The effect of hydrogen peroxide concentration on metal ion release from dental amalgam

Objectives The aim of this study was to investigate the effect of hydrogen peroxide (HP) concentration on metal ion release from dental amalgam. Methods Dental amalgam discs (n = 25) were prepared by packing amalgam into cylindrical plastic moulds (10 mm diameter and 2 mm height). The discs were divided into five equal groups and each group was immersed in 20 ml of either 0%, 1%, 3%, 10% or 30% HP solution for 24 h at 37 °C. Samples were taken for metal ion release determination (Hg, Ag, Sn and Cu) using inductively coupled plasma mass spectrometry (ICP-MS). The surface roughness of each disc was measured before and after bleaching. Results The differences in concentration of metal ions released after treatment with 0% (control) and each of 1%, 3%, 10% and 30% HP were statistically significant (p < 0.05). Metal ion release for the elements (Hg, Ag, Sn and Cu) increased with exposure to increasing concentrations of HP. Surface roughness measurements of the samples before and after treatments with HP solutions were not significantly different (p > 0.05). Conclusions Exposure to HP bleaching agent was associated with increased metal ion released from dental amalgams compared to treatment with a control solution. Ion release was in proportion to the peroxide concentration tested, with the highest concentration associated with the greatest metal ion release for all elements investigated.