1. Maxillofacial Surgery Department, Hospital Universitario Ruber Juan Bravo, 28006 Madrid, Spain
2. Maxillofacial Surgery Department, Hospital General Universitario Gregorio Marañón, 28007 Madrid, Spain
3. Surgery Department, Universidad Complutense de Madrid, 28040 Madrid, Spain
4. Department of Public Health and Maternal and Child Health, Faculty of Medicine, Universidad Complutense de Madrid, 28040 Madrid, Spain