A study of the surface topography and roughness of glazed and unglazed feldspathic ceramics.

The aim of this study was to obtain the 3-D qualitative and quantitative nanoscale data of the surface topography and surface roughness of glazed and unglazed feldspathic ceramics. Twelve samples composed of Ni-Cr alloy (Wiron 99, Bego Germany) and feldspathic ceramics (IPS Classic, Ivoclar-Vivadent, Schaan, Liechtenstein) were prepared, and divided into two groups, dependent of the surface final finishing; 6 unglazed and 6 glazed samples. The surface of the samples was recorded and analysed by atomic force microscopy (AFM, Veeco Instruments, Santa Barbara, CA, U.S.A.). According to the results of this study, unglazed ceramic surface is significantly rougher than the glazed one, showing significantly higher root mean square (RMS), mean roughness (Ra) and maximum height (Z range values) (p < 0.01), higher crystallites with sharper peaks and deeper pores. The roughness parameters of the unglazed samples were almost twice or even more higher than of the glazed samples. Exposed unglazed ceramic surfaces can therefore promote antagonistic tooth wear.