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

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

doi:10.1016/j.dental.2005.10.006

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Volume 22, Issue 10 , Pages 948-953, October 2006

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

S.K. Al-Salehi
- Centre for Biomaterials & Tissue Engineering, Department of Adult Dental Care, School of Clinical Dentistry, University of Sheffield, UK
- Corresponding author at: School of Clinical Dentistry, University of Sheffield, Claremont Crescent, Sheffield, S10 2TA, UK. Tel.: +44 114 271 7931; fax: +44 114 266 5326.
P.V. Hatton
- Centre for Biomaterials & Tissue Engineering, Department of Adult Dental Care, School of Clinical Dentistry, University of Sheffield, UK
C.A. Miller
- Centre for Biomaterials & Tissue Engineering, Department of Adult Dental Care, School of Clinical Dentistry, University of Sheffield, UK
C. Mcleod
- Department of Chemistry, University of Sheffield, UK
A. Joiner
- Unilever Oral Care, Quarry Road East, Bebington, Wirral, CH63 3JW, UK

Received 29 April 2005; received in revised form 18 October 2005; accepted 26 October 2005.

Abstract

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 24h. Discs were carefully wiped with cotton wool before immersion in distilled water (20ml) for 24h 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)μgcm⁻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.

Keywords: Tooth bleaching, Carbamide peroxide, Dental amalgam, Ion release, Surface roughness, Scanning electron microscopy