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