1. Department of Humanities and Social Sciences, University of Sassari, 07100 Sassari, Italy
2. Medical Management, Hygiene, Epidemiology and Hospital Infection, University Hospital of Sassari, 07100 Sassari, Italy
3. Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy
4. Department of Medicine, Surgery and Pharmacy, University of Sassari, 07100 Sassari, Italy
5. Department of Restorative, Pediatric and Preventive Dentistry, University of Bern, 3012 Bern, Switzerland