Influence of Voxel Size and Filter Application in Detecting Second Mesiobuccal Canals in Cone-beam Computed Tomographic Images

Introduction: This study assessed the influence of voxel size and filter application in detecting second mesiobuccal (MB2) canals in cone-beam computed tomographic (CBCT) images. Methods: Using the OP300 CBCT system (Instrumentarium, Tuusula, Finland) and 3 voxel size protocols (80 mu m, 125 mu m, and 200 mu m), we scanned 40 first molars: 20 with an MB2 canal and 20 without. All molars received silver palladium pins on the palatal root, whereas the non-MB2 molars were also filled with gutta-percha. Five oral radiologists assessed the presence of an MB2 canal under 3 filter application conditions: without filter, with sharpen 1 ! filter, and with sharpen 2 ! filter. Intra-and interobserver reproducibility was evaluated using the weighted kappa index. We compared the area under the receiver operating characteristic curves with SPSS Statistics v.20.0 (IBM Corp, Armonk, NY) using 2-way analysis of variance and the Tukey post hoc test with 5% significance level. Results: Our analysis found median intra-and interobserver agreement values of 0.70 and 0.56, respectively. The 80-mu m voxel with sharpen 1 ! filter image group had the highest sensitivity, accuracy, and negative predictive values. As for specificity and positive predictive, the 80-mu m voxel group without filter application presented the highest values. The areas under the receiver operating characteristic curve were higher in the 80-mu m groups than in the 125-mu m and 200-mu m voxel size groups (P , .05). We found no differences among the filters used (P = .22) or for the filter-voxel size interactions (P = .88). Conclusions: A smaller voxel size increased the accuracy in detecting MB2 canals, whereas the enhancement filters did not. (J Endod 2021;47:1391-1397.)

Automated summary

This study showed that a smaller voxel size improved the accuracy in detecting MB2 canals, while the application of enhancement filters did not have a significant impact.