Purpose: To compare the efficacy of different materials used as dental sealants by evaluating marginal microleakage and penetration capacity in pits and fissures.

Methods: Forty-five healthy premolars extracted for orthodontic reasons and meeting inclusion criteria were used. Teeth were cleaned, stored in saline solution up to 30 days, and randomly assigned to three groups: Clinpro, Ketac Molar Easymix, and Vitremer (3M ESPE). The materials were applied, and the samples underwent thermal cycling (5°C, 37°C, 55°C) in a distilled water solution. The apices were sealed with resin, surfaces coated with varnish, and samples immersed in 1% methylene blue stain for 24 hours. The teeth were sectioned buccolingually, and dye penetration was evaluated under a 40x stereoscopic microscope using Williams and Winters criteria.

Results: clinpro demonstrated superior performance, with 60% of samples scoring category 2 and 33.3% in category 4. Vitremer showed intermediate performance, with 33.3% in category 2. Ketac Molar Easymix had the lowest penetration, with 93.3% of samples scoring 1 or 2.