Effect of treatment with phosphate, casein phosphopeptide and fluoride on the remineralization: in vitro study

This study aimed to evaluate in vitro the effect protocols and anticaries agents containing casein amorphous calcium fluoride phosphopeptide-phosphate (CPP-ACPF, MI Paste Plus), sodium trimetaphosphate (TMP) and fluoride (F), in remineralization of caries lesions. Bovine enamel blocks with initial caries lesions were divided into groups (n = 12): 1) Toothpaste without F-TMP-MI Plus (Placebo); 2) Toothpaste 1100 ppm F (1100F), 3) 1100F + MI Paste Plus (1100F-MI Paste Plus), 4) Toothpaste with 1100F + Neutral gel with 4,500 ppm F + 5%TMP (1100F + Gel TMP) and 5) Toothpaste with 1100F + Neutral gel with 9,000 ppm F (1100F + Gel F). For the 4 and 5 groups the gel was applied only once for 1 minute, initially to the study. For the 3 group, after treatment with 1100F, MI Paste Plus was applied 2x/day for 3 minute. After pH cycling, the percentage of surface hardness recovery (%SHR); integrated loss of subsurface hardness (ΔKHN); profile and depth of the subsuperficial lesion (PLM); concentrations of F, calcium (Ca) and phosphorus (P) in enamel was determined. The data were analyzed by ANOVA (1-criterion) and Student-Newman-Keuls test (p < 0.001). Treatment with 1100F alone led to ~ 28% higher remineralization when compared to treatment with 1100F associated with MI Paste Plus (p < 0.001). The 1100F and 1100F + Gel F groups showed similar values for %SHR (p = 0.150). 1100F + Gel TMP treatment also remineralized the enamel surface by ~ 30% and 20% when compared to the 1100F + Gel F and 1100F groups (p < 0.001). The lower lesion depth (AKHN) was observed for the 1100F + Gel TMP group (p < 0.001), where it was 54% and 44% lower in comparison to the 1100F and 1100F + Gel F groups (p < 0.001). Polarized light microscopy photomicrographs showed subsurface lesions in all groups, but these lesions were present to a lower extent in the 1100F + Gel TMP group (p < 0.001). Treatment with 1100F + Gel TMP promoted an increase in the concentration of Ca in the enamel by ~ 57% and ~ 26% when compared to the 1100F and 1100F + MI Paste Plus groups (p < 0.001), respectively. There were no significant differences between the 1100F, 1100F + MI Paste Plus and 1100F + Gel F groups (p > 0.001). Similar values of P in the enamel were observed in the 1100F, 1100F + MI Paste Plus and 1100F + Gel F groups (p > 0.001), except for the 1100F + Gel TMP group, which presented a high concentration (p < 0.001). We conclude that the 1100F+TMP gel treatment/protocol led to a significant increased remineralization when compared to the other treatments/protocols and may be a promising strategy for patients with early caries lesions.