Accuracy in Detecting Artificial Root Resorption in Panoramic Radiography versus Tomosynthetic Panoramic Radiographs

Abstract

Introduction: The aim of this study was to compare the detection accuracy of panoramic radiography (PAN) and tomosynthetically reconstructed panoramic radiography (TPAN) for the detection of artificial external root resorption in a multiobserver approach.

Methods: Thirty-six teeth in 5 dry human mandibles were prepared with artificial root resorption by means of diamond bur defects (0.8, 1.0, and 1.2 mm). The samples were exposed in a digital panoramic radiographic unit in a predetermined appropriate position using a wax layer (6.25 mm thickness) as soft tissue scatter equivalent and a water-filled plastic bottle to mimic the absorption of the cervical spine. This resulted in 5 panoramic radiographs and 5 tomosynthetically reconstructed panoramic radiographs, which were evaluated by 13 observers regarding the visibility of artificial root resorption by means of a 5-point confidence scale. Seven of these observers repeated the process after a minimum interval of 30 days. A receiver operating characteristic analysis was conducted with the area beneath the receiver operating characteristic curves (Az) as the main accuracy parameter. Inter- and intrarater reproducibility were calculated by means of the intraclass coefficient using a 2-way random effects model.

Results: The mean Az for TPAN (0.76; median = 0.77; range, 0.70-0.85) was slightly yet significantly higher (P < .05, Wilcoxon test) than for PAN (0.75; median = 0.75; range, 0.69-0.82). The Az values for both methods were highest in the premolar and lowest in the molar region. The mean sensitivity for TPAN was 0.54 (specificity = 0.96) and 0.50 (specificity = 0.96) for PAN. Intraclass coefficient values indicated that intra- (PAN: mean = 0.53 ± 0.088; TPAN: mean = 0.55 ± 0.102; P < .05,Wilcoxon test) and interrater (PAN: mean = 0.47 [0.43-0.51], TPAN: mean = 0.47 [0.42-0.51]) reproducibility were both moderate.

Conclusions: From our ex vivo study, we observed slightly higher accuracy in the detection of artificial root resorption from tomosynthetically reconstructed panoramic radiographs compared with conventional digital panoramic radiographs.

Keywords: Detection accuracy; external root resorption; panoramic radiography; receiver operating characteristics (ROC-) analysis; tomosynthesis.