Performance Assessment of Smartooth, a Novel Laser-Based Caries Detection Device, Compared with Conventional Methods in Primary Molars: An Ex Vivo Study

This study aimed to evaluate and compare the diagnostic performance of DIAGNOdent pen (LF pen) and Smartooth (SM) in detecting occlusal and smooth surface caries in extracted primary molars. The device-specific optimal cut-off values were determined, and their clinical applicability was assessed using microcomputed tomography (micro-CT) as the gold standard. Overall, 79 extracted primary molars were evaluated ex vivo. The caries-detection methods included visual examination, LF pen, and SM. The optimal cut-off values were calculated from the receiver operating characteristic curves using Youden’s index; diagnostic performance was also measured. For occlusal surfaces, SM showed higher specificity than the LF pen, whereas the LF pen showed higher accuracy; for enamel caries (D1), SM also had the highest sensitivity and Az. For smooth surfaces, the LF pen showed the highest sensitivity for D1, while sensitivity did not differ significantly for dentin caries (D2); specificity and accuracy for D2 were highest for visual examination, with the LF pen exceeding SM in accuracy. SM showed high Az for D1; agreement varied by surface and depth and was lower than visual examination for occlusal D1. All optimal cut-off values were lower than the manufacturer’s recommendations. Furthermore, LF pen and SM provide specificity and sensitivity, respectively, and may be selectively used based on the lesion and diagnostic objective. These device-specific tendencies are surface- and depth-specific and are hypothesis-generating rather than establishing clinical roles; clinical utility will require prospective in vivo pediatric validation.