RESUMO
Background: Dental radiography is an important tool for detection of caries and digital radiography is the latest advancement in this regard. Spatial resolution is a characteristic of digital receptors used for describing the quality of images. Aim: This study was aimed to compare the diagnostic accuracy of two digital radiographic systems with three different resolutions for detection of noncavitated proximal caries. Settings and Design: Diagnostic accuracy. Materials and Methods: Seventy premolar teeth were mounted in 14 gypsum blocks. Digora® Optime and RVG Access were used for obtaining digital radiographs. Six observers evaluated the proximal surfaces in radiographs for each resolution in order to determine the depth of caries based on a 4‑point scale. The teeth were then histologically sectioned, and the results of histologic analysis were considered as the gold standard. Data were entered using SPSS version 18 software and the Kruskal–Wallis test was used for data analysis. P <0.05 was considered as statistically significant. Results: No significant difference was found between different resolutions for detection of proximal caries (P > 0.05). RVG access system had the highest specificity (87.7%) and Digora® Optime at high resolution had the lowest specificity (84.2%). Furthermore, Digora® Optime had higher sensitivity for detection of caries exceeding outer half of enamel. Judgment of oral radiologists for detection of the depth of caries had higher reliability than that of restorative dentistry specialists. Conclusion: The three resolutions of Digora® Optime and RVG access had similar accuracy in detection of noncavitated proximal caries.