Evaluation of biodegradability of titanium disk surface coating with hydroxyapatite-gelatin nano-composites

Abstract

Introduction: In the last decade, implant surfaces have been developed in a double effort to provide bone in the process of fast osseointegration of the implant inside the bone and to improve the properties of the biological surfaces of the implant. The change in the surface coating of the implant has shown a significant osteoblastic response in the laboratory and in vivo studies. The surface characteristics of the implant affect the amount of osseointegration and biomechanical stability and induce the appropriate response of the implant with the bone. The present study aims to evaluate the biodegradability of titanium disk surface coating with hydroxyapatite-gelatin nanocomposites. Materials and Methods: 26 grade 2 titanium pieces were used as a substrate in this experimental study. These substrates were first cleaned by ultrasonic for 20 minutes, then placed in 70% ethanol solution for 20 minutes, and finally in distilled water for 15 minutes. The dip coating process was applied to cover the surface. A scanning electron microscope (SEM) was used to investigate the microstructure and morphology of the coatings, and X-rays (EDAX) were used to determine the composition of the coatings. The biodegradability test was performed in SBF solution at 37°C. SEM qualitatively examined morphological changes before and after coating, 14 days, and 28 days after coating. Changes in the weight ratio of discs before and after coating were also quantitatively investigated. Results: The average weight of the discs in the examined samples at the initial times, immediately, 14 days, and 28 days after coating was 1.365 ± 0.003 grams, 1.515 ± 0.017 grams, 1.511 ± 0.018 grams, and 1.496 ± 0.020 grams; respectively. The variance analysis results showed that the changes in the average weight of discs over time were statistically significant (p-value<0.001). Based on the Sidak test results, it was observed that only the weight between the two times immediately after coating and 14 days after coating was not statistically significant. Conclusion: The results showed that the coating of hydroxyapatite-gelatin nanocomposites on the disk was successful, and this coating lasted for at least 14 days. This was an important study for coating and evaluating the stability of the coating, and it is necessary to carry out further evaluations in different physicochemical, mechanical, and antimicrobial fields.