Vizzotto M B, Silveira P F, Arús N A, Montagner F, Gomes B P F A, da Silveira H E D
Department of Surgery and Orthopedics, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
Int Endod J. 2013 Sep;46(9):870-6. doi: 10.1111/iej.12075. Epub 2013 Feb 26.
To compare detection of the second mesiobuccal (MB2) canal in maxillary molar teeth using cone-beam computed tomography (CBCT) with different voxel sizes against conventional radiographic examination when the MB1 was unprepared, prepared and filled.
Radiographic examination and 0.2-, 0.25- and 0.3-mm CBCT (n = 89) were performed in 3 stages: S1, no first mesiobuccal (MB1) canal preparation or filling; S2, after MB1 preparation and filling; and S3, after MB1 root canal filling removal and canal repreparation. Images were analysed using the i-Cat software. After RE and CBCT acquisition in S3, all the samples were clarified to directly visualize the presence of the MB2 canal. All images were analysed by a blinded, previously calibrated examiner. Accuracy, specificity and sensitivity were compared using analysis of variance (P < 0.05 level of significance).
MB2 root canals were detected in 67% of the samples. Overall, radiographic examination was associated with lower mean accuracy values for detecting MB2 than CBCT regardless of the MB1 condition. The MB1 root canal condition did not influence MB2 detection in 0.2-mm voxel images. The presence of root fillings in the MB1 canals reduced the detection of MB2 canals, especially in the 0.3- and 0.25-mm voxel-size images (P < 0.05).
CBCT was associated with higher mean values of specificity and sensibility than radiographic examination for the detection of MB2 canals. When endodontic retreatment is necessary removal of the root filling prior to the CBCT examination eliminates artefacts, thereby permitting the use of the 0.3-mm voxel protocol that has good diagnostic performance and lower radiation dose.
比较在第一近中颊（MB1）根管未预备、已预备并充填的情况下，使用不同体素大小的锥形束计算机断层扫描（CBCT）与传统X线检查对上颌磨牙第二近中颊（MB2）根管的检测情况。
分三个阶段进行X线检查以及0.2、0.25和0.3毫米体素大小的CBCT检查（n = 89）：阶段1，未进行第一近中颊（MB1）根管预备或充填；阶段2，MB1根管预备并充填后；阶段3，MB1根管充填物去除并重新预备根管后。使用i-Cat软件分析图像。在阶段3进行根尖片和CBCT采集后，所有样本均进行清理以直接观察MB2根管的存在情况。所有图像均由一名经过预先校准的盲法检查者进行分析。使用方差分析比较准确性、特异性和敏感性（显著性水平P < 0.05）。
67%的样本中检测到MB2根管。总体而言，无论MB1情况如何，与CBCT相比，X线检查检测MB2的平均准确性值较低。在0.2毫米体素图像中，MB1根管情况不影响MB2的检测。MB1根管内存在根充物会降低MB2根管的检测率，尤其是在0.3和0.25毫米体素大小的图像中（P < 0.05）。
对于MB2根管的检测，CBCT的特异性和敏感性平均值高于X线检查。当需要进行根管再治疗时，在CBCT检查前去除根充物可消除伪影，从而允许使用具有良好诊断性能和较低辐射剂量的0.3毫米体素方案。
