Surface Characterization of Strontium Phosphate Coating on Magnesium for Mini Implant Applications: A Preliminary in Vitro Study

Background: Magnesium (Mg) implants, known for their biodegradability and mechanical properties, offer significant potential in biomedical applications. However, their rapid corrosion in physiological environments necessitates protective surface coatings. Strontium (Sr) phosphate coatings have emerged as a promising solution due to their ability to enhance corrosion resistance and promote bone growth. This study aimed to evaluate the surface characterization of strontium phosphate coatings on magnesium for mini implant applications. Methods: A total of 170 magnesium samples were coated with strontium phosphate and analyzed over a 4 months period. Surface roughness, coating thickness, chemical composition, and adhesion strength were assessed using profilometry, scanning electron microscopy (SEM), X-ray diffraction (XRD), and pull-off tests, respectively. Data were analyzed using SPSS version 23.0, employing descriptive statistics, t-tests, and ANOVA. Results: The mean surface roughness (Ra) was 1.5 µm (±0.2 µm), and the average coating thickness was 50 µm (±5 µm). Chemical composition analysis revealed 40% Sr, 35% P, 20% O, and 5% Mg. The mean adhesion strength was 30 MPa (±3 MPa). ANOVA tests indicated no significant differences in surface roughness (p = 0.45), coating thickness (p = 0.38), or adhesion strength (p = 0.52) between sample groups. Conclusion: Strontium phosphate coatings on magnesium exhibited consistent surface roughness, coating thickness, chemical composition, and adhesion strength, indicating a reliable coating process suitable for mini implant applications.Recommendations: Further in vivo studies are recommended to evaluate the biological performance and long-term effects of strontium phosphate-coated magnesium implants. Additionally, optimizing the coating process could further enhance the protective and bioactive properties of the coatings.