HYDROGEN PEROXIDE BLEACHING: effect of various concentrations on mercury and other metal ions release from admixed and spherical dental amalgam

Abstract

OBJECTIVE: The aim of this study was to determine the effect of different hydrogen peroxide concentrations (HP) on mercury and other metal ions release from admixed and spherical dental amalgam. MATERIALS AND METHODS: Dental amalgam discs were prepared from GS.80 and Lojic+ alloys (Southern Dental Industries, Australia) according to manufacturer’s instructions in stainless steel moulds (10mm diameter and 2mm thickness). The discs (n=25 of each alloy) were divided into five equal groups for each alloy. Each group was immersed in 20 ml of 38%, 24%, 10%, or 3% HP solution for 24 h at 37oC with 0% (distilled water) as control. Following immersion procedure, solutions were taken for metal ion release determination (Hg, Ag, Sn and Cu) using inductively coupled plasma mass spectrometry (ICP-MS). Statistical analysis was conducted using one and two way ANOVA tests to determine significance of differences between test groups. Bonferroni Post Hoc test was conducted for multiple comparisons. RESULTS: Metal ion release for the elements (Hg, Ag, Sn and Cu) increased with exposure to increasing concentrations of HP for both GS.80 and Lojic+ amalgam alloys. The differences in concentration of metal ions released after treatment with 0% (control), 3%, 10%, 24% or 38% HP were statistically significant (p < 0.05). CONCLUSION: Metal ions (Hg, Ag, Cu and Sn) were released from dental amalgam following treatment with all HP concentrations. Metal ion release increased with increasing HP concentration. Even with exposure of dental amalgam to relatively high HP concentration (38%), released Hg did not exceed the maximum acceptable limit.