Titanium and its alloys have been successfully used as dental and orthopedic biomaterials because of their good mechanical properties, corrosion resistance and biocompatibility with living tissue. However, the bio-inertness of Ti-based implants may inhibit their direct bonding with bone tissue during implantation. Hence, efforts have been made to strengthen the bonding between implant and bone tissue to enhance osseointegration and reduce the healing period mostly, using hydroxyapatite (HA).
HA can be applied on the Ti surface by conventionally adopted methods such as thermal spraying, sputter coating, hot pressing, acid-etching and plasma spraying. Unfortunately, all these methods have some disadvantages, like delimitation of the HA layer from the surface due to the poor bonding between the coating and the substrate.
Plasma Electrolytic Oxidation (PEO) followed by special hydrothermal treatment process is an alternative approach to obtain HA on Ti implant surface. It is formed inside the layer of titanium oxide, so that the coating forms much stronger bonds with the substrate.