1. Department of Dentistry and Oral Surgery, Saku Central Hospital, Nagano, Japan
2. Department of Dentistry and Oral Surgery, Oodate General Hospital, Oodate, Japan
3. Division of Maxillo-Oral Disorders, Tohoku University, Sendai, Japan
4. Department of Oral and Maxillofacial Surgery, Akita University School of Medicine, Akita, Japan
5. Department of Dentistry and Oral Surgery, Sendai National Hospital, Miyagi, Japan.