OBJECTIVES: To compare two quantitative assessment methods - visual-tactile examination and fluorescence measurement - for detecting of initial caries lesions in adolescents undergoing treatment with a multibracket appliance (MB). MATERIALS AND METHODS: This study included 28 subjects (14 males, 14 females), treated with MB in both the maxilla and mandible. Data collection occurred at three times points: prior to treatment (T0), six months after MB insertion (T1), and one year post-insertion (T2). The Enamel Decalcification Index (EDI
0-3 scale) and quantitative light-induced fluorescence (QLF) were employed for assessment. RESULTS: At T0, four subjects (14%) exhibited no lesions, while only two (7%) remained lesion-free at T1, and again at T2. The kappa coefficient for agreement between the two diagnostic methods across all time points was 0.71. CONCLUSIONS: Both the QLF and EDI methods yielded similar results, with only minor discrepancies. To determine the most appropriate method for each individual case, considerations of cost, benefit and time should be made. CLINICAL RELEVANCE: The similarity in outcomes for the QLF and EDI methods indicates that both diagnostic methods are effective and reliable. However, QLF may be prone to interference, which must be accounted for during its application.