Investigating Ti-6Al-4V titanium alloy coating using hardstone (Ca2ZnSi2O7) bioactive additives by modified immersion method for use as dental implant

Abstract

Purpose: Applicationof dental implants is increasing worldwide, hence the development of new bioactive materials to improve the properties of dental implants is one of the challenging issues for materials science. In previues studies, a bioactive coating layer, usually compounds based on hydroxyapatite, have been used on dental implants such as titanium alloys. In the current research, the surface of Ti-6Al-4V titanium alloy was coated by hardystonite bioceramic by layering-immersion method and its roughness, biocompatibility, and corrosion were investigated. Methods: In the first step, hardstone powder was prepared, then a suspension consisting of a mixture of these powders and polyvinyl alcohol polymer was prepared as an adhesive. The coatings created were analyzed by scanning electron microscope (SEM) and X-ray (EDAX) devices to investigate the microstructure and determine the composition. To compare the roughness index, samples with ceramic coating with different percentages were examined with an atomic force microscope (AFM). Electrochemical impedance spectroscopy (EIS) method was applied to check corrosion. Cytotoxicity was also measured using MTT assay. Results: The resulting coatings on titanium alloys had very good adhesion and uniformity. The average grain size was 1 to 5 microns. Hardstone particles had a quasi-spherical structure, and all coatings (0.5, 1, 1.5) had proper compression and the least number of cracks. By increasing the weight percentage of hardstone particles, the thickness of the applied coatings on titanium alloys and the surface roughness have increased. The corrosion resistance of the coatings was higher than the control sample. Coatings reduced the rate of corrosion and protected the surface. Hardstoneite had high biocompatibility and low toxicity properties. Conclusion: As a result, according to the desirable characteristics of Ca2ZnSi2O7 coatings, these coatings may be suitable candidates for application in dental implants and other clinical cases.