1. Department of Geriatrics, The Second Affiliated Hospital, Harbin Medical University, Harbin, China
2. Department of Anesthesiology (Hei Long Jiang Province Key Lab of Research on Anesthesiology and Critical Care Medicine), The Second Affiliated Hospital, Harbin Medical University, Harbin, China
3. Department of Periodontology and Oral Mucosa, The Second Affiliated Hospital, Harbin Medical University, Harbin, China
4. Department of General Practice, The Second Affiliated Hospital, Harbin Medical University, Harbin, China