1. Department of Periodontology, Centro de Investigación e Innovación Biomédica (CIIB), Faculty of Dentistry Universidad de los Andes Santiago Chile
2. Department of Obstetrics and Gynecology, Centro de Investigación e Innovación Biomédica (CIIB), Faculty of Medicine Universidad de los Andes Santiago Chile
3. Department of Periodontology, School of Dentistry Universidad de Concepción Concepción Chile
4. Department of Statistics and Epidemiology, Faculty of Dentistry Universidad de los Andes Santiago Chile
5. Department of Periodontology, School of Dentistry Universitat Internacional de Catalunya Barcelona Spain
6. Centre of Investigation and Innovation in Clinical Dentistry, Faculty of Dentistry Universidad de la Frontera Temuco Chile