Publications by authors named "Sandra Guerard"
Background/aim: It is difficult to characterize the impact behavior of mouthguards on the basis of their components. Impact behavior tests should be performed on mouthguard formed to simulate their intra-oral performance. The aim of this study was to compare the impact behavior of six models of mouthguards using a standardized experimental protocol.
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- The study focused on how the nonlinear elastic properties of human cortical bone change when a small crack is introduced, using 14 bone specimens and nonlinear resonant ultrasound spectroscopy (NRUS) for measurement.
- A 500 µm crack was created in the specimens, and researchers observed significant increases in the nonlinear elastic coefficient αf after crack propagation, while other parameters remained stable.
- It was found that the nonlinear elastic behavior of the bone is more pronounced in hydrated conditions, and there is a strong correlation between the crack length and the nonlinear elastic parameter αf in both dry and wet conditions.
Article Synopsis
- - Recent advancements in biomaterials have improved artificial ligaments, increasing interest in their use for anterior cruciate ligament (ACL) reconstructions.
- - A study tested four types of femoral ACL fixations using a new system called LARS™ AC, comparing their strength, slippage, and failure modes under static loads.
- - The transversal fixation showed the highest load capacity and potential for better clinical outcomes, even though it experienced more graft slippage compared to other methods tested.
This study examined whether the thermo-modeling process suits the thermal properties of the material constituting mouth-formed mouthguards (MGs). Five mouth-formed MGs were compared: four commercially available MGs (SDI™, Gel Nano™, Opro Shield Gold™, and Kipsta R300™) and one prototype. Differential scanning calorimetry was used to determine melting (T(m)) and crystallization (T(c)) temperatures and specific fusion and crystallization enthalpies (∆H(f) and ∆H(c) (J/g)).
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- The study assessed the effectiveness of nonlinear resonant ultrasound spectroscopy (NRUS) in detecting microdamage in human cortical bone caused by cyclic four-point bending fatigue.
- Bone specimens were subjected to controlled fatigue cycles, and NRUS measurements examined the relationship between nonlinear elastic behavior and microdamage accumulation throughout the process.
- Findings indicated a significant correlation between increases in nonlinear hysteretic elastic behavior and the emergence of short microcracks, suggesting that NRUS can be a valuable tool for monitoring early stages of bone microdamage.
This study investigates the impact of polystyrene sodium sulfonate (PolyNaSS) grafting onto the osseo-integration of a polyethylene terephthalate artificial ligament (Ligament Advanced Reinforcement System, LARS™) used for Anterior Cruciate Ligament (ACL). The performance of grafted and non-grafted ligaments was assessed in vitro by culturing human osteoblasts under osteogenic induction and this demonstrated that the surface modification was capable of up-regulating the secretion of ALP and induced higher level of mineralisation as measured 6 weeks post-seeding by Micro-Computed Tomography. Grafted and non-grafted LARS™ were subsequently implanted in an ovine model for ACL reconstruction and the ligament-to-bone interface was evaluated by histology and biomechanical testings 3 and 12 months post-implantation.
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- This study evaluated the tissue integration and mechanical properties of the LARS artificial ligament used for replacing the anterior cruciate ligament (ACL) in a sheep model.
- Researchers found that tissue ingrowth only happened where the artificial ligament touched native tissues, and 40% of the explanted knees showed ligament wear.
- While the LARS AC performed reasonably well clinically over a year, its mechanical strength was significantly below that of a normal ACL, indicating limitations for complete ACL replacement.
A significant risk of femoral neck (FN) fracture exists for men and women with an areal bone mineral density (aBMD) higher than the osteoporotic range, as measured with dual-energy X-ray absorptiometry (DXA). Separately measuring the cortical and trabecular FN compartments and combining the results would likely be a critical aspect of enhancing the diagnostic capabilities of a new technique. Because the cortical shell determines a large part of FN strength a novel quantitative ultrasound (QUS) technique that probes the FN cortical compartment was implemented.
View Article and Find Full Text PDFA mini-compression jig was built to perform in situ tests on bovine trabecular bone monitored by micro-MRI. The MRI antenna provided an isotropic resolution of 78 microm that allows for a volume correlation method to be used. Three-dimensional displacement fields are then evaluated within the bone sample during the compression test.
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