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The objective of this study was to compare three caries diagnosis techniques: quantitative laser-induced fluorescence (QLF I), quantitative light-induced fluorescence (QLF II), and infrared laser fluorescence (IR). Seventy-seven 3-mm diameter, human polished enamel specimens were used. Half of each specimen was demineralized for either 0, 24, 48, 72, 96, or 120 h. The specimens were then illuminated by argon laser (488 nm, 520-nm filter) and later by violet-blue light (290-450 nm, 540-nm filter). Images were captured for both QLF I and II. A standardized area of each demineralized enamel image was cut and pasted on the sound enamel image for that specimen using a graphic program (Adobe Photoshop®). These managed images were analyzed with an Inspektor QLF program. Specimens were then analyzed with an infrared laser system (DIAGNOdent). One 100-Ìm section was cut from each specimen and analyzed by transverse microradiography (TMR), which was used as the 'gold standard' for lesion analyses. The results indicated the correlations of TMR ¢Z to QLF I, QLF II, and IR were r = 0.82, 0.83, and 0.58, respectively. The correlations of TMR lesion depth to QLF I, QLF II, and IR were 0.83, 0.86, and 0.59, respectively. The correlations of QLF I to QLF II and IR were r = 0.91 and 0.54, respectively. The correlation between QLF II and IR was r = 0.57. From these results, it can be concluded that, under the conditions of this study, the ability to quantify white-spot lesions by either laser or light QLF is more predictive than by IR. |