Aim. Assessment of the dental caries prevalence among 12-year-old children in Belarus and Russia and evaluation a possible effect of the primary prevention programs on oral health in adult population. Methods. Meta-analysis of the world dental literature and study of the descriptive epidemiology data on the prevalence of dental caries among key age groups of children, adolescents and adults using earlier study data carried in Minsk and Moscow and within the intercountry scientific project using the EGOHID system in 2013—2017 yrs. Results. Analysis of the epidemiology data on the DMFT of 12-year-old children in the last 40—50 years suggested a trend of the reduction of dental caries prevalence in Belarus and Russia by 10—15%. An effect of the long-term preventive programs on dental caries in adults and elderlies was dubious. Conclusion. The evident success in primary prevention of dental caries in children might improve oral health in adolescents and adult people, however, it had no, or minimal effects on the oral health of elderlies.