Protective factors for caries of a school-based oral health program in Bangkok, Thailand: a retrospective cohort study

Abstract

© 2020 The Royal Society for Public Health Objectives: The aim of the study was to assess protective factors of a school-based oral health preventive program on caries in permanent teeth in students and to identify other risk and protective factors associated with caries in this group. Study design: This is a retrospective cohort study. Methods: A total of 433 students were examined in the 1st grade and followed up until the 6th grade. Each student was annually assessed for caries as per the World Health Organization index. Binary simple and multiple logistic regressions were performed to assess risk or protective factors with a P-value ≤0.05. Results: In 1st graders, the caries prevalence in deciduous teeth was 87.2%, and the mean decayed, missing and filled teeth (dmft) index was 6.44 (±4.4); in 6th graders, the caries prevalence in permanent teeth was 51.7%, and the mean DMFT was 1.37 (±1.84). Protective factors for caries in permanent teeth were complete participation in the program, receiving fluoride varnish >4 times, and sealant applications on all first molars. Risk factors were female sex and caries prevalence in deciduous teeth. After multiple logistic regression, sealant application only remained significant, with an odds ratio (OR) of 0.19 (95% confidence interval [CI] = 0.06–0.63, P = 0.007), and for risk factor, caries prevalence in deciduous teeth only remained significant, with an OR of 5.44 (95% CI = 2.23–13.27, P < 0.001). Conclusions: There is an association between deciduous dentition caries and permanent dentition caries. Early prevention in school settings by applying fluoride varnish and dental sealants onto molars is protective and feasible. The study suggests that regular fluoride varnish and sealant applications should be extended to similar low-income area schools.