[1] Shandong Univ, Jinan Cent Hosp, Dept Stomatol, Jinan, Shandong, Peoples R China
[2] Med Univ Vienna, Univ Clin Dent, Div Periodontol & Conservat Dent, Vienna, Austria
[3] PLA Strateg Support Force Characterist Med Ctr, Dept Stomatol, Beijing, Peoples R China
[4] Fujian Med Univ, Affiliated Hosp 1, Dept Oral & Maxillofacial Surg, Fuzhou, Fujian, Peoples R China