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Updated: Aug 20, 2026

A Study of the Complexation of Mercury(II) with Dicysteinyl Tetrapeptides by Electrospray Ionization Mass Spectrometry
Published on: January 8, 2016
Effect of sodium hypochlorite and EDTA on mercury released from amalgam
I Rotstein1, M Karawani, S Sahar-Helft
1Division of Surgical, Therapeutic and Bioengineering Sciences, School of Dentistry, University of Southern California, Los Angeles 90089-0641, USA. ilan@usc.edu
Objectives:
The effect of sodium hypochlorite (NaOCl) and EDTA on mercury released from dental amalgam was assessed in vitro.
Study Design:
Fifty-six samples of dental amalgam of similar size were prepared and exposed to a 10-mL solution of either 1% NaOCl, 3% NaOCl, 10% EDTA in 1% NaOCl, or 10% EDTA in 3% NaOCl for periods of 20, 40, and 60 minutes. Mercury concentrations in the solutions were measured by using a cold-vapor atomic absorption Mercury Analyzer System, and the differences between the groups were statistically analyzed.
Results:
All amalgam samples exposed to 1% NaOCl and 3% NaOCl-either alone or in combination with EDTA-released mercury into the solutions. Mercury release was significantly higher in the test groups than in the EDTA, distilled water, or phosphate buffer controls (P <.001). Increase in the mean concentration levels of mercury in solution was time-dependent and directly related to NaOCl concentration. The addition of EDTA caused a reduction in mercury levels detected in solution, which was more significant in amalgam samples exposed to 1% NaOCl combined with EDTA (P <.001).
Conclusions:
NaOCl solutions commonly used for root canal cleaning and shaping cause mercury release from dental amalgam and may alter its chemo-physical properties as a sealant for root perforations.
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