[1] Iwate Med Univ, Sch Dent, Dept Prosthodont, Div Fixed Prosthodont & Oral Implantol, 19-1 Uchimaru, Morioka, Iwate 0208505, Japan
[2] Iwate Med Univ, Sch Dent, Dept Reconstruct Oral & Maxillofacial Surg, Div Oral & Maxillofacial Surg, Morioka, Iwate, Japan
[3] Hokkaido Univ, Fac Dent Med, Dept Oral Diag & Med, Sapporo, Japan
[4] Hokkaido Univ, Grad Sch Dent Med, Sapporo, Japan
[5] Aichi Gakuin Univ, Sch Dent, Dept Fixed Prosthodont & Oral Implantol, Nagoya, Aichi, Japan