[1] Univ Tsukuba Hosp, Dept Oral & Maxillofacial Surg, Tsukuba, Ibaraki, Japan
[2] Univ Tsukuba, Inst Clin Med, Fac Med, Dept Oral & Maxillofacial Surg, Tsukuba, Ibaraki, Japan
[3] Ibaraki Cent Hosp, Ibaraki Canc Ctr, Dept Oral & Maxillofacial Surg, Kasama, Ibaraki, Japan
[4] Univ Tsukuba Hosp, Ctr Med Educ & Training, Tsukuba, Ibaraki, Japan
[5] Tsurumi Univ, Sch Dent Med, Dept oral & Maxillofacial Surg, Yokohama, Kanagawa, Japan
[6] Ibaraki Cent Hosp, Ibaraki Canc Ctr, Dept Oral & Maxillofacial Surg, Kasama, Ibaraki 3091793, Japan