Abstract:Abstract : OBJECTIVE To find out the fluorine content in the water and the prevalence of dental fluorosis in children in drinking water fluorosis villages in Ninghe district of Tianjin, and to evaluate the prevention effect of drinking water fluorosis in the villages in the district. METHODS Monitoring of fluoride content in drinking water for residents of 41 sick villages in Ninghe district from 2021 to 2022. At the same time, a census was conducted on the prevalence of dental fluorosis in children aged 8 to 12 years born and residing in the 41 villages of the disease area. RESULTS Water fluoride results of residential drinking water in 41 disease area villages are qualified from 2021 to 2022. In 2021 and 2022, the results of fluoride in drinking water and the prevalence of dental fluorosis among children in 13 disease areas and 18 disease areas met the national control standards, accounting for 31.7% and 43.9% . In 2021, a total of 6 638 children were examined for dental fluorosis, of whom 3 164 were diagnosed, with a 47.7% prevalence of dental fluorosis. In 2022, a total of 6 733 children were examined for dental fluorosis, of whom 2 715 were diagnosed, with a 40.3% prevalence of dental fluorosis. Com⁃ parison of the prevalence of dental fluorosis among children in villages in 2021 and 2022, with statistically significant differences(Z= 4.581, P＜0.01). In 2021 and 2022, the dental fluorosis index of the villages in the disease area was 0.91 and 0.77, both of which were extremely mildly prevalent. CONCLUSION From 2021 to 2022, after the water re-fluoridation project was carried out in Ninghe district for the villages in the drinking water fluorosis disease area, the results of water fluoride content testing in the disease area villages met the qualified standard. The prevalence of dental fluorosis in children has been significantly reduced, however, there is still a high preva⁃ lence of dental fluorosis among children, and the situation of fluorosis prevention and treatment is still rather serious.