Granthamhobbs4484

This article demonstrates our efforts in developing and evaluating all-ceramic, biodegradable composites of calcium phosphate cements (CPCs) reinforced with silver (Ag)-doped magnesium phosphate (MgP) crystals. Two primary goals of this study were to 1) enhance CPC's poor mechanical properties with micro-platelet reinforcement, and 2) impart antibacterial functionalities in composites with the aim to inhibit surgical site infections (SSI). The work embodies three novel features. First, as opposed to well-known reinforcements with whisker or fiber-like morphology, we explored micro-platelets for the first time as the strengthening phase in the CPC matrix. Second, in contrast to conventional polymeric or calcium phosphate (CaP) fibrous reinforcements, newberyite (NB, MgHPO4.3H2O) micro-platelets belonging to the less explored yet promising MgP family, were evaluated as reinforcements for the first time. Third, NB micro-platelets were doped with Ag+ ions (AgNB, Ag content 2 wt%) for enhancing antibacterial functionalities. Results indicated that 1 wt% of AgNB micro-platelet incorporation in the CPC matrix enhanced the compressive and flexural strengths by 200% and 140% respectively as compared to the un-reinforced ones. Besides, antibacterial assays revealed effective bactericidal functionalities (>99% bacteria kill) of the AgNB reinforced CPCs against Escherichia coli. Finally, cytocompatibility studies confirmed favorable pre-osteoblast cell proliferation and differentiation in vitro. Hence, this effort was successful in developing a self-setting and injectable AgNB reinforced CPC composition with favorable mechanical and antibacterial properties.Explant analysis can provide key insights to understanding failures of artificial joints and thus how they might be improved for the ultimate benefit of patients. There are no previous reports of explant analysis of an artificial wrist joint. Rilematovir chemical structure In this study, an explanted metal-on-polymer Maestro wrist was analysed both in macro and nanoscales to estimate its biotribological performance. The articulation was formed between a cobalt chromium carpal head and an ultrahigh molecular weight polyethylene bearing. The surface roughness values of its articulating surfaces and the backside of the articulation were measured. On average, the articulating surface roughness values were calculated as 0.06 ± 0.02 μm and 1.29 ± 0.63 μm for the cobalt chromium carpal head and ultrahigh molecular weight polyethylene bearing, respectively. Both surfaces had negative skewness, indicating a preponderance of valleys. On the articulating surface of the carpal head, light scratches were observed, and no impingement was observed throughout the component. The polymeric surface had a polished appearance. It had unidirectional scratches at the centre of the articulation, pits of different sizes on its articulating surface, and matt white subsurface regions. The backside of the UHMWPE bearing and the convex surface of the radial body that it was sitting on, were found to have average surface roughness values of 4.23 ± 0.69 μm and 5.57 ± 1.05 μm, respectively. The difference in the means was not significant (p > 0.05). Taking the articulating surface roughness values, the lubrication regime that the explanted Maestro wrist operated under in vivo was estimated for varying physiological conditions, i.e. varying loads, entraining velocities and lubricant viscosities. In every case considered, the explant was found to operate under boundary lubrication.This study presents an experimental evaluation of permeability of triply periodic minimal surfaces (TPMS). Permeability is widely used to characterize scaffolds for Tissue Engineering (TE) applications as it gives information about the structure porosity, pore size, tortuosity and pore interconnectivity which have an important impact in cell seeding and proliferation. Three different TPMS structures were used Schwartz Diamond (SD), Gyroid (SG) and Schwartz Primitive (SP), in four different porosity levels (50, 60, 70 and 80%). Overall, the SG scaffold type was determined to be the most permeable one while the SD was the least permeable. Furthermore, the presence of microscopic inertial pressure losses was verified and the Forchheimer's law proved to be a good mathematical tool as a Darcy's law expansion for the calculation of the structure's permeability while the weak-inertia regime was hard to detect or quantify.Dental erosion has become a prevalence disease and attracted increasing attention worldwide. In this research, we quantitatively evaluate the mechanical and morphological changes in the very early stages of softening and weakening of human enamel surfaces induced by soft drinks using atomic force microscopy (AFM). With an increase of the immersion time in soft drinks, we found a significant increase of surface roughness (Rq) of the enamel surface. The prismatic structure of enamel was clearly observed after a 1-h immersion in Coca-Cola®, which shows its strong erosion effect. According to the elastic modulus mapping images obtained by AFM, a considerable decrease of elastic modulus (E) of enamel surface has been found as the enamel surface structures are etched away by soft drinks. A high surface roughness of enamel will result in a high chance of cavities due to easier bacterial adhesion on rougher surface, while a drastic deterioration of the mechanical properties of the enamel will weaken its protection property. Our findings show the serious influence of acidic drinks on enamel surface at the very beginning stage of etching process, which is quite meaningful for people to prevent dental erosion and keep dental health.

To evaluate edge chip resistance (R

) and fractographic features of ceramic systems submitted to edge chipping.

Samples were fabricated using the following materials YZ-yttria-stabilized tetragonal zirconia ceramic (IPS e.max® Zir-CAD); LG-leucite-reinforced glass-ceramic (IPS Empress® CAD); LD-lithium-disilicate glass-ceramic (IPS e.max® CAD); ZF- YZ veneered by a pressable fluorapatite glass-ceramic (IPS e.max® Zir-CAD+IPS e.max® Zir-Press); ZD- YZ-LD fused together by a glass-ceramic (IPS e.max® Zir-CAD+IPS e.max® crystall./connect+IPS e.max® CAD). Half of the sample size was bonded (B) to a dentine analogue substrate (NEMA G10) and the remaining samples were kept non-bonded (NB). Structures were indented (n=25) at different edge distances (d=0.3, 0.4, 0.5, 0.6, 0.7mm) using a universal testing machine to produce chips. Force (F) and d values were recorded and R

was calculated. Data were statistically analyzed using ANOVA, Student t and Tukey tests (α=0.05). Chipping was evaluated visually and under optical and scanning electron microscopy based on fractography principles.