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

Stefan Bruns; Diana Krüger; Silvia Galli; D C Florian Wieland; Jörg U Hammel; Felix Beckmann; Ann Wennerberg; Regine Willumeit-Römer; Berit Zeller-Plumhoff; Julian Moosmann

doi:10.1016/j.bioactmat.2023.05.006

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

Bioact Mater. 2023 May 19:28:155-166. doi: 10.1016/j.bioactmat.2023.05.006. eCollection 2023 Oct.

Affiliations

¹ Institute of Metallic Biomaterials, Helmholtz-Zentrum Hereon, Max-Planck-Str. 1, 21502, Geesthacht, Germany.
² University of Malmö, Faculty of Odontology, Department of Prosthodontics, Carl Gustafs Väg 34, Klerken, 20506, Malmö, Sweden.
³ Institute of Materials Physics, Helmholtz-Zentrum Hereon, Max-Planck-Str. 1, 21502, Geesthacht, Germany.
⁴ University of Gothenburg, Institute of Odontology, Department of Prosthodontics, Medicinaregatan 12 f, 41390, Göteborg, Sweden.

Abstract

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.

Keywords: Biodegradable implant materials; Bone mechanical testing; Digital volume correlation; Implant stability; Synchrotron micro-computed tomography imaging.