Effect of nano-hydroxyapatite on bone morphogenetic protein-2-induced hard tissue formation and dentin resorption on a dentin surface

► A nano-hydroxyapatite collagen composite with bone morphogenetic protein was studied. ► Implanted nano-hydroxyapatite enhanced hard tissue formation on a dentin surface. ► Implanted nano-hydroxyapatite did not accelerate dentin resorption.