Background <p>The incidence of dental caries among children in Dongying City is very high. In 2018, the city launched a regional policy that provided free pit and fissure sealants and school-based oral health education. This study aims to assess the five-year impact of a regional public oral health policy.</p> Methods <p>This study adopted a census sampling method to include eligible research subjects. Through oral examinations and parent questionnaires, chi-square tests, variance analysis, and trend tests were used to evaluate the effectiveness of the intervention measures for second-grade students.</p> Results <p>The survey results showed that the overall tooth decay rate decreased from 86.4% in 2018 to 84.6% in 2022, and the difference was at the borderline significance level (<i>P</i> = 0.05). Notably, the caries rate and Decayed, Missing due to caries, and Filled Teeth index (DMFT) for permanent teeth demonstrated a significant decline (<i>P</i> &lt; 0.05), whereas those for deciduous teeth showed minimal changes. Although the filling rate for dental caries increased in 2022, it remained relatively low. The key performance indicators all showed significant trends (<i>P</i> &lt; 0.05).</p> Conclusions <p>The oral health intervention measures implemented in Dongying City effectively reduced the level of permanent tooth caries among second-grade students. However, the improvement of deciduous tooth caries was not significant, and the filling rate remained low. It is necessary to strengthen the long-term oral health behavior cultivation of both families and schools, enhance the supervision of the intervention projects, and improve the treatment work in key areas to enhance the effect of caries prevention.</p>