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

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.

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.

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.

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.