Surface roughness and porosity of dental amalgam

The surface roughness of seven different products of dental amalgam was determined and the contribution of their porosity content and alloy particle size to that surface property was assessed. A significant correlation between roughness and porosity was found. In all amalgams the small voids were the most frequent. It was also found that the amalgam products which exhibited the highest frequency of big voids presented significantly higher surface roughness values. No significant correlation was found between roughness and alloy particle size.