Diagnostic Performance of a Novel Wireless Direct-Conversion Intraoral Sensor Versus CMOS and PSP Systems for Proximal Caries Detection: An Ex Vivo Study

OBJECTIVES: To compare the diagnostic accuracy of a new wireless direct-conversion digital intraoral sensor to current indirect conversion, complementary metal-oxide semiconductor (CMOS) and photostimulable phosphor (PSP) sensors for detecting proximal caries. METHODS: The sample in this ex vivo study were 28 human premolars with 21 micro-CT verified non-cavitated proximal dental carious lesions. Images were obtained using three digital intraoral systems: a wireless direct-conversion sensor, a wired indirect conversion CMOS sensor, and a PSP sensor. A custom phantom was constructed providing a limited dental arch segment comprising a molar, first premolar, and canine. The premolar was substituted and the phantom imaged using each intraoral system with (filtered) and without (raw) the application of a manufacturer-recommended enhancements, providing 168 images. Eight oral radiologists assessed the images using a five-point scale. Receiver operating characteristic analysis was performed to calculate sensitivity, specificity and the area under the curve (AUC) and compared across modalities using two-way analysis of variance (ANOVA) with post hoc Tukey's test at an a priori level of significance of 0.05. RESULTS: The AUC ranged from 0.58 to 0.73 (sensitivity range: 0.21-0.68, specificity range: 0.69-0.92). The wireless direct-conversion sensor (0.72 ± 0.06) showed diagnostic performance comparable to CMOS (0.72 ± 0.06) and superior to PSP (0.58 ± 0.07) for raw images (p < 0.001). The direct-conversion sensor without image enhancement (0.68 ± 0.18) demonstrated the highest sensitivity, whereas the PSP without image enhancement (0.21 ± 0.09) had the lowest sensitivity. Application of image enhancement improved PSP performance (0.48 ± 0.16), approximating that of the other systems. CONCLUSIONS: Based on this ex vivo study, the wireless direct-conversion and CMOS sensors demonstrated similar diagnostic performance, superior to PSP in unfiltered conditions. These findings should be interpreted in light of the ex vivo design and modest sample size.