Background: Caries detection in school oral examinations insufficient accuracy. Objective: To evaluate advantages of introducing quantitative lightinduced fluorescence-digital (QLF-D) in school oral examinations. Methods: Experiment No. 1. Early demineralized lesions in the upper and lower incisors and canines were visually inspected by three dentists and by QLF-D. The numbers of tooth planes with early demineralized lesions were compared between the methods. Experiment No. 2. Approximal demineralized lesions in molars were assessed by visual inspection, x-ray imaging, and QLF-D. The numbers of tooth planes with demineralized lesions were compared among the methods. Experiment No. 3. Plaque distribution was evaluated by QLF-D and a traditional staining method. The ratio of the diameter of plaque to tooth crown in the tooth axis direction in each method was calculated. The results were evaluated by Pearson's correlation coefficient analysis and Bland-Altman plot. Results: Experiment No. 1. The three dentists found 0.67 tooth planes on average. QLF-D found 22 tooth planes with early demineralized lesions in the same samples. Experiment No. 2. Fourteen approximal tooth planes of molars were found to have demineralized lesions by x-ray imaging. QLF-D detected 71.4% of the tooth planes out of the 14, whereas visual inspection found 7.1%. Experiment No. 3. The Pearson's correlation coefficient for the evaluations of plaque distribution between the QLF-D and traditional staining methods was 0.77 (P < 0.001). No statistically significant systematic error was found through the Bland-Altman Plot analysis. Conclusion: The results support introduction of QLF-D for use in school dental examinations.

As erosion has become one of the serious oral health problems, some fluoride-releasing dental materials have been developed to protect enamel from demineralization. The purpose of this study was to evaluate the antidemineralization effect of PRG Barrier Coat ® and FujiVII ® (fluoridereleasing dental materials). Four square windows measuring 1 mm 2 were prepared on the labial enamel surface of each bovine tooth using masking tape and nail varnish. The first and second windows were half covered by fluoride-releasing material and control material, respectively, whereas the third and fourth windows were left untreated. All windows were immersed into 0.1 M lactic acid and 6wt% CM-cellulose (pH 4.5) at 38˚C for 21 days. Subsequently, the first and second windows were covered with nail varnish after removal of the materials, and the third and fourth windows were immersed into ultrapure water at 38˚C for 28 days after being half covered with fluoride-releasing and control materials, respectively. The following procedure was performed separately during evaluations of the fluoride-releasing materials, PRG Barrier Coat ® , and FujiVII ® , using eight and six bovine teeth, respectively. The first, second, third, and fourth windows were classified into DM-PRG; Demineralized-PRG or DM-FujiVII; Demineralized-FujiVII, DM-TCM; Demineralized-traditional cement or DM-TGIC; Demineralized-traditional glass ionomer cement, RM-PRG; Remineralized-PRG or RM-FujiVII; Remineralized-FujiVII, and RM-TCM; Remineralizedtraditional cement or RM-TGIC; Remineralized-traditional glass ionomer cement, respectively. After nail varnish was removed, ∆Q values (mean ± SD) of the windows were measured using QLF-D and were compared between DM-PRG and DM-TCM, RM-PRG and RM-TCM, DM-FujiVII and DM-TGIC, and RM-FujiVII and RM-TGIC groups. ∆Q values of RM-PRG (−60 ± 44) and RM-FujiVII (−5.0 ± 10) were significantly higher than that of RM-TCM (−315 ± 193) and RM-TGIC (−56 ± 43), re-* Corresponding author. K. Watanabe et al. 128 spectively. The fluoride releasing materials provided remineralization effects to bovine enamel.

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