Introduction. Mechanical isolation of caries-free tooth fissures and anatomical pits from the oral cavity environment with the use of fissure sealants plays a particular role in reducing caries on the masticatory surfaces of permanent lateral teeth.

Aim. The study aimed to determine the expected prophylactic effect of sealing in permanent lateral teeth in 12-year old children.

Material and method. The study covered 475 children, pupils of the primary schools at the city of Lublin. The schools were selected randomly. It was assumed that the expected prophylactic effect of the sealing procedure was equivalent to complete or partial retention of the fissure sealant, the absence of a caries focus or a filling on the chewing surface of a tooth, and marginal discoloration.

Results. The sealant was most frequently present in the fissures of permanent first molars, and the number of sealed teeth in the mandible and maxilla was similar. Sealants were found in permanent premolars less frequently, while their presence was most frequent in first premolars of the maxilla. Sealants were least frequently found in permanent second molars.

Conclusions. The presence of fissure sealants in permanent lateral teeth with the expected prophylactic effect found in 12-year old Lublin children was lower than assumed. The study found 16% presence of a sealant with the expected prophylactic effect in permanent first molar teeth, which may suggest that, for various reasons, a lower than expected proportion of teeth was covered with this form of prophylaxis and the conditions for perfect performance of the procedure were not fulfilled. Nevertheless, the planned, free of charge sealing of sixth teeth resulted in the greatest number of teeth with the expected prophylactic effect in comparison to other lateral teeth