[1] Nihon Univ, Sch Dent, Dept Periodontol, 1-8-13 Kanda Surugadai,Chiyoda Ku, Tokyo 1018310, Japan
[2] Nihon Univ, Grad Sch Dent, Div Appl Oral Sci, Tokyo 1018310, Japan
[3] Nihon Univ, Dent Res Ctr, Sch Dent, Tokyo 1018310, Japan
[4] Univ Texas Hlth Sci Ctr Houston, Dept Periodont & Dent Hyg, Sch Dent, 7500 Cambridge St, Houston, TX 77054 USA
[5] King Georges Med Univ, Fac Dent Sci, Dept Oral Med & Radiol, Chowk 226003, India
[6] Nihon Univ, Sch Dent, Dept Oral & Maxillofacial Radiol, Tokyo 1018310, Japan