Effect of slow-release fluoride devices and casein phosphopeptide/amorphous calcium phosphate nanocomplexes on enamel remineralization in vitro

To investigate the remineralization effect of slow-release fluoride glass devices (SFGD), casein phosphopeptide/amorphous calcium phosphate nanocomplexes (CPP-ACP) and SFGD and CPP-ACP together on enamel pH cycling in vitro. Eighty bovine enamel slabs were allocated to each of 4 groups (20/group): SFGD; CPP-ACP; SFGD + CPP-ACP; control. Baseline surface microhardness (SMH; Knoop number) was measured for all slabs which were then subjected to a pH cycling regime for 10 days, and SMH was then remeasured. The pH cycling regime involved immersion 5 times daily (each for 5 min) in demineralization solution with the slabs immersed in artificial saliva between dipping. The treatment for the enamel slabs in the SFGD group involved exposure all the time to 2 SFGD devices per group during the cycling regime. In contrast, slabs in the CPP-ACP group were exposed to CPP-ACP slurry once daily for 30 min after the last demineralization challenge of the day. The slabs in the SFGD + CPP-ACP group received both treatments as the SFGD and CPP-ACP groups. The control group received no treatment during the cycling. There was a statistically significant difference in enamel SMH change among the groups (one-way ANOVA; p < 0.0001). Enamel SMH values in the SFGD, CPP-ACP and SFGD + CPP-ACP groups were all significantly higher than in the control group (Bonferroni; p < 0.0001). There was no significant difference in enamel SMH between the SFGD and CPP-ACP groups (p > 0.05). The use of both SFGD + CPP-ACP showed a non-significant trend for improvement in enamel SMH in comparison to SFGD or CPP-ACP alone.