1. Institute of Dentistry; University of Helsinki; Helsinki Finland
2. Department of Conservative Dentistry; Faculty of Dentistry; University of Chile; Santiago Chile
3. Laboratory of Periodontal Biology; Faculty of Dentistry; University of Chile; Santiago Chile
4. Department of Oral and Maxillofacial Diseases; Helsinki University Central Hospital; Helsinki Finland
5. Department of Pathology; Faculty of Dentistry; University of Chile; Santiago Chile
6. Institute of Health Policy; Management and Evaluation; University of Toronto; Toronto Canada