[1] Univ Bonn, Dept Periodontol Operat & Prevent Dent, Welschnonnenstr 17, D-53111 Bonn, Germany
[2] Univ Santiago de Compostela, Dept Stomatol, Santiago De Compostela, Spain
[3] Univ Med Ctr Regensburg, Dept Conservat Dent & Periodontol, Regensburg, Germany
[4] Catholic Univ Louvain, Fac Med & Dent, Brussels, Belgium
[5] Univ Birmingham, Sch Dent, Birmingham, W Midlands, England
[6] Christian Albrechts Univ Kiel, Clin Conservat Dent & Periodontol, Kiel, Germany
[7] Univ Kent, Univ Leeds, Canterbury, Kent, England
[8] Univ Complutense, Periodontol, Madrid, Spain
[9] Radboud Univ Nijmegen, Med Ctr, Nijmegen, Netherlands
[10] Univ Pisa, Dept Surg Med Mol & Crit Area Pathol, Pisa, Italy
[11] Univ Liverpool, Dept Hlth Serv Res, Liverpool, Merseyside, England
[12] Univ Liverpool, Sch Dent, Liverpool, Merseyside, England
[13] Ernst Moritz Arndt Univ Greifswald, Univ Med, Unit Periodontol, Greifswald, Germany
[14] Univ Fed Rio Grande do Sul, Dept Prevent & Social Dent, Porto Alegre, RS, Brazil
[15] Univ Greifswald, Dept Prevent & Pediat Dent, Greifswald, Germany
[16] Univ Bern, Sch Dent Med, Dept Periodontol, Bern, Switzerland
[17] Univ Campinas UNICAMP, Piracicaba Dent Sch, Piracicaba, Brazil
[18] Univ Amsterdam, Acad Ctr Dent Amsterdam, Dept Prevent Dent, Amsterdam, Netherlands
[19] Vrije Univ Amsterdam, Amsterdam, Netherlands
[20] Hogesch Inholland, Oral Hyg Sch, Amsterdam, Netherlands
[21] Lithuanian Univ Hlth Sci, Clin Dent & Oral Pathol, Kaunas, Lithuania