The mechanisms of adhesion of the composites or resins to the tooth basically involve a system of micromechanical retentions. In the enamel, the demineralization caused by 35% phosphoric acid gives rise to microporosities that are penetrated by the adhesive, forming the so-called “microtags”. In dentin, the structure is also demineralized by phosphoric acid to a depth varying between 4 and 11 microns, exposing a network of collagen fibers that is penetrated by the adhesive. This creates a micromechanical bond between the adhesive and the dentin. There are currently three types of adhesion systems: the multicomponent system that involves acid followed by a primer and finally, the adhesive; the monocomponent system that uses the acid followed by the adhesion system; and, finally, the self-etching systems in which everything is included in a single container (17)(18)(19).