Evaluating occlusal caries using a non-destructive Micro-CT examination

This study used micro-computed tomography (Micro-CT) to evaluate occlusal dental canes nondestructively. Twenty-seven extracted molar teeth were scanned using Micro-CT, and 3-D images were reconstructed from the data. The extent of caries was evaluated from images extracted at various angles, and recorded as 2-D images. To assess the validity of Micro-CT, six teeth were randomly selected and cut approximately 100-μm-thick sections in the same plane as that evaluated using Micro-CT. The specimens were examined histologically and with contact microradiograms (CMR), The fine structure was observed using Micro-CT. The Micro-CT image was equivalent to the histological examination or CMR. In all, 78 measuring points in all of the teeth were analyzed using KaVo DIAGNOdent, a laser-based caries-detection device. Spearman's rank correlation coefficient between the DIAGNOdent score and the extent of caries was 0.70, and suggested a good correlation between DIAGNOdent and Micro-CT for examining occlusal caries. The sensitivity and specificity were calculated for DIAGNOdent using Micro-CT as the 'gold standard'. The sensitivity and specificity for enamel caries were 0.74 and 1.00, respectively. The values for dentin caries were 0.64 (sensitivity) and 0.91 (specificity). These results were similar to those of recent studies using histological examination as the gold standard. We concluded that Micro-CT is useful for non-destructive examination in the evaluation of occlusal caries.