1. Department of Prosthodontics, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150086, P.R. China
2. Department of Stomatology, Dezhou People's Hospital, Dezhou, Shandong 253000, P.R. China
3. Department of Neurosurgery, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150086, P.R. China
4. Department of Stomatology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150086, P.R. China
5. Department of Cardiology, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150086, P.R. China