Surface corrosion of dental ceramics in vitro

The objective of this study was to evaluate possible structural surface cha nges in different dental ceramic materials in a provocative corrosive envir onment in vitro. On the basis of compositional and microstructural differen ces, seven dental ceramic materials were selected for the test. After sinte ring and autoglazing, the surface roughness of the specimens was evaluated by confocal laser profilometry. A specially designed specimen holder made i t possible to locate the same surface area before and after contact with th e corrosive solution. The surface topography was additionally analysed usin g scanning electron microscopy. All the ceramic materials displayed evidenc e of surface structural changes on the exposed surfaces, but to varying deg rees. Traditional leucite-containing feldspathic porcelains displayed an in crease in surface roughness compared with baseline conditions when kept in 4% acetic acid at 80 degrees C for is h. Micro-crystalline and non-crystall ine ceramic materials, on the other hand, demonstrated a smoother surface o r just a minor increase in surface roughness. Whether or not the smoother p ost-corrosion appearance of certain ceramic materials is indicative of a tr ue increase in corrosion resistance or is merely the result of an uniformly progressive corrosive process will be the object of future studies. (C) 19 99 Elsevier Science Ltd. All rights reserved.