1. Department of Oral and Maxillofacial Surgery School of Dentistry Health Sciences University of Hokkaido Hokkaido Japan
2. Group of Polymer and Ceramic Materials Industrial Research Institute Hokkaido Research Organization Hokkaido Japan
3. Department of Orthopedic Surgery Graduate School of Medicine Hokkaido University Sapporo Japan
4. Department of Spine and Spinal Cord Disorders National Hospital Organization Hokkaido Medical Center Sapporo Japan