[1] Okayama Univ, Grad Sch Med Dent & Pharmaceut Sci, Dept Oral & Maxillofacial Radiol, 5-1 Shikata Cho,2 Chome Kita Ku, Okayama, Okayama 7008558, Japan
[2] Bayero Univ Kano, Dept Radiol, Coll Med, Aminu Kano Teaching Hosp, PMB 3472,Zaria Rd, Kano 00234, Nigeria
[3] Bayero Univ Kano, Family Dent Dept, Fac Dent, Aminu Kano Teaching Hosp, PMB 3472,Zaria Rd, Kano 00234, Nigeria
[4] Okayama Univ, Dept Dentomaxillofacial Radiol & Oral Diag, Okayama Univ Hosp, 5-1 Shikata Cho,2 Chome Kita Ku, Okayama, Okayama 7008558, Japan