Additively manufactured medical bone screws: an initial study to investigate the impact of lattice-based Voronoi structure on implant primary stability
ISSN: 1355-2546
Article publication date: 26 September 2023
Issue publication date: 2 January 2024
Abstract
Purpose
The present study investigates the mechanical properties of three types of Ti6Al4V ELI bone screws realized using the laser powder bed fusion (LPBF) process: a fully threaded screw and two groups containing differently arranged sectors made of lattice-based Voronoi (LBV) structure in a longitudinal and transversal position, respectively. This study aims to explore the potentialities related to the introduction of LBV structure and assess its impact on the implant’s primary stability and mechanical performance.
Design/methodology/approach
The optimized bone screw designs were realized using the LPBF process. The quality and integrity of the specimens were assessed by scanning electron microscopy and micro-computed tomography. Primary stability was experimentally verified by the insertion and removal of the screws in standard polyurethane foam blocks. Finally, torsional tests were carried out to compare and assess the mechanical strength of the different designs.
Findings
The introduction of the LBV structure decreases the elastic modulus of the implant. Longitudinal LBV type screws demonstrated the lowest insertion torque (associated with lower bone damage) while still displaying promising torsional strength and removal force compared with full-thread screws. The use of LBV structure can promote improved functional performances with respect to the reference thread, enabling the use of lattice structures in the biomedical sector.
Originality/value
The paper fulfils an identified interest in designing customized implants with improved primary stability and promising features for secondary stability.
Keywords
Acknowledgements
The work was developed in the framework of project N. PR19-PAS-P4 – ADJOINT, funded by INAIL (Istituto Nazionale per l’Assicurazione contro gli Infortuni sul Lavoro). The authors would like to thank Nicola Bennato and Enrico Bassani from CNR ICMATE for their assistance in the experiments.
Conflicts of interest: The authors declare no conflict of interest.
Citation
Bregoli, C., Fiocchi, J., Biffi, C.A. and Tuissi, A. (2024), "Additively manufactured medical bone screws: an initial study to investigate the impact of lattice-based Voronoi structure on implant primary stability", Rapid Prototyping Journal, Vol. 30 No. 1, pp. 60-72. https://doi.org/10.1108/RPJ-10-2022-0363
Publisher
:Emerald Publishing Limited
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