1 Italian Association for Metals and Biocompatibility Research - A.I.R.M.E.B.; Milan-Italy. gianpaolo_guzzi@fastwebnet.it.
2 Pavia Poison Control Center and National Toxicology Information Centre, Toxicology Unit, IRCCS Maugeri Foundation and University of Pavia-Italy.
3 Department of Biomedical, Surgical and Dental Sciences, Unit of Oral Pathology and Medicine, IRCCS Galeazzi Hospital, University of Milan; Milan-Italy.