[Erosions of hard tooth substance]

Lemon juice was applied to intact and eroded tooth surfaces in vivo to demonstrate the development of erosions based on morphological changes. Under the influence of the fruit acid the protecting pellicles are removed and the enamel demonstrates the typical etch lesion with a honeycomb surface structure. In the dentin the acid works mainly on the peritubular area. Abrasive brushing techniques wear down the already damaged tooth surfaces.