Comparative Study on Microstructure and Mechanical Properties of Four Different Types of Amalgam

Amalgam is one of the most commonly used dental restorative material; however, because of its mercury content, risks of mercury release and its low resistance to corrosion, its clinical use is still a matter of debate among researchers. In this research four different commercially available amalgam products in Iran were studied and their mechanical, microstructural and corrosion resistance were studied and compared. In this study, four different samples of commercially available amalgam (Cinalux, Owzan Company, Iran; Honghai Tech., China; ARDENT Amalgam, Sweden; and SDI [GS-80], Australia) were prepared and mixed with mercury in an amalgamator. Then a hardened sample, measuring 6 mm in diameter and height, from each brand was evaluated by scanning electron microscopy (SEM) for ultrastructural characteristics. In addition, 3 samples from each brand undewent a compressive test in a one-axis compression test device. Resistance to corrosion of 3 samples from each brand was tested by polarization method in saline solution. To exactly compare the quantitative data, one-way ANOVA was performed using Graph Pad Prism 6 software program (α = 0.05). The results showed that although none of the samples had Gama-2 harmful phase, because of differences in the morphology of phases, they exhibited differences in corrosion resistance in the saline solution. Furthermore, their mechanical properties were different due to differences in the morphology of phases and all of them had brittle behavior and their compression strength was >300 MPa. According to the results, the microstructure of amalgam significantly affects its mechanical properties and corrosion resistance. In addition, all the samples evaluated in the present study formed identical phases.