Cost-effectiveness of 6-year school-based caries preventive interventions in Thailand: a system dynamics modeling study.

OBJECTIVE

This study evaluated the cost-effectiveness of 6-year school-based caries preventive interventions [supervised toothbrushing (STB) and dental sealant] in Thailand using a System Dynamics Model (SDM).

METHODS

An SDM, which simulates changes in population health over time using stocks, flows, and feedback relationships, was developed to represent caries progression. In total, three scenarios were analyzed: STB, sealant, and a base case without intervention for 6 years, covering children aged 6-12 years. Costs included interventions and treatment (fillings, endodontic treatment, and extraction). Effectiveness was measured as the number of caries-free children. Model inputs were derived from national data, literature, and expert validation. Changes in outcomes and costs were driven by intervention effects.

RESULTS

Sealant had a lower cost-effectiveness ratio (CER) of 505.3 Thai baht (15.79 USD) per caries-free child versus 537.2 baht (16.79 USD) for STB. Both were more costly and more effective than the base case, with an incremental effectiveness ratio (ICER) of 1,985.3 baht (62.04 USD) for STB and 1,210.5 baht (37.83 USD) for sealant per additional caries-free child. Sealant was dominant over STB (negative ICER), meaning it was more effective and less costly. In best-case sensitivity scenarios, sealant was more effective but also more costly than STB, representing a trade-off, with an ICER of 121.54 baht (3.80 USD) per additional caries-free child.

CONCLUSION

Sealant is the preferred strategy or a trade-off option when resources allow for additional caries-free children, while STB can serve as a low-cost alternative. Policy should prioritize sealant by optimizing effectiveness, controlling costs, and targeting high-risk groups.