Erosive Potential of Modified Orange Juices in Enamel and Dentin

Objectives: to evaluate the erosive potential of modified orange juices in enamel and dentin. Methods: five substances: 3.1 g/L calcium lactate pentahydrate (Ca); 0.2 g/L xanthan gum (XG), 0.2 g/L sodium hexametaphosphate (HMP); 0.2 g/L sodium pyrophosphate tetrabasic (PP), 0.2 g/L sodium tripolyphosphate (STP) and the combination of Ca and HMP (Ca+HMP) were added to a commercially available orange juice (OJ). OJ with no additives was used as negative control (C-) and a commercially available calcium-modified juice as positive control (C+). They were evaluated using an in vitro erosion-remineralization cycling model. Eighty enamel and 80 root dentin specimens (4x4mm) were ground flat and polished. Adhesive tapes were placed on, leaving an exposed area of 4x1mm. The specimens were randomly assigned to the experimental groups (n=10) and immersed in the respective solutions for 5min, 6x/day for 5 days. Between the immersions and overnight they were stored in artificial saliva. After the cycling, the enamel specimens were analyzed by surface Knoop microhardness (50g, 15s) and optical profilometry, while dentin specimens were analyzed only by profilometry. Outcomes were statistically analyzed considering a significance level of 5%. Results: For enamel, no detectable surface loss was found for C+, Ca, Ca+HMP and HMP groups. The surface loss for the groups STP, PP and XG were not significant different from C-. The group C+ presented the lowest microhardness change, followed by Ca+HMP and Ca. STP, PP, HMP and XG were similar to C-. For dentin, C+ had the lowest surface loss, followed by Ca+HMP. No difference was found between all the other groups and C-. Conclusions: For enamel, the addition of calcium, even in lower concentration was able to reduce the erosion caused by the OJ. Additional reduction was obtained when calcium was combined with HMP. For dentin, a significant reduction was found only by Ca+HMP