Methods Under stratified sampling, the investigation of the oral health concept and behavior were carried out using closed type questionnaire method.
方法采取分层抽样方法，分别对口腔健康观念与行为情况进行问卷调查、填写记录。
2
The main study instrument was the open and closed-ended questionnaire, and the following interview was also employed to gain some in-depth and supplementary data.