Accuracy of Digital Subtraction Radiography for the detection of secondary caries in permanent molars(in vitro study)

Due to the limitations of conventional radiography in the diagnosis of secondary caries. The purpose of this study was to assess the efficacy of Digital Subtraction Radiography in detection of secondary caries.

This Diagnostic in-vitro study was conducted on 40 healthy permanent molars stored in 10% formalin solution. Eighty standard CL. II cavities were prepared on mesial and distal surfaces of sample teeth and were restored using amalgam restorations. Teeth were fixed in XCP Film holder with Putty and initial digital images were taken of each tooth and were stored in a memory device. Cavities for secondary caries were created in gingival walls of each tooth by a no. 1 round bur to a depth of 1 mm. and were restored by red wax. The images are reviewed by experts and the results were analyzed of using statistical analysis software SPSS (16).

The positive predictive value (PPV) and negative predictive vale (NPV)، sensitivity and specificity،in the mesial surface were 71. 6%،75. 4%، 69. 6% and 77. 2% respectively and 77%، 87%، 86%، 79. 4% in the distal surface. The diagnostic error rate in the mesial surface (26. 2%) was higher compared to the distal surface. (17. 4%)، The difference was is statistically significant. (p <0/001)

The results of this study showed that DSR can be useful in the evaluation of secondary caries.