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The objective of this study was to determine if changes in fluorescence intensity during dehydration could be used to assess white-spot status with quantitative light-induced fluorescence (QLF). 120 human sound polished enamel specimens, 4E4E2.5 mm, were used. Sound, demineralized, and remineralized enamel images were acquired using QLF at 1-second intervals up to 15 s. During image acquisition, the specimens were dehydrated with compressed air. Specimens were divided into 2 groups and demineralized chemically for 48 h (group-48) or 96 h (group-96). Specimens were subsequently divided into 2 groups and remineralized with a pH-cycling model [Schemehorn et al., J Dent Res 1994;73:241] with 250 (group-250) or 1,100 ppm F (group-1,100) as NaF. Fluorescence intensity (FI) of sound (FIS), demineralized (FID) and remineralized (FIR) enamel was determined with QLF. Surface microhardness was performed initially and after demineralization (SMHD) and remineralization (SMHR). One thin section was obtained for transverse microradiography to assess integrated mineral loss for de- (IMLD) and remineralization (IMLR). FIS did not change during dehydration. FID and FIR decreased during the first few seconds of dehydration; however, the effect was much more pronounced for the demineralized enamel. The change in FI per second (.FIS) - FI1-FI0, (FI3-FI0)/3 and (FI5-FI0)/5 - and .M = IMLD-IMLR was determined. Analyses were performed using ANOVA. Group A was lower than group B in SMHD and in IMLD (p = 0.0001). Concerning SMHR and .M, group-250 was lower than group-1,100 (p = 0.0001). Regarding FID, after 1 s of dehydration, there was no difference in .FIS between groups (p = 0.99); however, after 3 and 5 s, there was a difference between groups (p = 0.0001). For FIR, there was a difference between groups after 1, 3 and 5 s (p = 0.0001). It can be concluded that .FIS may be used to assess whitespot status using QLF. |