Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX)
The enamel specimens were examined by EDX (Model 550i, IXRF Systems, TX, USA) using accelerating voltage of 15 kV, at baseline and after treatment/erosive cycles. The Ca/P ratio (wt.%) was determined at 500× magnification with SEM (SU1510, Hitachi, Ibaraki, Japan) unit by scanning 3 randomly identified areas on the surface of interest. The mean Ca/P ratio for each specimen was then calculated for further statistical analysis.The treated specimens (post-erosive cycle) were then imaged using SEM (Hitachi SU1510, Japan) at three random areas on the exposed enamel surface at 500× magnification. For the purpose of imaging, the specimens were first sputtered with platinum (80%)–palladium (20%) and then examined for surface topography. For baseline qualitative assessment, sound enamel specimens (