RESUMO
OBJECTIVES: To compare the effectiveness of the casein phosphopeptide-stabilized amorphous calcium phosphate (CPP-ACP) in the in situ remineralization of enamel exposed with two different degrees of preformed enamel lesions. METHODS: One hundred and sixty 3 × 3 × 2 mm human enamel slabs were demineralized and divided into two subgroups according to the baseline surface hardness (SH = B1≤150 and B2 >150). During each of four 10-day experimental periods, 10 participants wore intra-oral removable acrylic palatal expanders with four human enamel slabs with preformed lesions (B1 and B2): CO1 and CO2-Control: silica dentifrice without fluoride; MP1 and MP2: MI Paste; MPP1 and MPP2: MI Paste Plus; and FD1 and FD2: Fluoride dentifrice. The Knoop hardness test (50/15s Micromet 2001, Buehler) was performed after demineralization (B1 and B2) and after treatment (T1 and T2). RESULTS: SH was higher in all treatment groups, when compared with the controls, except for CO2 (Mann-Whitney Wilcoxon Test; p < 0.05). The %SH was similar between MPP2 and FD2 and between MPP2 and MP2; however, FD2 and MPP2 products were more effective in microhardness recovery. In B1, all treatment groups were similar. CONCLUSION: MPP and FD are more effective in preventing demineralization in enamel subsurface lesions.