Objective To evaluate the implementation process, and cost-effectiveness of fluoride varnish in preventing primary caries project for children aged 3-6 years in Huangpu District.This would provide the basis for the popularization of fluoride varnish project in preschool children as a basic measure of caries prevention in community health service.

Methods From 2016 to 2017, children aged 3-6 years old from 12 kindergartens in Huangpu District were varnished by fluoride twice a year.Three-years-old children in 12 kindergartens were divided into intervention group and control group according to the baseline survey results.The intervention group was implemented according to the established norms, while the control group was implemented according to the routine requirements.Follow-up examinations were conducted after 4 interventions to monitor primary caries increment among these children.

Results Caries rate, average caries index and SiC in children aged 3, 4, 5 and 6 years were all dropped after fluorination in year of 2018.The caries rate of 5-year-old deciduous teeth decreased from 58.8% in 2015 to 45.0% in 2018.The dental caries rate in the intervention group was lower than that in the control group, and the frequency of fluoride application per capita was higher than that in the control group, showing a statistically significant difference (P < 0.05), but there was no significant difference in the rate of fluoride application and average caries index between the two groups (P > 0.05).The direct input-output ratio of the project is 1 : 5.16.

Conclusion Fluorinated caries prevention project using fluoride varnish for preschool children can effectively reduce the incidence of dental caries in deciduous teeth and has good economic benefits.The application of standard fluorine coating on preschool children′s deciduous teeth can affect caries prevention.