Abstract: By using tapping mode atomic force microscopy(TMAFM), a polymer layer was found on the enamel surface after the exposure to xanthan gum solutions.The layer thickness is closely related to the exposure time and the concentration of xanthan gum solution.The thickness data were evaluated by a Kruskal-Wallis test and Box-Whisker Plot at a 95% confidence level(p＜0.05), and a statistically significant difference among the thickness data groups was demonstrated.After the exposure to 1000, 400, 100 mg/L xanthan gum solutions, the mean of layer thickness at the adsorption equilibrium is in the ranges of 103.5_122.06,82.4_88.94 and 45.27_55.55 nm, respectively.This phenomenon suggests that the viscosity modifying agents in the beverage might be adsorbed on the enamel surface during consumption, which may form a barrier that can protect the enamel from being attacked by acid and therefore reduce dental erosion.

Key words: Atomic force microscopy(AFM), Vertical distance, Xanthan gum, Enamel