Trends in Dental Caries Experience Among 12-Year-Old Children in Korea, Japan, and Taiwan in Relation to Preventive Policies and Insurance Coverage

Abstract

This study compared long-term trends in the decayed, missing, and filled permanent teeth (DMFT) index among 12-year-old children in Korea, Japan, and Taiwan using national oral health survey data. It also examined these changes in relation to preventive policies, dietary environments, and healthcare systems. Mean DMFT was extracted from official national surveys and analyzed descriptively to assess temporal patterns. Major oral health policies and related contextual factors were reviewed based on government reports and previous literature. In all three countries, mean DMFT increased during the earlier study period and subsequently decreased, indicating an overall improvement in childhood oral health. However, differences were observed in the timing, rate of decline, and recent DMFT levels. Japan showed an earlier and more sustained reduction and maintained the lowest DMFT levels in recent years. Korea demonstrated a marked decline after 2000, followed by a plateau, while Taiwan showed a gradual decrease but remained at relatively higher levels. These differences may reflect differences in the implementation, coverage, and continuity of preventive programs, fluoride exposure, and dental care access. However, causal relationships cannot be inferred due to the descriptive ecological design and limitations in comparable data across countries and periods. In conclusion, although dental caries experience has declined over time among 12-year-old children in Korea, Japan, and Taiwan, differences remain. Strengthening preventive strategies with attention to accessibility and long-term implementation may be important for further reducing disparities.