1. Periodontology Unit and Department of Clinical Research, UCL Eastman Dental Institute, London, UK
2. CAPES Foundation, Ministry of Education of Brazil, Brasília, Brazil
3. Oral and Maxillofacial Department, University of Pernambuco (FOP/UPE), Recife, Brazil
4. Graduate Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan