An in vitro Comparison of a Combined FOTI/Visual Examination of Occlusal Caries with Other Caries Diagnostic Methods and the Effect of Stain on Their Diagnostic Performance

The aims of this in vitro study were to compare the combination of FOTI and visual inspection to other diagnostic methods for the detection and evaluation of the depth of occlusal caries and assess the effect of stain on diagnostic performance. Five diagnostic methods (combined FOTI/Visual (CFV), Visual, FOTI, DIAGNOdent and Electrical Caries Monitor) were considered. Histological validation was performed in the 152 occlusal molar sites (111 teeth) using 350-µm sections and a stereomicroscope. The rank correlation coefficients with histology ranged from 0.42 (DIAGNOdent) to 0.66 (CFV). The area under the ROC curves (AUC) for enamel lesions ranged from 0.82 (ECM) to 0.88 (CFV) and from 0.81 (DIAGNOdent) to 0.91 (CFV) for dentine lesions. The AUC at the dentine level for CFV and FOTI were similar (p > 0.05), but the AUC for CFV was significantly greater than for visual (p < 0.001), DIAGNOdent (p = 0.005) and the ECM (p = 0.04). FOTI was found to be particularly useful for the detection of dentine lesions. The exclusion of stain and brown spot lesions improved performance for all methods. It is concluded that CFV is useful for the determination of occlusal lesion depth and that in the presence of stain and brown spot lesions different cut-off points may be required for the ECM and DIAGNOdent to identify dentine lesions.