Resumo OBJECTIVES: We compared the incremental cost-effectiveness of 2 primary molar sealant strategies-always seal and never seal-with standard care for Medicaid-enrolled children. METHODS: We used Iowa Medicaid claims data (2008-2011), developed a tooth-level Markov model for 10 000 teeth, and compared costs, treatment avoided, and incremental cost per treatment avoided for the 2 sealant strategies with standard care. RESULTS: In 10 000 simulated teeth, standard care cost $214 510, always seal cost $232 141, and never seal cost $186 010. Relative to standard care, always seal reduced the number of restorations to 340 from 2389, whereas never seal increased restorations to 2853. Compared with standard care, always seal cost $8.12 per restoration avoided (95% confidence interval [CI] = $4.10, $12.26; P = .001). Compared with never seal, standard care cost $65.62 per restoration avoided (95% CI = $52.99, $78.26; P = .001). CONCLUSIONS: Relative to standard care, always sealing primary molars is more costly but reduces subsequent dental treatment. Never sealing costs less but leads to more treatment. State Medicaid programs that do not currently reimburse dentists for primary molar sealants should consider reimbursement for primary molar sealant procedures as a population-based strategy to prevent tooth decay and reduce later treatment needs in vulnerable young children.