White spot lesions(WSLs), due to enamel demineralization, occur frequently in orthodontic treatment. We recently developed a novel rechargeable dental composite containing nanoparticles of amorphous calcium phosphate(NACP) with long-term calcium(Ca) and phosphate(P) ion release and caries-inhibiting capability. The objectives of this study were to develop the first NACPrechargeable orthodontic cement and investigate the effects of recharge duration and frequency on the efficacy of ion re-release.The rechargeable cement consisted of pyromellitic glycerol dimethacrylate(PMGDM) and ethoxylated bisphenol A dimethacrylate(EBPADMA). NACP was mixed into the resin at 40% by mass. Specimens were tested for orthodontic bracket shear bond strength(SBS) to enamel, Ca and P ion initial release, recharge and re-release. The new orthodontic cement exhibited an SBS similar to commercial orthodontic cement without CaP release(P40.1). Specimens after one recharge treatment(e.g., 1 min immersion in recharge solution repeating three times in one day, referred to as “1 min 3 times”) exhibited a substantial and continuous re-release of Ca and P ions for 14 days without further recharge. The ion re-release did not decrease with increasing the number of recharge/re-release cycles(P40.1). The ion re-release concentrations at 14 days versus various recharge treatments were as follows: 1 min 3 times43 min 2 times41 min 2 times46 min 1 time43 min 1 time41 min 1 time. In conclusion, although previous studies have shown that NACP nanocomposite remineralized tooth lesions and inhibited caries, the present study developed the first orthodontic cement with Ca and P ion recharge and long-term release capability. This NACP-rechargeable orthodontic cement is a promising therapy to inhibit enamel demineralization and WSLs around orthodontic brackets. We recently developed a novel rechargeable dental composite containing nanoparticles of amorphous calcium phosphate (NACP) with long-term calcium (Ca) and phosphate (P) ion release and caries-inhibiting capability. The objectives of this study were to develop the first NAC Prechargeable orthodontic cement and investigate the effects of recharge duration and frequency on the efficacy of ion re-release. The rechargeable cement consisted of pyromellitic glycerol dimethacrylate (PMGDM) and ethoxylated bisphenol A dimethacrylate (EBPADMA). NACP was mixed into the resin at 40% by mass. Specimens were tested for orthodontic bracket shear bond strength (SBS) to enamel, Ca and P ion initial release, recharge and re-release. The new orthodontic cement exhibited an SBS similar to commercial orthodontic cement without CaP release (P40.1). Specimens after one recharge treatment (eg, 1 min immersion in recha rge solution repeating three times in one day, referred to as “1 min 3 times ”) showed a substantial and continuous re-release of Ca and P ions for 14 days without further recharge. The ion re-release did not decrease with increasing the number of recharge / re-release cycles (P40.1). The ion re-release concentrations at 14 days versus various recharge treatments were as follows: 1 min 3 times43 min 2 times41 min 2 times46 min 1 time43 min 1 time41 min In conclusion, the present study developed the first orthodontic cement with Ca and P ion recharge and long-term release capability. This NACP-rechargeable orthodontic cement is a promising therapy to inhibit enamel demineralization and WSLs around orthodontic brackets.