Fig. 4

The cost-effectiveness acceptability curves and incremental cost-effectiveness scatterplot results from the probabilistic sensitivity analysis. (a) The cost-effectiveness acceptability curves demonstrate the percentage of iterations of the strategy being cost-effective when a certain willingness-to-pay was given. At a willingness-to-pay of ¥214, the fluoride treatment program was a cost-effective strategy compared with no intervention in approximately 70.5% of the simulated cases. If the WTP increased to ¥480, the prevention strategy would be cost-effective in approximately 90% of the cases. (b) The incremental cost-effectiveness scatterplot demonstrates the incremental cost and effectiveness of each simulated case as a dot on the plot. Quadrant IV is the dominant quadrant where the incremental effectiveness is positive while the incremental cost is negative. Simulated cases in the dominant quadrant are always cost-effective regardless of WTP. Simulated cases in Quadrant I are positive in incremental effectiveness but positive in incremental cost, and cost-effectiveness was decided by the willingness-to-pay. A total of 24.6% of the simulated cases fell in the dominant quadrant. The remaining cases were all in Quadrant I