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.