The sealing of fossae and fissures is an effective procedure in preventing occlusal caries lesions. However, there are gaps regarding its efficacy in the treatment of initial enamel lesions. In addition, there are no studies in the literature that have compared the longevity of sealings performed with the different sealants available in the market. Thus, the objective of this study is to evaluate the efficacy of fossae and fissures sealings performed with a low-cost resinous sealant in occlusal lesions in enamel in permanent and deciduous molars. This is a multicenter clinical study of non-inferiority, randomized, controlled, double blind (patient and operator) with 60 deciduous molars and 340 permanent molars of children 4 and 9 years of age. The sample unit will be the tooth, which will be randomized into two groups using a distributed randomization list in mixed envelopes that will be open only at the time of the procedure. The teeth allocated in the test group will be treated with the sealant preventâ; Those allocated in the control group will employ the Fluroshieldâ sealant. In both groups the procedure will follow the manufacturer's standards. The efficacy of the sealant will be evaluated by means of clinical and radiographic control at 6, 12 and 18 months after the procedure. Secondary outcomes, such as retention, cost, acceptability and quality of life, will also be evaluated.

Inclusion Criteria:

• Children with at least two deciduous and/or permanent molars with occlusal caries lesions scores 1, 2 or 3 of the Icdas (Ismail et al., 2007) will be included, one on each side, preferably from the same arch.

Exclusion Criteria:

• Patients with special needs;
• using orthodontic appliances;
• with systemic diseases;
• Teeth that present restorations, sealants, formation defects, deep caries lesions that may lead to pulp impairment;
• teeth with fistula and/or abscess;
• teeth with spontaneous painful symptomatology.