Long-term Impact of Kindergarten Dental Outreach Service on School Students

This retrospective observational study investigated the association between kindergarten dental outreach service provided by the Faculty of Dentistry, University of Hong Kong, and dental caries experience and treatment received among primary school students using electronic data retrieved from the School Dental Care Service (SDCS) provided by the Hong Kong government. The outreach service encompassed oral examination, oral health education, and silver diamine fluoride application. Grade 3 or 4 primary school students participating in the SDCS were recruited from school dental clinics in 2022. Questionnaire surveys were administered to children and their parents. Children's clinical records since primary school entry were obtained from the SDCS. Children were classified into the exposure group if they attended kindergartens that received outreach services from 2015 to 2019; others were classified as the nonexposure group. The inverse probability weighting method was used to adjust for confounding. Among 964 children with clinical data, 180 (18.7%) were in the exposure group, and 784 (81.3%) were in the nonexposure group. From grades 1 to 3, the respective prevalences of caries experience were 54.6%, 60.7%, and 57.6% and the mean (SD) dmft scores were 2.5 (3.1), 2.4 (2.8), and 2.0 (2.4). After adjustment, the exposure group showed a lower prevalence of decayed primary teeth in grade 3 (difference, -9.8%; 95% CI, -18.0% to -1.6%; P = 0.019) and a lower mean number of decayed primary teeth in grade 2 (difference, -0.4; 95% CI, -0.7 to -0.1; P = 0.017). Children received a mean (SD) 6.6 (5.7) treatment items over 3 school years, with annual means of 2.7 (3.3), 2.0 (3.0), and 1.9 (2.2) from grades 1 to 3. No significant association was found between exposure and treatment received. In conclusion, the outreach service demonstrates a promising long-term impact in preventing caries in primary teeth among primary school children.