Cost-effectiveness of Topical Fluoride in Preventing Deciduous Dental Caries in Preschool Children

Kindergartens Inclusion Criteria: * Kindergartens which are all located in Harbin, Heilongjiang Province, China; * Kindergartens which are basically the same in terms of school scale, student source structure, economic level and sanitary conditions; * Kindergartens with the same source of domestic water, or with the same fluoride concentration in water , and the fluoride concentration in water less than 1.0mg/L. Children Inclusion Criteria: * Children aged over 3-year and under 4-year at the time of the survey; * Children in good health; * Children with a certain degree of understanding and good compliance; * Children whose parents sign the informed consent form. Exclusion Criteria: * Children who are unable to cooperate or have a strong vomiting reflex; * Children with a history of asthma or allergies; * Children with other contraindications specified in the product manual.