1. Department of Restorative, Preventive and Pediatric Dentistry, University of Bern, Freiburgstrasse 7, 3012 Bern, Switzerland
2. Department of Medicine, Surgery and Pharmacy, University of Sassari, 07100 Sassari, Italy
3. Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy
4. University Hospital of Sassari, 07100 Sassari, Italy