1Risk and its prevention of tooth extraction in patients with hematologic diseases or digestive system diseasesDENG Tian-ge, XUE Yang, JIANG Tao, MO Jing-zhen, HU Kai-jinSYMPOSIUM449-4512Risk and its prevention of tooth extraction in patients with urinary system diseases, endocrine system diseases or metabolic diseasesLIU Chuan, HU Kai-jin, XUE Yang, LI Guo-wei, ZHOU Hong-zhiSYMPOSIUM452-4553Risk and its prevention of tooth extraction in patients with circulatory diseasesMA Yang, XUE Yang, HU Kai-jin, ZHANG Shu-yin, HOU RuiSYMPOSIUM456-4594Risk and its prevention of tooth extraction in patients with respiratory system diseases or immune system diseasesZHANG Yu, HU Kai-jin, JIANG Tao, LIU Ping, XUE YangSYMPOSIUM460-4635Effect of TiN coating on cyclic fatigue fracture resistance of Nickel-Titanium files: an in vitro studyZHANG Xue, ZHANG Xi-gang, CHEN Liang, LIU Dan, YU Jing-taoORIGINAL CONTRIBUTIONS464-467,4736Clinical evaluation of aesthetic anterior restoration with ultra-thin ceramic veneersZHANG Lei, QIAN Dong-dong, LUO Xiao-pingORIGINAL CONTRIBUTIONS468-4737Study on the effect of grafted tissue-engineered human oral mucosa on the wound healing in nude miceYU Li-jiang, SHAO Xiao-lin, LONG Xiao, WANG Xiao-jun, ZHANG TaoORIGINAL CONTRIBUTIONS474-4778Study on the effect of System B working time and times on the temperature of premolar root surfaceQIAN Ya-jie, LI Jing-jing, GAO Ya-fan, YANG Wei-dongORIGINAL CONTRIBUTIONS478-4819Effect of various modes of ultrasound on the fracture resistance of teethHAN Xue, ZHAN Fu-liang, SHAO Li-na, LIU Xin-yangORIGINAL CONTRIBUTIONS482-485,49010Analysis of complications and related factors in maxillary sinus floor elevationWANG Guang-lei, LEI LangORIGINAL CONTRIBUTIONS486-49011A sampling survey of permanent teeth caries in 12-15-year-old population in Liaoning Province (2015-2016)ZHANG Kai-qiang, CHENG Rui-bo, LI Jian, LU Zhen-fuEPIDEMIOLOGICAL SURVEY OF ORAL HEALTH491-49412Relationship between lip position response and incisor retractionYU Fei, FANG BingREVIEW495-49713Clinical application and research status of removable partial dentureHU Dan-dan, WU LinREVIEW498-50314Research progress of abnormal adhesion of the maxillary labial frenum and its therapiesZOU Yu-chun, XU Lin-yu, ZHONG QuanREVIEW504-508 