Levinehelms0188

Purpose The objectives of this study were to evaluate the load bearing capacity of RBFDPs made of different materials after cyclic loading, and classify the failure types after loading. Materials and methods Sound human mandibular first premolars and first molar pairs (N = 60 per tooth type, n = 10 per group) were randomly divided into six experimental groups to receive one of the following inlay-retained RBFDP types RC Resin composite only, DFRC Direct E-glass fiber-reinforced composite (FRC), IFRC Indirect E-glass FRC, LS Lithium disilicate glass-ceramic, ZR Yttria-stabilized tetragonal zirconia, MC Metal-ceramic. Box preparations were made in abutment teeth using diamond burs followed by standardized ultrasonic burs. The teeth were conditioned employing an etch-and-rinse adhesive system and the indirect RBFDPs were cemented adhesively. The specimens were subjected to cyclic loading for x1.200.000 in distilled water alternating between 5 and 55 °C (Zurich Chewing Simulator). They were then loaded to failure DFRC, IDRC and MC did not show any debonding from the abutment teeth. Conclusion Considering load bearing capacity, repairable failure types and Weibull moduli, lithium disilicate seem to be more durable than those of other material options for posterior inlay-retained RBFDPs. Due to early debondings and catastrophic irreparable failure types, zirconia RBFDPs should be indicated with caution in the posterior region.Sol-gel chemistry offers a flexible, widely accepted methodology that enables the creation of a new generation of bioactive glass (BG). In the current study, a sol-gel method was used to synthesize ZrO2 incorporated 56SiO2-34CaO-10P2O5 mol% bioactive glass. The highly crystalline structure was composed of small zirconium oxide nanoparticles (ZrO2) of less than 200 nm in size. It was successfully fabricated using a hydrothermal method. Polyurethane foam (PU) was selected to fabricate a highly porous BG-ZrO2 scaffold using a foam replica technique. The physicochemical, morphological properties of the BG-ZrO2 compositions were evaluated using X-ray diffraction (XRD), Fourier transforms infrared (FTIR), thermo-gravimetric analysis (TGA), transmission electron microscope (TEM) and scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS). In-vitro degradation analysis of the BG-ZrO2 scaffolds was performed after immersion of the samples in simulated body fluid (SBF). The incorporation of ZrO2 nanoparticles into the bioactive glass matrix enhances both the mechanical strength and thermal stability. Since the novel formed BG-ZrO2 scaffolds possesses respectable antibacterial properties against some bacterial strains, this renders it an ideal tissue engineering substitute, capable of reducing failure rates in implants.Due to its unique and advantageous material properties, polyetheretherketone (PEEK) is an attractive biomaterial for implantable devices. Though concerns exist regarding PEEK for orthopaedic implants due to its bioinertness, the creation of porous networks has shown promising results for interaction with surrounding tissue. In this study, we created porous PEEK via clinically-available fused filament fabrication (FFF, 3D printing) and assessed the pore structure morphology, mechanical properties, and biologic response. The designs of the porous structures were based on a simple rectilinear pattern as well as triply periodic minimal surfaces (TPMS), specifically gyroid and diamond types. The material characteristics, including porosity, yield strength, and roughness, were evaluated using μCT, static compression testing, and optical profilometry. The porous PEEK, along with 3D printed solid PEEK, was then seeded with MC3T3-E1 preosteoblast cells for evaluation of cell proliferation and alkaline phosphatase (ALP) activity. The samples were then imaged via scanning electron microscopy (SEM) to observe cell morphology. μCT imaging showed the porous networks to be open and interconnected, with porous sizes similar (p > 0.05) to the as-designed size of 600 μm. Average compressive properties ranged from 210 to 268 MPa for elastic modulus and 6.6-17.1 MPa for yield strength, with strength being greatest for TPMS constructs. SEM imaging revealed cells attaching to and bridging micro-topological features of the porous constructs, and cell activity was significantly greater for the porous PEEK compared to solid at multiple time points.An exceptional tear resistance is required of the skin to protect the body from external attacks, environmental damage, and other forms of aggression. To estimate the toughness of juvenile porcine skin, we conduct two types of experiments on pre-notched specimens, placing the tissue under shear (Mode III) by using the classical trouser test with a 25 mm long pre-notch, and opening (Mode I) with an experimental setup with the same pre-notch length. We obtain two distinct average toughness values of JIIIc≈20.4kJ/m2 and JIc=30.4kJ/m2, as a result of differences between these two modes of crack-tip loading and propagation, and collagen alignment. Digital image correlation coupled with single edge notch tests of 10 mm × 30 mm skin samples enables the mapping of the local strains around the tip of the crack. Effects of sample orientation and initial notch size ratio on the strain profile and on the net-section failure stress are discussed. The evaluation of the structure at the crack tip and regions undergoing more uniform states of deformation is conducted by ex situ transmission electron microscopy and in situ environmental scanning electron microscopy. Prior to crack propagation, the stress concentration is decreased by redistributing loads away from the crack tip, illustrated by gradual recruitment of collagen fibers ahead of the crack tip, thus delaying crack growth. this website After the crack has propagated, collagen fibers are substantially damaged, marked by delamination and recoil of the collagen fibrils.Objectives The aim of this study was to evaluate the effect of hydrothermal aging on the mechanical properties and translucency of dental zirconia with different levels of translucency. Methods Three different types of dental yttria-stabilized zirconia were used 3Y-TZP (ZrO2 - 3 mol.% Y2O3) of medium opacity (designated Z3OP), 3Y-TZP of medium translucency (Z3MT), and 5Y-PSZ (ZrO2 - 5 mol.% Y2O3) of high translucency (Z5HT). A total of 120 specimens were sintered (n = 40 specimens/group). The control group (sintered→polished→heat-treated) and the aged group (sintered→polished→heat-treated→hydrothermally degraded at 134 °C, 2 bar, 5h) were characterized by relative density, quantitative phase analysis by X-ray diffraction using the Rietveld method, microstructural analysis by scanning electron microscopy, surface roughness and translucency. All groups were submitted to a biaxial flexural strength test. Data analysis using Kruskal-Wallis, Nemenyi (p-value = 0.05), and Weibull statistics were used. Results All sintered specimens presented full densification.