Introduction
tooth wear, erosion
EROSION, DEMINERALISATION
Erosive tooth wear is thought to be a surface phenomenon with limited sub-surface destruction. Surprisingly, there is limited indication of the depth of the impact of acid challenges on the subsurface depth of enamel, with research tending to focus on quantitative surface methodologies Erosive challenges on enamel have been demonstrated to affect the subsurface layer through demineralisation, however most research has focused on polished surfaces, which would have exposed prisms to acid challenge The only study investigating the subsurface layer on natural surfaces to the authors knowledge is an Our ability to measure surface wear on natural enamel with profilometry has improved. Digital profiles can now be registered, and mathematical techniques used precisely analyses differences between sequential scans Therefore, the aim of this present study, was to compare differences between natural and polished enamel after combined mechanical abrasion and chemical erosion. The first null hypothesis proposed that there would be no difference in observed wear in the form of surface step height between natural and polished surfaces when exposed to erosion and erosion/abrasion challenges. The second null hypothesis was that there would be no difference in the depth of the subsurface layer on natural surfaces and polished surfaces.