯尔莫哥洛夫-斯米尔诺夫检验、莱文检验、独立样本t检验和Roc曲线分析数据。
大多数下颌切牙有单一根管（其中63.9%有I型根管系统）。此外，36.1%的牙根有两个根管，其中III型最为常见。III型根管的最大近远中径和颊舌径平均值显著大于I型（p<0.05），但两种根管类型的冠部大小平均值无显著差异。
尽管具有III型根管系统的双根管下颌切牙的近远中径和颊舌径有所增加，但与单根管切牙相比，它们的冠部大小（近远中径/颊舌径指数）无显著差异。
