Resumo: | The dental amalgam is a metallic alloy commonly utilized as a restorative material. In this study, Electrochemical Impedance Spectroscopy, polarisation curves and Mott-Schottky analysis were used to evaluate the physical characteristics of the passive film formed on amalgam surface; X-Ray and UV spectrophotometric analyses were also used to determine the alloy phases and possible soluble corrosion products, respectively. This study was done with Duxalloy® and Tytin® Plus samples in four different electrolytes: Phosphate Buffer Saline, Hank Solution, Artificial Saliva and NaCl 0.9%. In general, the longer the immersion time, the smaller the resistance, possibly due to film breakage; Duxalloy® presented, at the end of 168 h of immersion, a higher resistance when compared to Tytin® Plus. X-Ray analysis showed differences between the two studied brands. UV spectrophotometric analysis demonstrated a small absorption band at ~276 nm. These films kept their protective properties after 168 h of immersion
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