Aim: The aim of the study is to evaluate and compare the retention and sealing ability of pit and fissure sealants (PFS) with and without pretreatment of silver diamine fluoride (SDF)/potassium iodide (KI) on human molars under a stereomicroscope. Materials and methods: A total of 23 freshly extracted primary molars were randomly assigned to two groups; group I: pretreatment with SDF/KI; group II: pretreatment with placebo (tonic solution). Both group samples were acid etched, followed by the PFS application, and subjected to thermocycling for evaluation of sealant retention. The sealing ability of the samples was evaluated using rhodamine B dye and examined under a stereomicroscope with 10× magnification. Collected data were statistically analyzed using a percentage test and a Chi-squared test with α level of 0.05. Results: The rate of retention was significantly lower in group II (p < 0.05) than in group I, while, statistically, no difference in the sealing ability was observed between the groups (p = 1.000). Conclusion: Based on these findings, pretreating the fissures with SDF/KI has enhanced retention of fissure sealant, which could be used as a pretreatment before PFS and has an additional benefit of anticariogenic properties. Clinical significance: Sealants are successful in preventing cavities, but they only remain on the tooth for a long duration if they are completely attached to the tooth surface. Microleakage at the tooth-sealant interface is thought to have a substantial impact on the longevity of sealants due to their high failure rate. Hence, SDF has been used as a cariostatic agent because it may remineralize carious dentin and increase microhardness, and secondary caries is the major cause of failure. In an effort to decrease the dark staining of SDF, it was suggested to use KI to eliminate extra metallic silver after applying SDF.