1. Postgraduate Program of Dentistry, Federal University of Maranhão, São Luís 65085-580, MA, Brazil
2. National Dental Research Institute Singapore, National Dental Centre Singapore, Singapore 168938, Singapore
3. Oral Health Academic Clinical Programme (ORH ACP), Duke-NUS Medical School, Singapore 169857, Singapore
4. Section for Periodontology, Department of Dentistry and Oral Health, Aarhus University, 8000 Aarhus, Denmark
5. Postgraduate Program of Public Health, Federal University of Maranhão, São Luís 65020-070, MA, Brazil