The effect of carbamide peroxide treatment on metal ion release from dental amalgam

S. K. Al-Salehi, P. V. Hatton, C. A. Miller, C. Mcleod, A. Joiner

    Research output: Contribution to journalArticlepeer-review


    Objectives: There is concern that hydrogen peroxide generated by tooth bleaching agents may cause enhanced metal ion release (including mercury) from dental amalgam following contact. The aim of this in vitro study was therefore to investigate the effect of a carbamide peroxide (CP) based tooth bleaching gel on metal ion release from dental amalgam. Methods: Dental amalgam discs were prepared according to the manufacturers' instructions. These were treated with either a 10% carbamide peroxide (CP) gel or a 0% CP gel for 24 h. Discs were carefully wiped with cotton wool before immersion in distilled water (20 ml) for 24 h at 37 °C. Following immersion, water samples were taken for metal ion release determination (Ag, Cu, Hg and Sn) using inductively coupled plasma mass spectrometry methods. The specimens were further evaluated for surface changes using scanning electron microscopy (SEM) and Talysurf surface roughness measurements. Results: The differences in concentration of metal ions released after treatment with the 10% CP gel and a placebo gel treatment were not statistically significant (p > 0.05). For example, mercury release following treatment with the 10% CP gel and the 0% CP gel was found to be 1.17(0.5) and 0.57(0.1) μg cm-2, respectively. Roughness measurements for samples treated with the 10% CP gel and 0% CP gel were 2.23(0.47) and 1.74(0.16) μm, respectively, again showing no significant difference between groups (p > 0.05). SEM images of the amalgam surfaces showed no apparent differences between treatments. Significance: Treatment with a 10% CP gel did not significantly enhance subsequent metal ion release from dental amalgams compared to a control gel, contradicting previously published studies. © 2005 Academy of Dental Materials.
    Original languageEnglish
    Pages (from-to)948-953
    Number of pages5
    JournalDental Materials
    Issue number10
    Publication statusPublished - Oct 2006


    • Carbamide peroxide
    • Dental amalgam
    • Ion release
    • Scanning electron microscopy
    • Surface roughness
    • Tooth bleaching


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