Bioactive Glasses as Alternatives to Hydroxyapatite for Bone Implant Coatings: A Comparative Study

No material currently matches the remodeling rates of natural bone. Although hydroxyapatite is commonly employed as a bioactive coating material for implants, its resorption rate is relatively low. Conversely, bioactive glass materials offer versatility, as they can be tailored with various oxides and proportions to alter their structure and, consequently, their properties. This study examines various bioactive glasses as potential alternatives to hydroxyapatite coatings used in bone implants. Coatings were fabricated using commercial compositions, 45S5 and S53P4, and the 62W composition, which is not yet commercially available. Atmospheric Plasma Spray was utilized to deposit the different bioactive materials onto titanium alloy substrates. The coatings obtained underwent analysis via scanning electron microscopy and x-ray diffraction. It was observed that all bioactive glass coatings exhibited an amorphous structure, with the 62W coating showing less porosity. Mechanical and in vitro tests were conducted to assess their properties. The composition of the bioactive glasses significantly influenced the bond strength and bioactive capacity of the coatings, as well as the cellular response of the coating. The study suggests that bioactive glasses, especially the 62W composition, represent a considerable alternative as coating material.