1 Department of Experimental Medicine, Section of Hygiene, Occupational Medicine and Forensic Medicine, Second University of Naples, Via dei Crecchi 16, Naples, 80133 Italy.
2 Department of Orthodontics, Second University of Naples, Naples, Italy.
3 Department of Mental Health and Public Medicine, Section of Infectious Diseases, Second University of Naples, Naples, Italy.
4 Institute for Health Services, Research in Dermatology and Nursing, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
5 Institution for Statutory Accident Insurance and Prevention in Healthcare and Welfare Services, Hamburg, Germany.
6 Department of Operative Dentistry, Dental School, UFMG - Universidade Federal de Minas Gerais, Belo Horizonte, MG Brazil.