Cytotoxicity of Amalgams

Department of Pediatric Dentistry, Baylor College of Dentistry, Dallas, Texas 75246.
Journal of Dental Research (Impact Factor: 4.14). 10/1988; 67(9):1221-4. DOI: 10.1177/00220345880670091401
Source: PubMed


The purpose of this study was to compare the relative cytotoxicity of amalgams and to determine whether their toxicity depends upon composition and aging time, by means of a rapid and sensitive in vitro cell culture test. Zinc-containing amalgams showed higher cytotoxicity than did any other amalgams. High-copper amalgams had the same cytotoxicity as did the low-copper amalgam. The addition of selenium did not reduce the cytotoxicity of amalgam. Moreover, excessive additions of selenium increased the cytotoxicity of amalgam compared with that of a similar selenium-free material. The cytotoxicity of amalgam was decreased with aging time, possibly due to the combined effects of surface oxidation and further amalgamation.

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    • "Clinically they resemble OLLs (see Figure 1) which are caused by hypersensitivity reactions and can only be differentiated by exclusion based on a negative patch test [30]. Toxic reactions may be more common in amalgams with a higher zinc content [31]. "
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    ABSTRACT: Human oral mucosa is subjected to many noxious stimuli. One of these substances, in those who have restorations, is dental amalgam which contains mercury. This paper focuses on the local toxic effects of amalgam and mercury from dental restorations. Components of amalgam may, in rare instances, cause local side effects or allergic reactions referred to as oral lichenoid lesions (OLLs). OLLs to amalgams are recognised as hypersensitivity reactions to low-level mercury exposure. The use of patch testing to identify those susceptible from OLL is explored, and recommendations for removing amalgam fillings, when indicated are outlined. We conclude that evidence does not show that exposure to mercury from amalgam restorations poses a serious health risk in humans, except for an exceedingly small number of hypersensitivity reactions that are discussed.
    Full-text · Article · Jul 2012 · BioMed Research International
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    • "The toxic effects of dental amalgam, specifically mercury from amalgam are the subject of several studies [1] [2]. There is mounting evidence suggesting that chronic exposure to low levels of mercury, such as that experienced with mercury amalgam fillings can result in immune dysfunction [3]. "
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    ABSTRACT: A human-human oligodendroglial cell line MO3.13 was chosen in this study to model the loss of oligodendrocytes that occurs during episodes of multiple sclerosis. The influence of mercuric chloride (HgCl(2)) upon cell viability specifically the mode of cell death, whether by an active apoptotic mechanism or passive necrosis was determined by morphological and biochemical analysis. Mitochondrial dehydrogenase activity MTT assay showed that HgCl(2) had toxic effects on MO3.13 cells at levels of (5-25 microM) with approximately 50% cell death observed at 58 microM. Death of cells was dependent on both time and concentrations of HgCl(2). Differentiated MO3.13 cells exposed to low concentrations (25 microM) of HgCl(2) exhibited features of apoptotic cell death, including cell shrinkage and chromatin condensation. High doses of HgCl(2) (>100 microM) induced death with characteristics of necrosis. Biochemical analysis showed that HgCl(2) activated the caspase family of proteases. This was measured directly by cleavage of fluorescent substrates and by immunoblotting assay of caspase substrate proteins; alpha-fodrin, lamin B and poly (ADP-ribose) polymerase (PARP). These results indicate that HgCl(2) is toxic at low concentrations for oligodendroglial cells and that the MO3.13 cell line dies in an apoptotic manner when exposed to low concentrations of HgCl(2). However, blood mercury concentrations in vivo in a normal population with amalgam restorations are lower by a factor of some 500 times than those causing toxicity in vitro suggesting a good safety margin in respect of environmental uptake.
    Full-text · Article · Mar 2003 · Biomaterials
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    • "Palladium additions in experimental amalgams alter microstructures, yield better corrosion resistance, and stabilize they { matrix phase (Marshall, al., 1982; Omar et al., 1989). One study showed that small amounts of Se eliminated the cy totoxicity of amalgam without altering properties (Sato and Kumei, 1982), while another showed that small amounts had no effect and that larger additions had detrimental effects (Kaga et al., 1988). Other Hg-containing phases have been reported to be present in small quantities during and afterthe initial setting of amalgam, such as Cu-Hg phases (Bryant, 1985;Sarkarefa/., 1991). "
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    ABSTRACT: The goal of this presentation is to describe the material as it is used clinically, explain why small quantities of Hg can be released, and suggest ideas for amalgams that do not release mercury. A set amalgam is a dynamic material that undergoes many microstructural changes during clinical use, related to both the elevated temperature and corrosion-prone environment in the mouth and mechanical forces applied to the restoration. Amalgams can be divided roughly into two groups by their copper content: low Cu (traditional) and high Cu. High-Cu amalgams generally perform better clinically, but all amalgams corrode to some extent in the mouth. Some corrosion is deemed to be a positive factor, because corrosion product deposition reduces leakage at the margins of restorations; that is, the restorations are partly self-sealing. One of the reasons cited for the improved clinical performance of high-Cu amalgams over low-Cu amalgams is that the corrosion-prone phase, gamma 2, is nearly eliminated in high-Cu amalgams. Future research should involve improvements in the clinical performance of dental amalgams, studies of the mercury release from various types of amalgams and the toxic potential of this exposure, and the development of new amalgam systems that reduce the mercury exposure. Although the longevity of modern amalgams is impressive, it is important for their stability to be increased both clinically and microstructurally. An amalgam should be developed with a stable microstructure that, once set, would not change during clinical use. Microstructural changes lead to clinical deterioration. A stable system would not corrode, and the matrix transformation gamma 1 to beta 1 would be prohibited.(ABSTRACT TRUNCATED AT 250 WORDS)
    Full-text · Article · Oct 1992 · Advances in Dental Research
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