[1] China Med Univ, Sch Stomatol, Dept Prosthodont, Shenyang 110001, Peoples R China
[2] Northeastern Univ, Educ Minist China, Key Lab Anisotropy & Texture Mat, Shenyang 110819, Peoples R China
[3] Jiamusi Univ, Jiamusi 154007, Peoples R China
[4] Qingdao Univ, Coll Med, Affiliated Hosp, Dept Prosthodont, Qingdao 266003, Peoples R China