[1] Univ Sao Paulo, Bauru Sch Dent, Dept Prosthodont & Periodont, Bauru, SP, Brazil
[2] Univ Oslo, Fac Dent, Dept Periodontol, Oslo, Norway
[3] Pavlov Univ, Dept Oral & Maxillofacial Surg, St Petersburg, Russia
[4] Univ Complutense, Fac Odontol, ETEP Res Grp, Madrid, Spain
[5] Univ Oslo, Fac Dent, Dept Periodontol, Geitmyrsveien 69, N-0455 Oslo, Norway