ZHANG Liyi1, ZHANG Guangyun2, CAO Kaifang3, CAO Yuhong2
1. Peking University Health Science Center, Beijing 100191, China; 2. Xijing Hospital, Air Force Military Medical University, Xi’an 710032, Shaanxi, China; 3. Stomatology Hospital, Air Force Military Medical University, Xi’an 710032, Shaanxi, China