The corrosion resistance of post metal alloys covered by two cements

Abstract

The objective of this study was to evaluate the corrosion resistance of four types of dental alloys: Au-Pd, Ag-Pd, Ni-Cr and Cu-Al alloys covered by two different dental cements using immersion test in acidic solution. The alloys were cast into ten disc-shaped specimens (5.0 mm diameter and 0.8 mm thick). Each alloy was divided into two groups of five according to the types of cement. Each specimen was covered on one side individually by zinc phosphate cement (Zinc Cement Improved) or resin cement (Panavia F 2.0) with 0.70 mm thick. The specimens were immersed in 10 ml lactic acid/NaCl solution (pH = 2.25) and maintained in incubator at 37 °C for 7 days. The solution without specimens was used as a negative control. The released elements from each alloy into the solution were measured using inductively coupled plasma optical emission spectroscopy (ICP-OES). The elements released after 7 days immersion were reported in µg/ cm². The results found that the elements released from Au-Pd were not detected. Mean of the total elemental release of Au-Pd, Ag-Pd, Ni-Cr and Cu-Al alloys covered with Zinc Cement Improved was 4.19±2.30, 2.31±1.14 and 185.50±17.83 µ g/ cm², respectively. Au-Pd, Ag-Pd, Ni-Cr and Cu-Al alloys covered with Panavia F 2.0 was 3.69±1.51, 2.13±0.60 and 247.31±90.63 µg/cm2, respectively. Two-way ANOVA and Tamhane multiple comparisons analysis revealed the total elemental release of Cu-Al alloy was significantly higher than other alloys when covered with Zinc Cement Improved and Panavia F 2.0 (p<0.05). No significant differences were found among each alloy when cemented with Zinc Cement Improved and Panavia F 2.0 (p>0.05). The amount of elemental release was associated with corrosion resistance that was affected by types of dental alloys but not by the two types of tested cement.