Affiliation: | 1.Department of Stomatology, The Second Hospital of Tangshan City, Tangshan, Hebei 063000, P.R. China;2.Department of Stomatology, North China University of Science And Technology Affiliated Hospital, Tangshan, Hebei 063000, P.R. China;3.Department of Stomatology, The Third Hospital of Shijiazhuang City, Shijiazhuang, Hebei 050011, P.R. China;4.Department of Stomatology, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, P.R. China |