1. Department for Prosthodontics and Biomaterials, University Hospital Münster, D-48149 Münster, Germany
2. Department of Oral and Maxillofacial Surgery, Hospital University Münster, 48149 Münster, Germany
3. Institute of Biostatistics and Clinical Research, University of Münster, Schmeddingstraße 56, D-48149 Münster, Germany
4. Department of Oral Surgery and Policlinical Ambulance, Faculty of Health, Witten/Herdecke University, Alfred-Herrhausen-Str. 45, 58448 Witten, Germany