Affiliation: | 1. Department of Oral Surgery, Heinrich Heine University, , Düsseldorf, Germany;2. Department of Periodontology, University of Berne, , Berne, Switzerland;3. Department of Periodontology, Kagoshima University Graduate School of Medical and Dental Sciences, , Kagoshima, Japan;4. Department of Oral Surgery and Stomatology, University of Berne, , Berne, Switzerland |