Remineralizing effects of fluoride varnishes containing nanohydroxyapatite or casein phosphopeptide-amorphous calcium phosphate

Objective: This study compared the effects of sodium fluoride varnish (NaF), NaF varnish containing nanohydroxyapatite (nano-HA), and NaF varnish containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on demineralized enamel.Methods: Thirty premolars were split mesiodistally, resulting in 60 specimens. The crowns were immersed in a demineralizing solution (pH 4.4) for 96 hours to create incipient carious lesions, then randomly assigned to three groups (n = 20): Group 1: NaF varnish, Group 2: NaF varnish containing 10 wt% nano-HA, and Group 3: NaF varnish containing 10 wt% CPP-ACP. The mineral content of enamel was evaluated by measuring the calcium-to-phosphorus ratio (Ca/P) at baseline (T1), after demineralization (T2), and following remineralization (T3) using energy-dispersive X-ray spectroscopy, and the changes in mineral content between T2 and T3 (mineral absorption) were calculated. Data were analyzed with repeated measures and one-way ANOVA, followed by Bonferroni and Tukey tests (α = 0.05).Results: ANOVA revealed no significant differences in Ca/P ratio at T1 (P=0.91) or T2 (P=0.88) among groups, but a significant between-group difference was observed at T3 (P<0.001). The nano-HA-containing NaF group had a significantly higher Ca/P ratio than other groups at T3 (P<0.05). There was a significant difference in the percentage of mineral absorption among groups (P<0.001). Group 1 had the lowest and group 2 showed the highest percentage of mineral absorption, with significant differences observed among all groups (P<0.05).Conclusions: NaF varnish containing nano-HA was significantly more effective than other groups in improving the mineral content of demineralized enamel.