1. Department of Materials Science and Engineering; Institute of Biomaterials; University of Erlangen-Nuremberg; 91058 Erlangen Germany
2. Department of Oral and Maxillofacial Surgery, Surgical Hospital/Helsinki University Central Hospital; PO Box 263, 000 29 HUS Helsinki Finland
3. Department of Materials Science and Engineering, Institute of Polymer Materials; University of Erlangen-Nuremberg; 91058 Erlangen Germany
4. Department of Hand and Orthopaedic Surgery; Helsinki University Central Hospital; Helsinki Finland