1. Department of Oral and Maxillofacial Surgery; Aalborg Hospital; Aarhus University Hospital; Aalborg; Denmark
2. Department of Oral and Maxillofacial Surgery and Oral Pathology; School of Dentistry; Aarhus University; Aarhus; Denmark
3. Stereology and Electron Microscopy Research Laboratory; Aarhus Hospital; Aarhus University Hospital; Aarhus; Denmark
4. Department of Biostatistics; University of Copenhagen; Copenhagen; Denmark
5. Department of Oral and Maxillofacial Surgery; Red Cross Hospital Kassel; Kassel; Germany
6. Departments of Periodontology; Schools of Dentistry; Universities of Copenhagen and Aarhus; Copenhagen; Denmark