[1] Kings Coll London, Dept Endodontol, London, England
[2] Univ Klinikum Wurzburg, Dept Conservat Dent, Periodontol, Wurzburg, Germany
[3] Univ Klinikum Wurzburg, Ctr Dent Traumatol, Wurzburg, Germany
[4] Univ Ctr Dent Med Basel UZB, Dept Periodontol Endodontol & Cariol, Basel, Switzerland
[5] Katholieke Univ Leuven, Univ Hosp Leuven, Dept Oral Hlth Sci, Endodontol, Leuven, Belgium
[6] Univ Helsinki, Dept Oral & Maxillofacial Dis, Helsinki, Finland
[7] Univ Oulu, Univ Hosp, Oulu, Finland
[8] Univ Roma La Sapienza, Rome, Italy