نتایج جستجو برای: elastic cement
تعداد نتایج: 98023 فیلتر نتایج به سال:
BACKGROUND AND PURPOSE Many clinical reports have indicated that polished hip stems show better clinical results than rough stems of the same geometry. It is still unknown, however, what the mechanical effects are of different surface finishes on the cement at the cement-bone interface. We compared mechanical effects in an in vitro cemented hip arthroplasty model. METHODS Two sizes of double-...
Distal flow of polymethylmethacrylate (PMMA) bone cement during insertion of the femoral implant results in reduced pressure and cement-bone interdigitation (Markolf, Amstutz, 1976). Insertion of femoral cement plugs in the intramedullary canal to prevent distal flow of PMMA cement in total hip replacement during cementing of femoral prostheses is well accepted and has become current practice (...
Portland cement for high-temperature geothermal applications typically includes 35 to 40 percent crystalline quartz by weight of cement (BWOC) to avoid strength retrogression, which is defined as an increase in permeability and a decrease in compressive strength. Also, because of the reactivity of Portland cement at elevated temperatures, relatively expensive cement-hydration retarders are requ...
We investigate the performance of graphene oxide (GO) in improving mechanical properties of cement composites. A polycarboxylate superplasticizer was used to improve the dispersion of GO flakes in the cement. The mechanical strength of graphene-cement nanocomposites containing 0.1-2 wt% GO and 0.5 wt% superplasticizer was measured and compared with that of cement prepared without GO. We found t...
BACKGROUND Pedicle screws with PMMA cement augmentation have been shown to significantly improve the fixation strength in a severely osteoporotic spine. However, the efficacy of screw fixation for different cement augmentation techniques, namely solid screws with retrograde cement pre-filling versus cannulated screws with cement injection through perforation, remains unknown. This study aimed t...
The cement-in-cement technique is useful in the setting of revision total hip arthroplasty (THA), especially to gain acetabular exposure, change a damaged or loose femoral component, or change the version, offset, or length of a fixed femoral component. The goal of this retrospective study was to assess the clinical and radiographic characteristics of revision THA using the cement-in- cement te...
After cemented total hip arthroplasty (THA) there may be failure at either the cement-stem or the cement-bone interface. This results from the occurrence of abnormally high shear and compressive stresses within the cement and excessive relative micromovement. We therefore evaluated micromovement and stress at the cement-bone and cement-stem interfaces for a titanium and a chromium-cobalt stem. ...
Acrylic bone cement is self-curing cement comprising of liquid and powder component of methyl methacrylate (MMA). It has been used extensively in orthopedics; however, adverse effects were associated with its use. Hence we investigated in this paper the possibility of new cement utilizing methacrylates with lower toxicity than MMA. LD50s of candidate monomers were determined with administration...
Nano-Silica Sol-Gel and Carbon Nanotube Coupling Effect on the Performance of Cement-Based Materials
Carbon nanotubes (CNTs) have shown promise for improving the mechanical performance of cement composites through crack-bridging and frictional pull-out. The interactive behaviors between CNTs and cement matrix act are crucial in optimizing the reinforcement of CNTs in cement composites. This study investigates the effects of nano-silica (NS) sol-gel on the interactive behaviors of CNTs and the ...
The initial composition of acrylic bone cement along with the mixing and delivery technique used can influence its final properties and therefore its clinical success in vivo. The polymerisation of acrylic bone cement is complex with a number of processes happening simultaneously. Acrylic bone cement mixing and delivery systems have undergone several design changes in their advancement, althoug...
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