1. Department of Oral and Maxillofacial Surgery; George-Augusta-University; Göttingen; Germany
2. Department of Prosthodontics; George-Augusta-University; Göttingen; Germany
3. Department of Restorative Dentistry; University of Washington; Seattle; WA; USA
4. College of Dentistry; Ohio State University; Columbus; OH; USA
5. Oral and Facial Surgery Center of Puyallup; Puyallup, WA; USA