Dental caries is a chronic, multifactorial bacterial infection that results in deterioration of teeth. It is the most widespread disease of civilization which affects 90% of the population. The aim of this study was to determine the difference in the oral health of children who are involved in preventive dental programs and children who are not included in the prevention program, and to perform cost-benefit analysis of the fissure sealant procedure. The study included 220 children aged 3-6 years and 150 children aged 7-14 years from a private dental practice which conducts prevention programs and 220 children from nursery schools and 150 primary school children of the same age as the control group. Clinical examination included the evaluation of caries status by the standards of the World Health Organization and calculation of DMFT index. The mean DMFT index for children 3-6 years was 2.21, while in the control group was 6.08. Mean DMFT index for children 7-14 years was 1.86, while in the control group was 4.81. Caries prevention cost-benefit analysis shows that sealing of a deciduous tooth saved 63 HRK per tooth in its simplest and most common case of filling (for a period of 7 years). The prevalence of dental caries and DMFT index were significantly lower in the children involved in the prevention program. Investments in prevention treatment are more cost effective than cost of treatment of caries on teeth that were untreated.