Purpose: To evaluate if using the laser fluorescence (LF) device improves the detection of early or more advanced occlusal caries lesions in primary teeth. Materials and Methods: A total of 181 occlusal sites in primary teeth were assessed by one examiner using DIAGNOdent. The same examiner and a second examiner evaluated 72 of the sites again to assess intra- and inter-examiner reproducibility. After histological validation, lesions were divided at three thresholds according to the lesion depth: outer half of the enamel (D1), inner half of the enamel (D2) and dentine (D3). The sensitivity, specificity, accuracy and area under ROC curve were calculated for cut-off points for the sample considering the aforementioned thresholds. The parameters were compared using chi-square test and by comparison between unpaired ROC curves. Results: The overall LF performance was better at dentine threshold than at enamel threshold. The higher specificity was found at D3 and D2, and higher accuracy at D3 (P < 0.001). The intra- and inter-examiner agreements were classified as good or excellent for all thresholds. Conclusions: The LF device performs better at the dentine threshold than at the enamel threshold. This method does not perform well in detecting initial enamel caries lesions.

Keywords: dental caries, early detection, laser fluorescence, occlusal surface, primary teeth