[Etching pattern of drop-viscosity and pluggable glass-polyalkenoate lining cements under the scanning electron microscope].

The surfaces of six fast-setting glass-polyalkenoate cements of varying composition and consistency were etched with H3 PO4 for 10 and 60 seconds. Depending on the material used, the powder/liquid ratios, and the duration of acid exposure, typical etching patterns could be observed. In general the etched surfaces were characterized by the selective removal of the cement-forming matrix. Furthermore, those surfaces treated with a fine grain diamond showed a similar rough but rather irregular structure. The arithmetic mean roughness values Ra determined by an electric sectional scanning procedure ranged between 1.4 and 3.6 microns.