RESUMO
OBJECTIVES: To evaluate the performance of the laser fluorescence device (DIAGNOdent) for detection and quantification of smooth-surface caries lesions in primary teeth. METHODS: Seventy-seven approximal surfaces with no caries or with white spot caries lesions without cavitation was selected from 51 primary molars. Laser fluorescence readings were performed and the site of higher value in each surface was indicated. After the readings, the surfaces were cut and the samples were destined for histopathological and cross-sectional microhardness evaluation. ROC analysis was conducted and the area under the ROC curve and the best cut-off points were obtained at D1, D2 and D3 thresholds. With these cut-off values, the sensitivity, specificity and accuracy were calculated at these thresholds. The regression lines of laser fluorescence readings as function of lesion extension, lesion depth and cross-sectional microhardness values were plotted and the Pearson correlation coefficients were obtained. RESULTS: The best DIAGNOdent performance was obtained at D3 threshold (A(z)=0.90) and the worst performance was achieved at D1 threshold (A(z)=0.82). The correlation was better between the laser fluorescence readings and lesion depth obtained in polarized light microscope examination (r=0.78), than that obtained with the microhardness values (r=-0.57). CONCLUSION: The laser fluorescence shows a good performance to predict caries lesions extension. Device presents a better correlation with the lesion depth than with mineral loss in smooth-surface caries lesions.