This study evaluates the caries-preventive potential in permanent teeth of dental sealants when combined with an ongoing, school-based fluoride program. The investigation was designed as a sequential, cross-sectional comparison. Dental caries findings in 1987 for 416 children ages 7-11 and 14-17 who received dental sealants and fluorides were compared with corresponding data derived from 1983 baseline examinations of children who received fluoride therapy only. In addition, sealant retention status was determined. Overall mean DMFS scores in 1987 for children in two age groups combined were 51% lower than in 1983. Also, a surface-specific treatment effect was demonstrated in pit and fissures for both older and younger age groups. The overall proportion of sealants retained on occlusal surfaces of first molars after an average of 2 yr (92%) compared favorably with similar figures cited in the scientific literature. The results of this study suggest that pit and fissure sealants confer additional caries-preventive benefits beyond those of fluoride therapy alone.