Longitudinal analyses of early lesions by fluorescence: an observational study

Previous caries experience correlates to future caries risk; thus, early identification of lesions has importance for risk assessment and management. In this study, we aimed to determine if Quantitative Light-induced Fluorescence (QLF) parameters--area (A [mm(2)]), fluorescence loss (F [%]), and Q [% × mm(2)]--obtained by image analyses can predict lesion progression. We secured consent from 565 children (from 5-13 years old) and their parents/guardians and examined them at baseline and regular intervals over 48 months according to the International Caries Detection Assessment System (ICDAS), yearly radiographs, and QLF. QLF images from surfaces with ICDAS 0/1/2/3/4 at baseline that progressed (N = 2,191) to cavitation (ICDAS 5/6) or fillings and surfaces that did not progress to cavitation/fillings (N = 4,141) were analyzed independently for A, F, and Q. Linear mixed-effects models were used to compare means and slopes (changes over time) between surfaces that progressed and those that did not. QLF A, F, and Q increased at a faster rate for surfaces that progressed than for surfaces that did not progress (p = .0001), regardless of type of surface or baseline ICDAS score. AUC for ICDAS ranged from 0.65 to 0.80, but adding QLF information improved AUC (0.82-0.87, p < .0005). We concluded that faster changes in QLF variables can indicate lesion progression toward cavitation and be more clinically relevant than actual QLF values.