Optical profilometric study of changes in surface roughness of enamel during in vitro demineralization

The application of non-contact optical profilometry for non-destructive stu dy of changes in the surface roughness of natural enamel surfaces during in vitro demineralization was investigated. Repeated measurement of profiles of the same enamel surfaces after successive demineralization episodes was achieved by a kinematic specimen mount that could be removed, then accurate ly repositioned. Surface roughness parameters and reflectivity of natural e namel surfaces exposed to either a demineralizing solution (test) or deioni zed water (control) for up to 6 days were measured at 6- to 24-hour interva ls. The results prior to demineralization showed that surface roughness var ies with position on the enamel surface. During demineralization there was an approximately linear increase in surface roughness for the first 70 h fo llowed by somewhat erratic behaviour, and a saturating exponential with tim e increase in reflectivity for the first 70 h which subsequently remained c onstant. Changes in enamel surface during in vitro demineralization were al so observed using scanning electron microscopy. Copyright (C) 2000 S. Karge r AG, Basel.