1. a Department of Biomaterials, Faculty of Dental Surgery, University of Paris Descartes, 1 rue Maurice Arnoux, F-92120 Montrouge, France
2. b Department of Biomaterials, Faculty of Dental Surgery, University of Paris Descartes, 1 rue Maurice Arnoux, F-92120 Montrouge, France;, Email: my.degrange@wanadoo.fr