1. Stomatology Department; School of Medicine and Dentistry, University of Santiago de Compostela; Santiago de Compostela (A Coruña) Spain
2. Department of Preventive Medicine; School of Medicine and Dentistry, University of Santiago de Compostela; Santiago de Compostela (A Coruña) Spain
3. Department of Oral Medicine; King's College, Dental Institute; London United Kingdom
4. Galician Health Service, EOXI Lugo, Cervo e Monforte de Lemos; Lugo Spain