This study aimed to show that the polymerization contraction of dental light cured resin-based materials, when it was used as adhesives on hard substrate, produces voids at the material/substrate interface. Two liner/base systems, one glass-ionomer, one restorative composite resins and two compomers were cured using mirror-like glass slide as a compliance-free reference substrate. The adhesive surface was analyzed by atomic force microscopy, and the polymerization contraction of bulk material was tested by laser beam scanning method. Nanoperiodic structure of 3D images, section analysis and roughness characteristics (R-a and R-z)) indicated that polymerization contraction produced voids at the interface. In visible light-cured (VLC) materials, the interface porosity decreased when an irradiation pause was carried out during gelation.