Ultrastructure of regenerated bone mineral surrounding hydroxyapatite-alginate composite and sintered hydroxyapatite

► We analyze the ultrastructure of regenerated bone around biomaterials. ► Hydroxyapatite-alginate before and after calcination as biomaterials for bone grafts. ► Hydroxyapatite-alginate before and after calcination presents structural differences. ► Differences in new bone around different biomaterials are found near the interface. ► Crystalline nanospheres are found in mineralizing bone.