The Prevalence and Associated Risk Indicators of Dental Fluorosis in China: Findings from the 4th National Oral Health Survey

Objective: To explore the prevalence and associated risk indicators of dental fluorosis in the mainland of China. Methods: Data for this study was obtained from the 4th National Oral Health Survey in China, conducted from 2015 to 2016. The sample population was 12-year-old school students. Study participants were selected using a multi-stage, stratified random sample selection procedure using a sampling frame compiled from geographical distribution of China. The level of dental fluorosis was determined using the Dean index recommended by the World Health Organization (WHO). A structured questionnaire was distributed to all the subjects in schools. Participants completed a questionnaire with assistance from staff. A bivariate analysis was performed using the chi-square test. Logistic regression was performed to evaluate the association between dental fluorosis and the independent variables. Results: A total of 27,495 students were evaluated, of which 13,650 (49.6%) were male. Overall, dental fluorosis was found in 13.4% of participants; 6.3% had very mild fluorosis, 4.3% had mild fluorosis, 2.3% had moderate fluorosis, and 0.5% had severe fluorosis. The community fluorosis index was 0.28. In the final logistic regression model students from rural areas (RR:1.582, 95%CI 1.473-1.700), students whose fathers had low education (RR:1.429, 95%CI 1.230-1.661 & 1.184, 95%CI 1.026-1.365), and those students with sibling (RR:1.537, 95%CI 1.414-1.671) were more significantly associated with dental fluorosis. Conclusion: As a whole, China has a low dental fluorosis prevalence. Rural areas were the key places for the prevention of dental fluorosis. More prevention measures should be conducted on the children whose fathers were of lower education and who were not an only child. Keywords: dental fluorosis, prevalence, risk indicator, the 4th National Oral Health Survey