1. Department of Oral and Maxillofacial Surgery – Plastic Operations University Medical Center Mainz Mainz Germany
2. School of Medicine; National Clinical Research Center for Oral Disease, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology Second Dental Clinic, Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University Shanghai China
3. Center for Epidemiology and Surveillance of Oral Diseases (CESOD), Faculty of Dentistry Universidad de Chile Santiago Chile
4. Postgraduate School, Faculty of Dentistry Universidad de Chile Santiago Chile