Retrospective Longitudinal Observation of Caries Around Restorations by QLF

Objectives: Caries around restorations (CARS) are the main reason for restoration replacement. Early identification of such lesions is important for better prognosis. The aim of this study was to assess whether surfaces that developed CARS that progressed to cavitation have a different fluorescent profile than surfaces that have restorations and no associated lesions.
Methods: Quantitative Light-induced Fluorescence (QLF) images obtained from 569 children (5-13 years) that had been consented and followed for up to 48 months as part of a longitudinal study (Ferreira Zandona et al, 2013) were assessed for presence of a restoration and no associated caries lesion as determined by visual examination using the International Caries Detection and Assessment System (ICDAS). Surfaces (n=22) that had at least 3 visits and had a restoration and ICDAS 0, but during follow-up progressed to cavitation (ICDAS>5) and a random selected equal number of surfaces (n=22) with a restoration and ICDAS 0 that presented no change at follow-up were analyzed for QLF parameters: area of change (ΔA [mm2]), fluorescence loss (ΔF [%]), and fluorescence loss integrated over area of change (ΔQ [%×mm2]).
Results: On average there were 6 visits for restored surfaces that did not progress to cavitation and 6 visits for restored surfaces that progressed to cavitation. Means and slopes (changes over time) between progressed and non-progressed sur­faces were compared using linear mixed-effects mod­els. QLF parameters: ΔF, ΔQ and ΔA significantly (p≤0.0001) increased at a faster rate for surfaces that developed CARS that progressed to cavitation (ΔF= 13.6±1.0%, ΔQ= 12.5±3.3%×mm2 and ΔA= 0.9±0.1mm2) compared to restorations with no associated lesions (ΔF= 7.4±1.0%, ΔQ= 2.1±3.2%×mm2 and ΔA= 0.2±0.1mm2).
Conclusions: Within the limitations of this study, it was possible to use QLF to assess development of CARS. Analyses of restorations with associated lesions that do not progress to cavitation is warranted.