1. 1 Department of Oral and Maxillofacial Surgery, Showa University School of Dentistry, Tokyo, Japan.
2. 2 Department of Oral and Maxillofacial Surgery, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
3. 3 Dental Implant Center, Nagasaki University Hospital, Nagasaki, Japan.
4. 4 Department of Applied Prosthodontics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
5. 5 Department of Crown and Bridge Prosthodontics, Oral Functional Sciences, Graduate School of Dental Medicine, Hokkaido University, Hokkaido, Japan.
6. 6 Department of Oral and Maxillofacial Surgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.