Paolo D Pigatto1, Anna Ronchi2, Gianpaolo Guzzi3. 1. Department of Biomedical, Surgical and Dental Sciences, Unit of Oral Pathology and Medicine, IRCCS Galeazzi Hospital, University of Milan, Milan, Italy. 2. Pavia Poison Control Center and National Toxicology Information Centre, Toxicology Unit, IRCCS Maugeri Foundation and University of Pavia, Pavia, Italy. 3. Italian Association for Metals and Biocompatibility Research-A.I.R.M.E.B. (Not-for-Profit Organization), Via A. Banfi, 4, 20122, Milan, Italy. gianpaolo_guzzi@fastwebnet.it.