Lesion Activity Assessment of Early Caries Using Dye-enhanced Quantitative Light- Induced Fluorescence

Abstract We aimed to determine whether dye-ehanced quantitative light-induced fluorescence (DEQLF), wherein the porous structure of carious lesions is filled in with a fluorescent dye, can be used to quantitatively and intuitively distinguish between active and inactive carious lesions. To simulate active and inactive caries, lesions were artificially formed on 126 bovine specimens. They were demineralized with 1% carbopol solution for 3 (A3), 5 (A5), and 10 days (A10). Half the specimens in each group were remineralized with 2% NaF (I3, I5, and I10). The specimens were dehydrated for 10 s and dyed with 100-µM sodium fluorescein for 10 s. Images were captured with a QLF-digital 2+ Biluminator. Fluorescence intensity of the lesions (ΔG) between the groups and absolute changes in ΔG (|ΔΔG|) between dehydration and dye penetration were compared using the independent t-test. ΔG in A3, A5, and A10 were higher than those in I3, I5, and I10 (P<0.001). In |ΔΔG| comparisons, dye penetration was 3.1-3.7 times higher than dehydration in the active group (P<0.001), and was 1.7-2.2 times lower than dehydration in I3 and I5 (P<0.05), with no significant difference in I10. DEQLF may be used to clinically evaluate early caries activity, and longitudnally monitor changes in lesion activity.