The diagnostic accuracy of cone-beam computed tomography and two-dimensional imaging methods in the 3D localization and assessment of maxillary impacted canines compared to the gold standard in-vivo readings: A cross-sectional study.

Background: Although the widespread cone-beam computed tomography (CBCT) is a diagnosing tool for impacted canines, the surgical exposure-based diagnostic accuracy of this 3D imaging modality has not been established yet. Therefore this study aimed to (1) compare the accuracy of CBCT- and 2D-based interpretations of impacted canine and its relationships with the neighbouring structures with the gold standard (GS) readings, (2) and calculate the diagnostic accuracy, sensitivity, and specificity values of the variables assessed using CBCT and 2D methods.

Material And Methods: Patients with unilateral impacted maxillary canines (IMCs) planned for surgical extraction between 2016-2018 were checked in-depth to include in this cross-sectional study. For each patient, 2D and 3D radiographic records were obtained and assessed by eight postgraduate orthodontic students. These assessments were compared with the GS readings based on surgical exposure and direct vision of the IMCs. To compare 2D- and CBCT-based assessments with the GS values, Cochran's Q tests, Friedman's tests, McNemar's, McNemar-Bowker's, and Wilcoxon tests were applied.

Results: A total of 17 patients (6 males, 11 females; mean age: 20.52±3.98 years) were randomly selected and included in this study. Significant differences were found between the CBCT-based assessments and the GS only concerning shape and bony coverage of the IMC (P=0.001 and P<0.001, respectively). On the contrary, there were significant differences between the 2D-based assessments and the GS regarding all the assessed variables except for the ankylosis and the proximity to the adjacent teeth (P=0.424, and P=0.080, respectively). CBCT-based assessments had remarkably higher values of diagnostic accuracy, sensitivity, and specificity compared to 2D-based ones.

Conclusions: The diagnostic accuracy of CBCT outperformed 2D radiography in localizing the IMC (labiopalatal, mesiodistal, and vertical location), detecting root apex development of the IMCs, and the resorption of the adjacent incisors. Although both 2D and 3D techniques showed the same ability in the diagnosis of IMCs ankylosis, the diagnostic accuracy of CBCT was superior. However, both techniques inaccurately determined the shape of the impacted canine and the bony coverage.