Aim: Determine the influence of time of passive evaporation of the solvent in a universal adhesive on the hydraulic conductance and permeability of dentin in an ex vivo human model. Henceforth, 60 healthy non-occluding third molars, indicated for therapeutic extraction/removal, of informed and consented patients aged between 18 and 30 years, were used here in. First, extracted teeth were incorporated into epoxy resin blocks and then dentin disks (1mm +/- 0.1 mm thick) were prepared. Dentin was acid etched with 35% ortho-phosphoric acid for 15 seconds in order to remove the smear layer and obtain permeable dentin. Samples were then randomized and divided into 5 groups (n=12). A Single Bond Universal adhesive layer with different time of passive evaporation of the solvent was then applied: GC=10 seconds, G1=30 seconds, G2=60 seconds, G3=300 seconds and G4=50 minutes. Finally, the flow rate was measured using a diffusion chamber, a model previously proposed by Pashley et al.