1. Department of Surgery, Faculty of Medicine, University of Salamanca, 37007 Salamanca, Spain
2. School of Dentistry, Catholic University of Cuenca, Cuenca 010107, Ecuador
3. Ministry of Public Health, Cuenca 010107, Ecuador
4. School of Dentistry, Hemisferios University, Quito 170527, Ecuador
5. Department of Stomatology, Faculty of Medicine and Dentistry, University of Valencia, 46010 Valencia, Spain