Objectives This study illustrates the use of a decision analytic model (DAM) to evaluate whether fluoride varnish application (FV) increases the proportion of caries‐free children in the Chilean preschool population, at an acceptable cost. Methods Different FV interventions were compared with an oral health counselling‐only intervention. The FV interventions were tested (with and without screening) every 6 months over 2 years, in either a preschool setting or during a well‐child programme appointment in a primary care setting. A Markov model was developed to simulate the FV performance. The model was populated with data obtained from Chilean epidemiologic studies, a systematic review and a costing study. The counselling‐only intervention was compared with FV interventions to estimate the incremental cost per child. As there was uncertainty in terms of precise parameter values both probabilistic and deterministic sensitivity analyses were performed. Results Delivery of FV in a primary care setting without screening was the most effective and the least costly intervention. Compared with counselling‐only intervention, this intervention increased the prevalence of caries‐free children in the population by 3.7%, with an extra cost (in March 2015) of £3 per caries‐free child. The results were sensitive to the starting age of FV application; increasing age would reduce the cost‐effectiveness of the FV intervention. Furthermore, cost‐effectiveness improves if some equipment such as an oral hygiene kit was not used and if less costly but qualified staff applied FV rather than dentists. Conclusions This analysis allowed the comparison of the performance of FV in realistic scenarios incorporating important aspects of health and education policies. The application of FV in a primary care setting was the most cost‐effective strategy. The work demonstrated that both the methodology and results are useful for decision‐makers.

Objectives The purpose of this study was to evaluate the cost‐effectiveness of two preventive interventions aimed at increasing the proportion of caries‐free preschool children of low socioeconomic status using a decision analytic model. Methods Two scenarios were tested, one with a school milk program (SMP) and one without (non‐SMP). Fluoride varnish (FV) and a probiotic (PB) were compared to a do‐nothing alternative among children in public nurseries/schools over a 4‐year period. FV was applied biannually and a PB (Lactobacillus rhamnosus) added to milk powder prepared daily. A Markov decision tree model was utilized. Several sources of data were used to populate the model. Probabilistic and deterministic sensitivity analyses were performed, and a public provider perspective was used. Results In the SMP scenario, PB was more effective and less costly than FV and, compared with do‐nothing, increased the proportion of caries‐free children by 14.5%, with a cost of USD 12.5 per child (June 2018). PB presented an incremental cost‐effectiveness ratio (ICER) or cost per extra caries‐free child of USD 86.2. In the non‐SMP scenario, both interventions were cost‐effective. FV (compared with do‐nothing) increased the percentage of caries‐free children by 8.3% with an ICER of USD 338.3 and PB (compared with FV) increased the effect by 6.2% with an ICER of USD 1400.2. Conclusions The findings showed that PB was most effective and less costly than FV in the SMP scenario only. This type of analysis and its results provide essential information for decision‐makers to improve the oral health of preschool children.