Mode III cleavage of a coin-shaped titanium implant in bone: effect of friction and crack propagation

Vincent Mathieu (1, 2) , Romain Vayron (2) , Etienne Barthel (3) , Davy Dalmas (3) , Emmanuel Soffer (1, 4) , Fani Anagnostou (1, 4) , Guillaume Haiat (2)

1 B2OA (UMR_7052) - Bioingénierie et Bioimagerie Ostéo-articulaires ; Biomécanique et Biomatériaux Ostéo-Articulaires
2 MSME - Laboratoire de Modélisation et Simulation Multi Echelle
3 SVI - Surface du Verre et Interfaces
4 CHU Pitié-Salpêtrière [AP-HP]

Endosseous cementless implants are widely used in orthopaedic, maxillofacial and oral surgery. However, failures are still observed and remain difficult to anticipate as remodelling phenomena at the bone-implant interface are poorly understood. The assessment of the biomechanical strength of the bone-implant interface may improve the understanding of the osseointegration process. An experimental approach based on a mode III cleavage mechanical device aims at understanding the behavior of a planar bone-implant interface submitted to torsional loading. To do so, coin-shaped titanium implants were inserted on the tibiae of a New Zealand White rabbit for seven weeks. After sacrifice, mode III cleavage experiments were performed on bone samples. An analytical model was developed to understand the debonding process of the bone-implant interface. The model allowed to assess the values of different parameters related to bone tissue at the vicinity of the implant with the additional assumption that bone adhesion occurs over around 70% of the implant surface, which is confirmed by microscopy images. The approach allows to estimate different quantities related to the bone-implant interface such as: torsional stiffness (around 20.5 N.m.rad-1), shear modulus (around 240 MPa), maximal torsional loading (around 0.056 N.m), mode III fracture energy (around 77.5 N.m-1) and stress intensity factor (0.27 MPa.m1/2). This study paves the way for the use of mode III cleavage testing for the investigation of torsional loading strength of the bone-implant interface, which might help for the development and optimization of implant biomaterial, surface treatment and medical treatment investigations.

Mots clés: Bone; Implant; Osseointegration; Mode III; Cleavage

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Biomécanique [physics.med-ph]

Vincent Mathieu, Romain Vayron, Etienne Barthel, Davy Dalmas, Emmanuel Soffer, et al.. Mode III cleavage of a coin-shaped titanium implant in bone: effect of friction and crack propagation. Journal of the mechanical behavior of biomedical materials, 2012, 8, pp.197-203. ⟨10.1016/j.jmbbm.2011.12.012⟩. ⟨hal-00666072⟩