The purpose of the study was to evaluate the efficacy of the program by assessing the caries prevalence DMFT (decayed, missing and filled teeth) and periodontal status CPITN (community periodontal index of treatment needs) indices. Fissure sealant retention was also assessed in vivo. Material and method: Preventive program consisted of supervised tooth brushing twice a day, tooth brushing with Duraphat paste (Colgate-Palmolive, Poland Sp. z o.o.; concentration of fluoride 5000 ppm), on 10 occasions over a year and sealant application to sound posterior teeth. For fissure sealing two different materials: Fuji VII and Helioseal F, were used by means of a split-mouth model. Altogether 87 teeth were sealed in 15 female patients age 16 to 25. A full oral examination was carried out before initiating the program and after two years of its application. Results: The preliminary examination showed a high (8.24) mean DMFT, a high (52.08%) percentage of bleeding quadrants and 22.2% calculus presence. After this 2 year preventive program no caries was detected in the fissure sealed teeth and material was present in 90.7% of those sealed with Fuji VII and 83% with Helioseal F. Bleeding and calculus presence decreased to 42.8% and 20.8% respectively. Conclusions: A combination of topical fluoridation and fissure sealing appears to be an effective method of caries prevention in people with mental retardation.