Objetives: to compare the penetration capacity and the degree of microfiltration between a resinous sealant and an ionomer with and without ameloplasty, and with or without the placement of an adhesive prior to the placement of the resinous sealant. Methodology: 90 donated premolars, free of caries obtained previous indication orthodontic, later prophylaxis, were divided into six groups, in G1: ameloplasty was performed, acid etching, resinous sealant application, G2: ameloplasty, acid etching, adhesive application and sealant resinous, G3: acid etching, application of adhesive and resinous sealant, G4: application of ionomeric sealant, G5: acid etching, application of resinous sealant, G6: ameloplasty, application of ionomeric sealant. After thermocycling, the teeth were sectioned and the fragments observed under stereomicroscope and observation to the Scanning Electron Microscope. Resu...