Diagnostic Accuracy of Four Storage Phosphor Plate and One Film Radiography Systems for Caries Detection

Objectives: The aim of the study was to evaluate the diagnostic accuracy of four storage phosphor plate systems exposed with two exposure times and one film system for caries detection. Methods: 190 permanent teeth were radiographed using: DenOptix (Gendex, Italy), Cd-dent (Orex, Israel), Digora – blue plates (Digora-blue) and Digora – white plates (Digora-white) (Soredex, Finland) and one film system: Ektaspeed Plus (Ekta) (Kodak Company, USA). The phosphor plates were exposed twice using an exposure time of 10% and 25% of the time needed for the Ekta film. Four observers examined the radiographs for approximal and occlusal caries using a five-point confidence scale. The true diagnosis was established by histology. The diagnostic accuracy of the systems was expressed as ROC curve areas (Az). Results: Using the shorter exposure time for approximal caries, Digora-white (Az=0.68) and Ekta were significantly more accurate than DenOptix (Az=0.65), Cd-dent (Az=0.64) and Digora-blue (Az=0.65). Using the same exposure for occlusal caries, no significant difference was found between the digital systems (Az=0.76-0.77), which all were less accurate than Ekta (Az=0.81). Using the longer exposure time for approximal caries, no significant difference was found between DenOptix (Az=0.68), Digora-blue (Az=0.69), Digora-white (Az=0.69) and Ekta (Az=0.69), which all were significantly more accurate than Cd-dent (Az=0.65). Using the same exposure for occlusal caries, Digora-blue (Az=0.81) and Ekta were significantly more accurate than the other digital systems (Az=0.77-0.78). The longer exposure time resulted in significantly higher accuracy with DenOptix and Digora-blue. Conclusions: For approximal caries, only Digora-white maintained the same high accuracy as Ekta when the exposure was reduced to 10%. When the exposure was 25% DenOptix, Digora-blue and Digora-white were as accurate as Ekta. For occlusal caries using an exposure of 10%, all the digital systems were less accurate than Ekta. When the exposure was 25%, Digora-blue was as accurate as Ekta.