Qualitative and quantitative analysis of Mercury ions on the surface of amalgam restorations after home bleaching

Abstract

ABSTRACT Objective The bleaching agents may interact with restorative materials, such as dental amalgam, providing an increase mercury ions (Hg) release, whose toxic effect is known. Whereas many patients have amalgam restorations (AR) and seek bleaching treatments, the present study aimed to evaluate in vitro the amount of Hg released from AR made with spherical alloy, after being subjected to different concentrations of carbamide peroxide (CP) for home bleaching. Methods 40 class I AR were prepared in bovine teeth. Afterthe restoration, the samples were randomly allocated into 4 groups (n = 10): C (control group), CP10 (CP 10%) CP15 (CP 15%) CP20 (CP 20%) and its treatments were simulated for 14 days for 6 hours daily. The Hg ions released was measured by energy dispersive X-ray spectroscopy (EDS) and surface changes were assessed in the Scanning Electron Microscope (SEM). Hg levels (percent mass) were recorded and the differences were statistically analyzed using the Kruskal-Wallis test and Dunn’s “Post hoc” test. Results Statisticalanalysis showed the bleaching treatment resulted in a higher Hg release (p <0.05), although no visible changes were identified in micrographs when comparing the control group with the other groups (CP10, CP15, CP20). Conclusion Increased Hg release may be observed during simulated home bleaching.

Keywords

• Dental amalgam
• Mercury
• Tooth bleaching