Strontium-Zinc conversion coating on magnesium plates for resorbable tack screws in guided bone regeneration:...

Guided bone regeneration (GBR) requires resorbable implants that balance corrosion resistance and biocompatibility. Magnesium (Mg) is a promising candidate, but its rapid degradation necessitates protective coatings. This study develops and characterizes a strontium-zinc (Sr-Zn) conversion coating on Mg plates for resorbable tack screws, evaluating its corrosion resistance, surface properties, and biocompatibility.

Mg plates (20×15×2 mm) were etched with HCl, coated with Sr-Zn via immersion (30 min, pH 3-5), and characterized using SEM, EDX, and FTIR. Corrosion resistance was assessed via potentiodynamic polarization in simulated body fluid (SBF). Biocompatibility was evaluated using MG63 osteoblast cultures, with statistical comparison (Student's t-test, p < 0.05) between coated (Group A) and uncoated (Group B) plates.

SEM revealed a dense, fibrous coating with interconnected pores, enhancing cell adhesion. EDX confirmed Zn (46.6 wt%) and Sr (3.7 wt%) incorporation. FTIR identified hydroxyl/carbonyl groups and metal-oxygen bonds. The coating improved corrosion resistance compared to bare Mg plates. In vitro cell culture assays demonstrated that Sr-Zn conversion-coated Mg plates (Group A) showed comparable cell viability to bare Mg plates (Group B) at all tested time points. Peak cell viability was recorded at 24 hours, with Group A achieving 92.66% and Group B reaching 91% (p = 0.238). This statistically non-significant difference suggests successful biocompatibility of the Sr-Zn coating. The enhanced biocompatibility observed is likely attributed to the coating's improved corrosion resistance.

The Sr-Zn coating improved Mg's corrosion resistance while maintaining osteoblast viability, supporting its potential for resorbable GBR tack screws. Key words:Guided bone regeneration, Magnesium implants, Strontium-zinc coating, Corrosion resistance, Biocompatibility, Resorbable screws.