Fan Wei, Fan Bing, Gutmann James L, Fan Mingwen
Key Lab for Oral Biomedical Engineering of Ministry of Education, Endodontic Center, School & Hospital of Stomatology, Wuhan University, Wuhan, China.
J Endod. 2008 Oct;34(10):1187-90. doi: 10.1016/j.joen.2008.06.013.
The purpose of this study was to investigate the ability of digital subtraction radiography (DSR) to reveal anatomic features of C-shaped canal systems in mandibular second molars with the aid of an intraradicular contrast medium. Thirty mandibular second molars with fused roots were collected and stored in 10% formalin solution. After being scanned with microcomputed tomography (micro CT) 20 and reconstructed, the root canals were mechanically and chemically cleaned of their pulp tissue. Buccal-lingual digital radiographic (radiovisiography [RVG]) images were taken with mandibular bone plates for each tooth. After the introduction of contrast medium into canals, RVG images were taken again in the same way as before. The digital images taken before and after contrast medium introduction were overlapped, and the image subtraction was performed by using the 3D Doctor software (Able Software Corp, Lexington, MA). All the subtracted canal images (DSR) and reconstructed canal images based on micro CT scanning were classified into three categories (ie, type I, II, and III). The classifications based on reconstructed canal images were used as the standard to evaluate the sensitivity (Se) and specificity (Sp) of DSR classification. The results were subjected to the Wilcoxon statistical test, which showed there was no significant difference between the two classifications (p > 0.05). The DSR classification had a very high Se and Sp in all three categories. It is feasible to use the DSR technique clinically to identify anatomic features of the C-shaped canal system in mandibular second molars.
本研究的目的是借助根管内造影剂，探讨数字减影放射成像（DSR）显示下颌第二磨牙C形根管系统解剖特征的能力。收集30颗融合根的下颌第二磨牙，并保存在10%的福尔马林溶液中。经微计算机断层扫描（micro CT）扫描并重建后，对根管进行机械和化学方法清理牙髓组织。为每颗牙齿拍摄带有下颌骨板的颊舌向数字放射影像（口腔数字成像系统[RVG]）图像。在将造影剂引入根管后，以与之前相同的方式再次拍摄RVG图像。将引入造影剂前后拍摄的数字图像进行叠加，并使用3D Doctor软件（Able Software Corp，列克星敦，马萨诸塞州）进行图像减法运算。所有减影后的根管图像（DSR）和基于微CT扫描重建的根管图像被分为三类（即I型、II型和III型）。以基于重建根管图像的分类作为标准，评估DSR分类的敏感度（Se）和特异度（Sp）。结果进行Wilcoxon统计检验，结果显示两种分类之间无显著差异（p>0.05）。DSR分类在所有三类中均具有非常高的Se和Sp。临床上使用DSR技术识别下颌第二磨牙C形根管系统的解剖特征是可行的。
