On the material dependency of peri-implant morphology and stability in healing bone

• Published in: Bioactive materials Vol. 28; pp. 155 - 166
• Main Authors: Bruns, Stefan, Krüger, Diana, Galli, Silvia, Wieland, D.C. Florian, Hammel, Jörg U., Beckmann, Felix, Wennerberg, Ann, Willumeit-Römer, Regine, Zeller-Plumhoff, Berit, Moosmann, Julian
• Format: Journal Article
• Language: English
• Published: China Elsevier B.V 01.10.2023; KeAi Publishing; KeAi Communications Co., Ltd
• Subjects: aging; Biodegradable implant materials; Bone mechanical testing; Digital volume correlation; Implant stability; Synchrotron micro-computed tomography im; Synchrotron micro-computed tomography imaging; Digital volume correlation; Biodegradable implant materials; Synchrotron micro-computed tomography imaging; Implant stability; Bone mechanical testing
• ISSN: 2452-199X; 2452-199X
• DOI: 10.1016/j.bioactmat.2023.05.006

The microstructural architecture of remodeled bone in the peri-implant region of screw implants plays a vital role in the distribution of strain energy and implant stability. We present a study in which screw implants made from titanium, polyetheretherketone and biodegradable magnesium-gadolinium alloys were implanted into rat tibia and subjected to a push-out test four, eight and twelve weeks after implantation. Screws were 4 mm in length and with an M2 thread. The loading experiment was accompanied by simultaneous three-dimensional imaging using synchrotron-radiation microcomputed tomography at 5 μm resolution. Bone deformation and strains were tracked by applying optical flow-based digital volume correlation to the recorded image sequences. Implant stabilities measured for screws of biodegradable alloys were comparable to pins whereas non-degradable biomaterials experienced additional mechanical stabilization. Peri-implant bone morphology and strain transfer from the loaded implant site depended heavily on the biomaterial utilized. Titanium implants stimulated rapid callus formation displaying a consistent monomodal strain profile whereas the bone volume fraction in the vicinity of magnesium-gadolinium alloys exhibited a minimum close to the interface of the implant and less ordered strain transfer. Correlations in our data suggest that implant stability benefits from disparate bone morphological properties depending on the biomaterial utilized. This leaves the choice of biomaterial as situational depending on local tissue properties. [Display omitted] •Push-out test of screw implants imaged dynamically in 3D using micro computed tomography.•Quantitative comparison of bone implant stability for titanium, PEEK and biodegradable magnesium-gadolinium alloys.•Implant stability depends on implant materials and bone morphology-dependent load transfer.