Evaluation of Biological Properties of Electron Beam Melted Ti6Al4V Implant with Biomimetic Coating In Vitro and In Vivo

Abstract

BackgroundHigh strength porous titanium implants are widely used for the reconstruction of craniofacial defects because of their similar mechanical properties to those of bone. The recent introduction of electron beam melting (EBM) technique allows a direct digitally enabled fabrication of patient specific porous titanium implants, whereas both their in vitro and in vivo biological performance need further investigation.MethodsIn the present study, we fabricated porous Ti6Al4V implants with controlled porous structure by EBM process, analyzed their mechanical properties, and conducted the surface modification with biomimetic approach. The bioactivities of EBM porous titanium in vitro and in vivo were evaluated between implants with and without biomimetic apatite coating.ResultsThe physical property of the porous implants, containing the compressive strength being 163 - 286 MPa and the Young’s modulus being 14.5–38.5 GPa, is similar to cortical bone. The in vitro culture of osteoblasts on the porous Ti6Al4V implants has shown a favorable circumstance for cell attachment and proliferation as well as cell morphology and spreading, which were comparable with the implants coating with bone-like apatite. In vivo, histological analysis has obtained a rapid ingrowth of bone tissue from calvarial margins toward the center of bone defect in 12 weeks. We observed similar increasing rate of bone ingrowth and percentage of bone formation within coated and uncoated implants, all of which achieved a successful bridging of the defect in 12 weeks after the implantation.ConclusionsThis study demonstrated that the EBM porous Ti6Al4V implant not only reduced the stress-shielding but also exerted appropriate osteoconductive properties, as well as the apatite coated group. The results opened up the possibility of using purely porous titanium alloy scaffolds to reconstruct specific bone defects in the maxillofacial and orthopedic fields.

Maintenance of a bone collagen phenotype by osteoblast-like cells in 3D periodic porous titanium (Ti-6Al-4 V) structures fabricated by selective electron beam melting

“…However, Huiskes has maintained that with longer implant lifetimes, bone remodeling due to stress shielding will become an important issue making revision surgeries more difficult (46). The EBM-processed scaffolds described here have mechanical properties within the range of cortical and cancellous bone (21) and is in concurrence with recent observations by Li et al (50). Porous titanium scaffolds could be effective for use in physiologically optimized load bearing and non-load bearing bone replacement implants.…”

Laser and electron‐beam powder‐bed additive manufacturing of metallic implants: A review on processes, materials and designs

“…In vivo histological analysis has obtained a rapid in‐growth of bone tissue from calvarial margins toward the center of bone defect in 12 weeks. They found that the bone in‐growth within the implant with or without apatite coating was quite similar, which means the implants can be directly used without surface modifications …”

In vitro and in vivo biocompatibility of an Ag-bearing Zr-based bulk metallic glass for potential medical use

“…In this regard, a number of titanium alloys were developed for biomedical applications. Ti-6Al-4V alloy, originally developed as an aeronautical material, has been tested as a replacement for pure Ti, because of its higher strength with sufficient corrosion resistance [61]. However, extensive investigations have shown that the release of V ion from the Ti-6Al-4V alloy to the human body might cause long-term health problems, such as peripheral neuropathy, and osteomalacia diseases [62].…”