The peculiar case of inferior chemical adhesion to enamel
The mechanism and outcome of chemical adhesion onto enamel are fundamentally different from those to dentin, which can be explained by the differences in the structure and deposition of the mineral content. Functional monomers show a lower chemical reactivity to enamel HAp for several reasons. In enamel, HAp crystals are larger, the degree of crystallinity is higher, and there is a parallel crystal organization (as opposed to a crisscross orientation in dentin), making calcium ions harder to reach. 00, 000 The observed variations also impact the deposition time of monomer-Ca salts.000 Nano-layering and/or stable Ca-salt formation of 00-MDP at the adhesive interface with enamel has been proven using X-ray diffraction (XRD) to be less intensive when compared to the interface formed at dentin.