Methods: A permanent molar tooth was prepared so that 6 'windows' of sound enamel were exposed to 0.1M Acetic acid (pH4) as a demineralising solution for 6, 12, 24, 36, 48 and 72 hours. The enamel was scanned before and after demineralisation using X-ray microtomography at a resolution of 30µm.
Results: Mineral concentration decreases from the natural surface towards the EDJ. The mineral concentrations at the surface and at the EDJ are the same in all the regions, irrespective of the enamel thickness. Hence the gradient is steeper in thinner enamel than it is in thicker enamel. No erosive loss was seen in the 6 and 12 hour exposures. Erosive depth generally increased with time of exposure, but for the thinner enamel exposed for 48 hours, the depth of loss appeared to be the same as for the thicker enamel exposed for 72 hours.
Conclusions: The depth of erosive damage depends on the mineral concentration gradient of the enamel.