1. Department of Biomedical and Neuromotor Sciences Bologna University Bologna Italy
2. Section of Implant Dentistry and Oral Rehabilitation IRCCS Orthopedic Institute Galeazzi, Dental Clinic Milan Italy
3. Department of Biomedical, Surgical and Dental Sciences Università degli Studi di Milano Milan Italy
4. Department of Periodontics and Oral Medicine University of Michigan, School of Dentistry Ann Arbor Michigan USA