Objective: To verify the effectiveness of sealing with glass ionomer cement and transversal brushing in the prevention and treatment of initial caries lesions in erupting permanent molars of children aged 5-7 years. Material and Methods: Healthy teeth with ICDAS scores 1 or 2 were selected. One hundred and thirty-one children (79 teeth in the control group -75 teeth in the test group) were randomly assigned into the two experimental groups: (1) transversal brushing technique for plaque control with conventional flat bristles and fluoridated dentifrice or (2) sealing the occlusal surfaces with glass ionomer cement (Vitro Molar ® ). Follow-up was performed for 18 months and the survival analysis was applied to test the occurrence of lesion progression. Results: The mean age of children was 5.4 years and it was verified that, by examining the initial tooth condition, the probability of progression was 66% lower when the tooth had initial caries lesions than when it was healthy; the probability of molar progression was about 74% lower in the test group compared to the control group. The mean time for lesion development in the test group (16.8 months; SD = 0.5) was greater than that in the control group (16.5 months; SD = 0.5; p=0.008). Conclusion: Sealing reduces the progression of caries disease in initial lesions when compared to the transversal brushing technique.