In Vitro Effects of Three Fluoride-Free Pastes on Remineralization of Initial Enamel Carious Lesions

Purpose: The purpose of this study was to compare the efficacy of nanohydroxyapatite (NHA), casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), and calcium sodium phosphosilicate (NovaMin®) in remineralization of early enamel lesions and compare enamel surface changes using a scanning electron microscope (SEM). Methods: Thirty human premolars were sectioned into halves and randomly assigned to five groups (control, demineralization, NHA, CPP-ACP, NovaMin®; n equals 12). Ten samples in each of the three test groups were demineralized and treated with their designated paste for two minutes in 24-hour intervals for 30 days. They were subjected to the Vickers microhardness test on days 15 and 30, and their microhardness values were compared to the control and demineralization groups. The remaining two samples of each group were observed through SEM. Analysis of variance, Tukey's test, and paired t-tests were applied at P<0.05. Results: On day 15, a significant increase in surface microhardness compared to the control was only observed in the CPP-ACP group (P<0.05). Microhardness scores of all paste groups significantly increased between days 15 and 30 (P<0.001), while no significant differences were observed between them on day 30. In SEM images of all test groups, surface integrity increased, although NHA-treated samples had the most homogenous surface. Conclusion: Since all three pastes significantly remineralized incipient enamel lesions, they are potentially qualified for caries prevention.