Conventional, digital and contrast-enhanced bitewing radiographs in the decision to restore approximal carious lesions.

The purpose of the present investigation was to compare the accuracy of treatment decisions in proximal sites using three intra-oral radiographic systems. Additionally, the impact of an automated non-linear grey-level display was evaluated. Ten observers assessed 84 surfaces on bitewing radiographs for their requirement of restorative treatment using a 6-rank confidence scale. Radiographs were taken with conventional film images (Ultraspeed), a storage phosphor plate (Digora) and a CCD system (Dexis). Additionally, the Dexis software was expanded by a contrast enhancement routine (Dexis+). The restorative treatment threshold was defined as presence of macroscopic cavitation. Regarding the areas below mean ROC curves no significant differences were detected between the groups (p>0.05). Likelihood ratios for positive test results were: 5.29 (Ultraspeed), 8.14 (Digora), 9.67 (Dexis) and 11.37 (Dexis+). The accuracy of restorative treatment decisions based on digital and conventional radiographs is comparable. If a dichotomous treatment decision was requested, the digital systems demonstrated a notable tendency towards higher likelihood of true-positive decisions.