1. Department of Periodontology; Department of Oral Surgery; University of Bern; Bern Switzerland
2. Faculty of Dental Medicine; University of Laval; Quebec City QC Canada
3. Department of Periodontology and Implant Dentistry; College of Dentistry; New York University; New York NY USA
4. Department of Oral Biology; The Maurice and Gabriela Goldschleger School of Dental Medicine; Tel-Aviv University; Tel-Aviv Israel