In the clinical part of a two-part study on the use of glass-ionomer-silver-cermet cement as a pit and siffure sealant, 100 children between the ages of 6 and 15 years who had noncarious permanent first molar teeth bilaterally received sealants. One of the teeth was sealed with Ketac-Silver and the other received a conventional fissure sealant (Delton). At the 6-month evaluation, 94 children were examind. The number of the children examined decreased to 86 at the end of 12 months. During both evaluation periods, the percentage of teeth that had completely lost the Ketac-Silver sealant was significantly higher than the same parameter in the Delton-sealed teeth. However, there were no statistically significant differences in the caries incidences between the two groups. Nevertheless, Ketac-Silver cannot be considered an alternative to bis-GMA resin fissure sealant.