Methods: Bovine enamel blocks (n=6/group) were used and 15-min treatment with 0.1% citric acid (pH 2.74) at 37°C was employed as erosion model (control). Experiment 1: Enamel samples were exposed to 0.1% citric acid or beverage with or without various Ca sources as CaCl2, fluoride as NaF and buffering agent as NaHCO3. Experiment 2: The specimens were incubated in human saliva samples at 37°C for 2 h to form pellicle and then exposed to 0.1% citric acid with or without Ca (Ca/P = 0.3). Experiment 3: The specimens were treated with 0.1% citric acid and were immersed in saliva samples at 37°C for 24 h. Erosion was assessed by relative fluorescence reduction from sound level (ΔF, %) using QLF.
Results: In the Experiment 1, all the samples except for the beverage without Ca source (ΔF = -8.2 ± 0.7%) showed significantly lesser ΔF values compared with the control (ΔF = -11.2 ± 4.5%; p<0.05; Tukey-Kramer test) indicating inhibition of erosion. In the Experiments 2 and 3, there was no significant difference in ΔF values among the groups tested.
Conclusions: In conclusion, it was suggested that Ca and fluoride can protect enamel from erosion when these components react with acidic solutions or beverages.