Cutoff fluorescence loss for the recovery of incipient carious lesions after fluoride application in primary teeth: A clinical study

Purpose: Early detection and diagnosis of incipient caries are the keys to achieving a favorable prognosis. Monitoring of pathological changes based on clinical evidence leads to an accurate prognosis. Therefore, this clinical study investigated changes in minerals of incipient carious lesions using quantitative light-induced fluorescence-digital (QLF-D) after applying professional fluoride treatment to children, with improvement of the lesion severity assessed based on the fluorescence loss (ΔF) value obtained using QLF-D. Methods: This study examined 90 incipient enamel lesions on the primary teeth of 27 children aged between 4 and 10 years. QLF-D images were obtained before and after the application of 1.23% acidulated phosphate fluoride gel for 1 min, and the ΔF values at 0 and 4 weeks (ΔF₍₀₎ and ΔF₍₄₎, respectively) and the recovery rates (R_ΔF) of the lesions were evaluated. Receiver operating characteristic curve analysis was used to calculate the cutoff ΔF₍₀₎ value at which recovery of the lesion with fluoride treatment remained feasible. Results and conclusion: The recovery patterns of ΔF 4 weeks after fluoride application differed depending on the ΔF₍₀₎ values. The incipient lesions with ΔF₍₀₎ values of less than –13.00 recovered 4 weeks after fluoride application (P < 0.001) and had an average R_ΔF value of 19.27%. The results indicate that a ΔF₍₀₎ cutoff value can be determined for predicting the effects of remineralization after fluoride application and quantitative prognostic data can be provided to patients.