Performance of laser sintered Ti-6Al-4V implants with bone-inspired porosity and micro/nanoscale surface roughness in the rabbit femur

• Type of Material: Article
• Authors: David J. Cohen, Virginia Commonwealth University; Alice Cheng, Emory University; Kaan Sahingur, Virginia Commonwealth University; Ryan M. Clohessy, Virginia Commonwealth University; Louis B. Hopkins, Virginia Commonwealth University; Barbara Boyan, Emory University; Zvi Schwartz, Virginia Commonwealth University
• Language: English
• Date: 2017-04-28
• Publisher: IOS Press
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2017 IOP Publishing Ltd.
• Final Published Version (URL): http://dx.doi.org/10.1088/1748-605X/aa6810
• Title of Journal or Parent Work: Bio-Medical Materials and Engineering
• ISSN: 0959-2989
• Volume: 12
• Issue: 2
• Start Page: 025021
• End Page: 025021
• Grant/Funding Information: This research was supported in part by AB Dental (Ashdod, Israel), which also generously manufactured the implants for this study. Research reported in this publication was also supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health under Award Number AR052102.
• Keywords: animal models; CONSTRUCTS; Materials Science, Biomaterials; TITANIUM IMPLANTS; Engineering; DIFFERENTIATION; osseointegration; TOTAL HIP; additive manufacturing; Technology; surface topography; REPLACEMENT; IN-VITRO; Materials Science; WETTABILITY; Engineering, Biomedical; OSTEOBLAST LINEAGE CELLS; UNITED-STATES; OSSEOINTEGRATION; Science & Technology; dental implants; orthopaedic implants
• Research Categories: Health Sciences, Dentistry; Engineering, Biomedical

Abstract

Long term success of bone-interfacing implants remains a challenge in compromised patients and in areas of low bone quality. While surface roughness at the micro/nanoscale can promote osteogenesis, macro-scale porosity is important for promoting mechanical stability of the implant over time. Currently, machining techniques permit pores to be placed throughout the implant, but the pores are generally uniform in dimension. The advent of laser sintering provides a way to design and manufacture implants with specific porosity and variable dimensions at high resolution. This approach enables production of metal implants that mimic complex geometries found in biology. In this study, we used a rabbit femur model to compare osseointegration of laser sintered solid and porous implants. Ti-6Al-4V implants were laser sintered in a clinically relevant size and shape. One set of implants had a novel porosity based on human trabecular bone; both sets had grit-blasted/acid-etched surfaces. After characterization, implants were inserted transaxially into rabbit femora; mechanical testing, micro-computed tomography (microCT) and histomorphometry were conducted 10 weeks post-operatively. There were no differences in pull-out strength or bone-to-implant contact. However, both microCT and histomorphometry showed significantly higher new bone volume for porous compared to solid implants. Bone growth was observed into porous implant pores, especially near apical portions of the implant interfacing with cortical bone. These results show that laser sintered Ti-6Al-4V implants with micro/nanoscale surface roughness and trabecular bone-inspired porosity promote bone growth and ma y be used as a superior alternative to solid implants for bone-interfacing implants.