Dental caries represents, even today, a major public health problem. The treatment of occlusal lesions without cavity in dentin can be performed with a pit and fissure sealant, thus interrupting the progression and preserving the tooth structure. The effectiveness of sealing carious lesions using Fluroshield, which is a resinous material, is already proven. However, there are options in the market for resinous sealants with lower cost, but with their properties not yet investigated. Thus, this study aimed to analyze the progression of caries lesions by means of radiography, after using resin sealants of different brands in enamel lesions of occlusal surfaces of primary molars. A split-mouth, double-blind, randomized controlled clinical trial (patient and operator) was performed. Children between 4 and 9 years of age, with carious lesions on the occlusal surface enamel of primary teeth, were included in the study. Each participant received two types of seals, one on each side of the mouth. To assess and monitor the progression of the caries lesion, initial interproximal radiography was performed, using a positioner and a children's radiographic film. Nine participants were selected for the sample, totaling 18 primary teeth that received the intervention. These were randomly selected for the Prevent Group or Fluroshield Group. After 6 months of follow-up, there was no case of complete loss of sealant. In one of the patients, one of the teeth sealed with Prevent had been extracted, so that it was not possible to monitor the retention in this case. In 22% (n=2) of the teeth in which Fluroshield sealant was applied, and in 25% (n=2) of those in which Prevent was applied, there was a partial loss of material. There was no statistical difference between the two groups regarding the risk of partial loss of material at 6 months (p=0.665). There was no radiographic progression in any of the groups. Both sealants were able to prevent the progression of caries lesions in enamel on the occlusal surface of primary molars. Ver menos