Journal of Oral Tissue Engineering

Study of the Mutagenicity of Prototype Ag-In, Porcelain Bonding and Au-Ag-Pd Alloys Containing Indium using the Umu-test

Koichi IMAI1, Tetsunari NISHIKAWA2, Tomoharu OKAMURA2, Akio TANAKA2, Tatsuro MIYAKE3, Isao TAMURA4, Hiroki ISHIKAWA5, Tomio ISEKI5, Shosuke MORITA5, Hirofumi SAWAI6, Tadashi OHKUBO6, Muneyasu SHIDA7 and Kazuhiko SUESE8
1Department of Biomaterials, 2Department of Oral Pathology,
3Department of Preventive and Community Dentistry,
4Department of Oral Anatomy, 5First Department of Oral and Maxillofacial Surgery,
6Department of Internal Medicine, 7Department of Endodontics,
8Department of Esthetic Dentistry, Osaka Dental University, Osaka, Japan

J Oral Tissue Engin 2015;13(1):27-33

The carcinogenicity of indium and its compounds is of concern, and so the Ministry of Health, Labour and Welfare specified these as chemicals which may be carcinogenic to humans by ministerial ordinance. Many carcinogens act on DNA and cause mutation, leading to cancerization. Accordingly, mutagenicity is closely involved in carcinogenicity. We extracted each component from alloy powders of prototype indium-containing silver alloy, alloy for porcelain bonding, and gold-silver-palladium alloy, and investigated their mutagenicity using the umu-test, which is a mutagenicity screening method. This test method utilizes expression of the SOS genes which repair injured DNA in bacteria, and the mutagenicity of many chemicals can be detected, similarly to the Ames test. A positive reaction was de-tected in the prototype Ag-indium alloy, but the alloy for porcelain bonding and gold-silver-palladium alloy were negative. It was clarified that close investigation of metal indium and commercial indium alloys is necessary.

Key words: Mutagenicity, Indium alloy, Ag-In, Au-Ag-Pd, Umu-test

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