Surface Treatments for Implants Obtained through Additive Manufacturing

Different techniques can fabricate long-term implants made of titanium and its alloys. Conventional manufacturing proceeds by foundry and precise milling, usually with the use of CNC ( Computer Numerical Control ). The other methods include rapidly expanding additive manufacturing (AM) and powder metallurgy. The AM can be executed for titanium by selective laser melting (SLM) or by electron beam machining. As the final result, either solid titanium implants with porous surfaces, scaffolds, or implants with porous outer layers can be obtained. The advantage of such manufacturing is that no productional waste appears, the implant has Young`s modulus closer to that of a bone, and the speed of manufacturing is distinctly higher. For implants obtained by AM, surface treatment is similar to conventional implants. However, the effects are diverse and still under study. The surface modification can be divided into three categories: (i) proceeding with the removal of material, such as grinding and polishing, laser treatment, and chemical etching, (ii) with no materials removal, such as the other types of mechanical treatment, and laser treatment, and (iii) with deposition of coatings. This chapter is focused mainly on coatings as they are important for the enhancement of bioactivity and antibacterial properties. Additionally, the deposition of coatings within the pores of SLM-made implants is challenging yet crucial for implants featuring porous layers or scaffolds.