**5. Summary**

Since the first implant was made in the nineteenth century, different prostheses have achieved significant improvements in terms of durability and performance. In addition to the improvements in the design, result of the better knowledge of the biomechanical processes, the development of new materials, and the superficial treatments have been decisive. Hundreds of different materials and dozens of surface treatments which have been studied in a rigorous and systematic way to be used as part of the different types of prostheses. Among all these vast set of materials and treatments, the solutions applied in each type of prosthesis are considerably reduced, as a result of all the research carried out.

In this work, we have reviewed some of the most widespread solutions and have the best results and perspectives of implantation. The thermal injection of HA is currently an extended solution that is applied in different types of implants to significantly increase the osseointegration capacity. PVD coatings by conventional magnetron sputtering techniques are being used to increase corrosion and wear resistance in heart valves and dental implants. In this line, the appearance of improved PVD techniques (HIPIMS) has achieved levels of adhesion and layer density that augur a wide use in other types of implants. Ion implantation and fundamentally the immersion in plasma are very effective tools to increase the wear resistance, maintaining the corrosion resistance of stainless steels and titanium and CoCr alloys.

Although all these techniques, and some more like plasma electrooxidation (PEO), have allowed significant advances already introduced in the market, there are still problems to be solved and challenges to be addressed within the surface treatments and design of novel materials. New manufacturing techniques such as additive manufacturing and social aspects such as the increase in life expectancy, determine that a continuous research is necessary to develop new materials and treatments compatible with this new framework. Probably one of the most promising ways of research is the use of combined treatment techniques within materials and customized designs for each patient.
