Enhanced osseointegration of Ti6Al4V ELI screws built-up by electron beam additive manufacturing: An experimental study in rabbits

• Published in: Applied surface science 2020-04, Vol.508, p.145160, Article 145160
• Main Authors: Lee, Byoung-Soo, Lee, Hae-Jin, Lee, Kang-Sik, Kim, Hyung Giun, Kim, Gun-Hee, Lee, Chang-Woo
• Format: Article
• Language: English
• Subjects: Additive manufacturing; Bone-to-implant contact; Osseointegration; Surface roughness; Ti6Al4V ELI
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2019.145160

[Display omitted] •The surface roughness, morphologies, and osseointegration are correlated and discussed.•Irregular and micro-rough surface structures drive the osseointegration on Ti6Al4V ELI.•The additively manufactured screws present the higher bone-to-implant contact and an excellent biomechanical performance. In the present study, the osseointegration of additively manufactured screws with a micro-rough surface structure and conventionally machined Ti6Al4V ELI screws with a smooth surface structure is compared. Screws were implanted in rabbit femurs or tibiae for two weeks. The additively manufactured screws exhibited a micro-rough surface with attached semi-molten powder with a size of 50–100 μm and blunt threads, whereas the conventionally machined screws showed a smooth surface and sharp threads. The bonding strength of the additively manufactured screws was significantly higher than that of the conventionally machined screws. The additively manufactured screws showed higher bone-to-implant contact than the conventionally machined screws. Considerable amount of bone tissue on the surface of the additively manufactured screws remained after the push-out tests, and the rabbit tibiae with the additively manufactured screws were significantly damaged, indicating a higher osseointegration rate. Active osteogenesis was observed around the semi-molten powder of the additively manufactured screws, and new bone was well developed along the micro-rough surface. Overall, this study shows that the micro-rough surface improved the bone ingrowth and suggests that additively manufactured screws may be an alternative to conventionally machined screws.