1. Laboratory of Periodontal Biology; Department of Conservative Dentistry; Faculty of Dentistry; University of Chile; Santiago Chile
2. Department of Conservative Dentistry; Faculty of Dentistry; University of Chile; Santiago Chile
3. Department of Pathology and Oral Medicine; Faculty of Dentistry; University of Chile; Santiago Chile
4. Leuven Biostatistics and Statistical Bioinformatics Centre; KU Leuven; Leuven Belgium
5. Department of Methodology and Statistics; CAPHRI; Maastricht University; Maastricht The Netherlands
6. Departments of Oral and Maxillofacial Diseases; Helsinki University and Helsinki University Central Hospital; Helsinki Finland
7. Division of Periodontology; Department of Dental Medicine; Karolinska Institutet; Huddinge Sweden