Nanoindentation Measurements of Biomechanical Properties in Mature and Newly Formed Bone Tissue Surrounding an Implant

Cementless implants are widely used in orthopedic and oral surgery. However, debonding-related failure still occurs at the bone-implant interface. It remains difficult to predict such implant failure since the underlying osseointegration phenomena are still poorly understood. Especially in terms of friction and adhesion at the macro-scale, there is a lack of data and reliable models. The aim of this work is to present a new friction formulation that can model the tangential contact behavior between osseointegrated implants and bone tissue, with focus on debonding. The classical Coulomb's law is combined with a state variable friction law to model a displacement-dependent friction coefficient. A smooth state function, based on the sliding distance, is used to model implant debonding. The formulation is implemented in a 3D nonlinear finite element framework, and it is calibrated with experimental data and compared to an analytical model for mode III cleavage of a coin-shaped, titanium implant [32]. Overall, the results show close agreement with the experimental data, especially the peak and the softening part of the torque curve with a relative error of less than 2.25 %. In addition, better estimates of the bone's shear modulus and the adhesion energy are obtained. The proposed model is particularly suitable to account for partial osseointegration, as is also shown.

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“…21 GPa are in good agreement with experimental data from the literature [35,39] and previous studies [55,56]. In Ref.…”

Section: Parameter Calibrationsupporting

confidence: 91%

A modified Coulomb’s law for the tangential debonding of osseointegrated implants

Immel

Duong

Nguyen

et al. 2020

Biomech Model Mechanobiol

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“…A micro-scale bone tissue modulus of 20GPa for native calvarium, a conservative estimate of 18GPa for regenerated calvarium and 0.3 Poison's ratio 24 was chosen for the analysis based on previous nano-indentation results in a rabbit cranial model 25 . In the defect margin ROI, native and regenerated bone were outlined and the respective micro-scale tissue modulus was applied.…”

Section: Methodsmentioning

confidence: 99%

Sustained Delivery of rhBMP-2 by Means of Poly(Lactic-co-Glycolic Acid) Microspheres

Wink

Gerety

Sherif

et al. 2014

Plastic and Reconstructive Surgery

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Background Commercially available recombinant human bone morphogenetic protein 2 (rhBMP2) has demonstrated efficacy in bone regeneration, but not without significant side effects. In this study, we utilize rhBMP2 encapsulated in PLGA microspheres (PLGA-rhBMP2) placed in a rabbit cranial defect model to test whether low-dose, sustained, delivery can effectively induce bone regeneration. Methods rhBMP2 was encapsulated in 15% poly (lactic-co-glycolic acid), using a double emulsion, solvent extraction/evaporation technique, and its release kinetics and bioactivity were tested. Two critical-size defects (10mm) were created in the calvarium of New Zealand White rabbits (5-7 mos of age, M/F) and filled with a collagen scaffold containing one of four groups: 1) no implant, 2) collagen scaffold only, 3) PLGA-rhBMP2(0.1ug/implant), or 4) free rhBMP2 (0.1ug/implant). After 6 weeks, the rabbits were sacrificed and defects were analyzed by μCT, histology, and finite element analysis. Results RhBMP2 delivered via bioactive PLGA microspheres resulted in higher volumes and surface area coverage of new bone than an equal dose of free rhBMP2 by μCT and histology (p=0.025, 0.025). FEA indicated that the mechanical competence using the regional elastic modulus did not differ with rhBMP2 exposure (p=0.70). PLGA-rhBMP2 did not demonstrate heterotopic ossification, craniosynostosis, or seroma formation. Conclusions Sustained delivery via PLGA microspheres can significantly reduce the rhBMP2 dose required for de novo bone formation. Optimization of the delivery system may be a key to reduce the risk for recently reported rhBMP2 related adverse effects. Level of Evidence Animal Study

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“…Spatial variations of HP and TMD in the femoral hip region induce heterogeneity of cortical bone at the organ scale (Bensamoun et al 2004a, b;Yamato et al 2006;Sasso et al 2007Sasso et al , 2008Mathieu et al 2013). This heterogeneity strongly affects the mechanical response of bone as it was widely documented by studies on ultrasonic wave propagation (Haiat et al 2009(Haiat et al , 2011Naili et al 2010;Grimal et al 2014) and nanoindentation (Yao et al 2011;Vayron et al 2012Vayron et al , 2014.…”

Section: Introductionmentioning

confidence: 97%

Stochastic multiscale modelling of cortical bone elasticity based on high-resolution imaging

Sansalone

Gagliardi

Desceliers

et al. 2015

Biomech Model Mechanobiol

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Accurate and reliable assessment of bone quality requires predictive methods which could probe bone microstructure and provide information on bone mechanical properties. Multiscale modelling and simulation represent a fast and powerful way to predict bone mechanical properties based on experimental information on bone microstructure as obtained through X-ray-based methods. However, technical limitations of experimental devices used to inspect bone microstructure may produce blurry data, especially in in vivo conditions. Uncertainties affecting the experimental data (input) may question the reliability of the results predicted by the model (output). Since input data are uncertain, deterministic approaches are limited and new modelling paradigms are required. In this paper, a novel stochastic multiscale model is developed to estimate the elastic properties of bone while taking into account uncertainties on bone composition. Effective elastic properties of cortical bone tissue were computed using a multiscale model based on continuum micromechanics. Volume fractions of bone components (collagen, mineral, and water) were considered as random variables whose probabilistic description was built using the maximum entropy principle. The relevance of this approach was proved by analysing a human bone sample taken from the inferior femoral neck. The sample was imaged using synchrotron radiation micro-computed tomography. 3-D distributions of Haversian porosity and tissue mineral density extracted from these images supplied the experimental information needed to build the stochastic models of the volume fractions. Thus, the stochastic multiscale model provided reliable statistical information (such as mean values and confidence intervals) on bone elastic properties at the tissue scale. Moreover, the existence of a simpler "nominal model", accounting for the main features of the stochastic model, was investigated. It was shown that such a model does exist, and its relevance was discussed.

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Nanoindentation Measurements of Biomechanical Properties in Mature and Newly Formed Bone Tissue Surrounding an Implant

Cited by 54 publications

References 66 publications

A modified Coulomb’s law for the tangential debonding of osseointegrated implants

A modified Coulomb’s law for the tangential debonding of osseointegrated implants

Sustained Delivery of rhBMP-2 by Means of Poly(Lactic-co-Glycolic Acid) Microspheres

Stochastic multiscale modelling of cortical bone elasticity based on high-resolution imaging

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