Long-term Effects of Ag-containing Alloys on Mucous Tissue Present in Biopsy Samples

Abstract

The aim of this study was to investigate the long-term effects of alloys containing silver (mainly Ag-Sn alloy) on oral mucous tissue. We observed biopsy tissue specimens from patients diagnosed as having amalgam tattoo and/or metal pigmentation by light and electron microscopy and electron-probe microanalysis (EPMA). In most cases, Ag-Sn alloy was present in the tissue but it could not be confirmed if the alloy originated from amalgam. Distributions of both Ag-S and Ag-Sn have typical patterns. Most Ag forms Ag2S and is stably deposited in three patterns along the collagen, basement membrane, and fibrous cells without inducing any host reaction. On the other hand, Sn forms large granules that contain Ag, S, C, N, P, and Ca, and is in soft state in the tissue. Tissue reactions to the alloy become weaker as time passes.

Long-term Effect of Silver Powder in vivo

“…In the case of argyria, White et al 13) demonstrated the presence of silver with S and Se in the base membrane and elastic fibers. Aoyagi and Katagiri 17) also reported the existence of silver and S in connective tissue without host reaction. Based on these reports, Ag could have bonded to the host substance through the connection of S. If so, the effect of Ag + would be reduced.…”

“…8). Aoyagi and Katagiri 17) examined Ag and S with collagen using polarized light microscopy. However, in our experiment, collagen with silver did not show any polarization.…”

“…In the present study, we focused on two characteristics of silver -the cytotoxicity of silver in culture medium and its harmless presence in the body tissues apart from pigmentation, as in the case of argyria. From a previous study on tattoos 17) , Ag and S were found in various types of body tissues in varying amounts (size) 18,19) . Leveraging on these results, we sought to further examine the host reaction to silver in terms of long-term effect arising from size difference and sulfuration to clarify the contradictions in the cytotoxicity property of silver.…”

“…Moreover, with advances in nanotechnology, nanosilver 14,15) is applied for the preparation of many consumer goods, such as sanitization agents and deodorizers. In the cases of argyria 16) (pigmentation caused by silver ingestion) and tattoos (pigmented lesions caused by amalgam), silver remains in the body for an extended period, but causes no harm to the body tissues except for pigmentation 17) . In the present study, we focused on two characteristics of silver -the cytotoxicity of silver in culture medium and its harmless presence in the body tissues apart from pigmentation, as in the case of argyria.…”

Metallic Pigmentation of Human Teeth and Gingiva: Morphological and Immunological Aspects

“…This state of delayed hypersensitivity could influence the overall immunological reactivity of the affected patients, thereby predisposing them to the development of immunologically mediated diseases, e.g., autoimmune diseases 16) . Pertaining to local tissue reactions and the longterm adverse effects, amalgam tattoos have been the subject of several studies [17][18][19][20] . On the other hand, similar studies concerning pigmentation around dental casting alloys are scarce.…”