1. Unit of Periodontology and International Centre for Evidence-Based Oral Health; UCL Eastman Dental Institute; London; UK
2. Division of Periodontics; Department of Stomatology; School of Dentistry; University of São Paulo; São Paulo; Brazil
3. Department of Periodontology; Taipei Medical University; Taipei; Taiwan
4. Department of Prosthodontics; School of Dentistry; University of Heidelberg; Heidelberg; Germany