RESUMEN
With the development of societies, diabetic foot ulcers have become one of the most common diseases requiring lower extremity amputation. The early treatment and prevention of diabetic foot ulcers can considerably reduce the possibility of amputation. Using footwear to redistribute and relieve plantar pressure is one of the important measures for the treatment and prevention of diabetic foot ulcers. Thus, the evaluation and prediction of the distribution of plantar pressure play an important role in designing footwears. Herein, the finite element method was used to study plantar pressure under two kinds of foot models, namely, the skeletal structure foot model and the whole foot model, to explore the influence of human bones on the pressure of the soles of the feet and obtain accurate foot pressure. Simulation results showed that under the two models, the plantar pressure and the pressure from the footwear with ethylene vinyl acetate were all reduced. The total deformation demonstrated a slight increase. These stresses are very useful as they enable the design of suitable orthotic footwear that reduces the amount of stress in individuals with diabetic foot ulcers.
RESUMEN
OBJECTIVES: This study aimed to fabricate and characterise silanated and titanated nanobarium titanate (NBT) filled poly(methyl methacrylate) (PMMA) denture base composites and to evaluate the behaviour of a titanate coupling agent (TCA) as an alternative coupling agent to silane. The effect of filler surface modification on fracture toughness was also studied. METHODS: Silanated, titanated and pure NBT at 5% were incorporated in PMMA matrix. Neat PMMA matrix served as a control. NBT was sonicated in MMA prior to mixing with the PMMA. Curing was carried out using a water bath at 75°C for 1.5h and then at 100°C for 30min. NBT was characterised via Fourier transform-infrared spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and Brunauer-Emmett-Teller (BET) analysis before and after surface modification. The porosity and fracture toughness of the PMMA nanocomposites (n=6, for each formulation and test) were also evaluated. RESULTS: NBT was successfully functionalised by the coupling agents. The TCA exhibited the lowest percentage of porosity (0.09%), whereas silane revealed 0.53% porosity. Statistically significant differences in fracture toughness were observed among the fracture toughness values of the tested samples (p<0.05). While the fracture toughness of untreated samples was reduced by 8%, an enhancement of 25% was achieved after titanation. In addition, the fracture toughness of the titanated samples was higher than the silanated ones by 10%. CONCLUSION: Formation of a monolayer on the surface of TCA enhanced the NBT dispersion, however agglomeration of silanated NBT was observed due to insufficient coverage of NBT surface. Such behaviour led to reducing the porosity level and improving fracture toughness of titanated NBT/PMMA composites. Thus, TCA seemed to be more effective than silane. CLINICAL SIGNIFICANCE: Minimising the porosity level could have the potential to reduce fungus growth on denture base resin to be hygienically accepTable Such enhancements obtained with Ti-NBT could lead to promotion of the composites' longevity.