Visualization and measurement of nanometer dimension surface features using dental impression materials and atomic force microscopy

The resolving ability of polyvinyl siloxane impression material at a submicron scale was tested in order to determine its ability to reproduce the topographical features of worn contact surfaces such as those found in the food processing industry. Three impression materials were tested against three surfaces with standardized surface features. Cryo scanning electron microscopy and atomic force microscopy were used to provide high magnification images of the surfaces and impressions of the surfaces. Dimensional information was also provided by surface profilometry techniques using a solid stylus and a laser profilometer. Although the three impression materials accurately reproduced the line spacing of the largest scale test specimen, the least viscous material gave the most satisfactory surface reproduction, although a degree of vertical relief was lost. This material has been used to monitor wear of food contact surfaces in situ. Such information enables further research into the effect of increased or altered substratum surface roughness upon microbial and organic soil retention.