A clinical comparison of extraoral panoramic and intraoral radiographic modalities for detecting proximal caries and visualizing open posterior interproximal contacts.

Abstract

The purpose of this study was to compare extraoral panoramic bitewings (BWs) to intraoral photostimulable phosphor (PSP) plate BWs for the detection of proximal surface caries and to establish if there was any difference between extraoral BWs, intraoral BWs and panoramic radiographs in visualizing open posterior interproximal contacts. Extraoral panoramic and intraoral BW images were acquired on each of 20 patients, resulting in 489 total non-restored, readable surfaces that were evaluated by 4 observers. The ANOVA analysis to determine diagnostic variability between and within each subject was utilized. The surfaces included in the study extended from the distal of each canine to the last posterior contact in each arch with non-readable proximal surfaces excluded (i.e.surfaces where over half the enamel layer was overlapped or where those surfaces were not visible in one or both modalities). The statistical analysis indicated that the overall mean area under the receiver operating characteristic curves across all observers for the intraoral BWs and extraoral panoramic BWs were 0.832 and 0.827, respectively, and the difference of 0.005 was not significant at p = 0.7781. The percentage of non-readable proximal surfaces across the three modalities was 4.1% for intraoral BWs, 18.3% for extraoral panoramic BWs and 51.5% for the standard panoramic images. The investigators concluded there was no significant difference in posterior proximal surface caries detection between the modalities. Extraoral panoramic BWs were much better than panoramic radiographs in visualizing open posterior interproximal contacts, 81.7% vs 48.5%, but below the 95.9% value for intraoral BWs.