Double-layer glass-ceramic coatings on Ti6Al4V for dental implants

Double-layer bioactive glass-ceramic coatings were prepared on Ti–6Al–4V substrates by dipping and firing. A SiO2–CaO–Na2O–MgO–P2O5–K2O (SCP) based glass was used as first layer in direct contact with the metallic substrate and a SiO2–Al2O3–P2O5–K2O–CaO–F− (SAF) based glass-ceramic was used as outer bioactive layer. The deposition of the intermediate SCP layer was necessary in order to obtain a good adhesion of the coating to the substrate, to minimize the reactivity between the substrate and the outer glass-ceramic coating and thus to preserve the nature of its crystalline phases. The coated samples were characterised by means of X-ray diffraction (XRD), scanning microscopy (SEM), and compositional analyses (EDS). The bioactivity of the coated samples was studied by soaking them in simulated body fluid (SBF) in order to observe the growth of an apatite layer on their surface. The optimised coating method was then used to coat Ti6Al4V screws for dental applications.