Objective To evaluate the periodontal health status of residents in Lingwu and provide the basis for the development of Ningxia science and technology project benefit plan. Methods According to clinical inspection method and scoring criterion mentioned in the third national oral epidemic survey. Take the stratified ratio and random extract natural population sample 2 160 of 12,35 ~44,65 ~ 74 years old in Lingwu,The gingival bleeding,dental calculus,periodontal pocket depth three periodontal disease baseline...