Leemartensen1840

The study aims to quantify the viscoelastic properties of representative dental CAD/CAM resin-based composites (RBC) and to determine the effects of loading frequencies on the viscoelastic material response in comparison to clinically established CAD/CAM glass ceramics.

Eight RBCs, one leucite-reinforced, and one lithium disilicate glass-ceramics were selected. The quasi-static (indentation hardness H

, indentation modulus, E

) and viscoelastic (storage modulus E', loss modulus E″, loss factor tanδ) material behavior was monitored by a depth-sensing indentation test equipped with a DMA module. A low-magnitude oscillating force was therefore superimposed onto a quasi-static force (F

=1000mN) at 20 different frequencies in the range 1-50Hz. One and multiple-way analysis of variance (ANOVA), the Tukey honestly significant difference (HSD) post-hoc tests (α=0.05), and a Pearson correlation analysis were used for data analysis.

The quasi-static parameters increased with the crystalline phase in glass ceray grain or interphase boundary relaxation. RBCs have better damping capabilities over a wider frequency range. The deviations from the ideal elasticity were significantly lower in the glass ceramics than in the RBCs.

All materials sowed viscoelastic behavior related to their microstructure and the internal friction created by grain or interphase boundary relaxation. RBCs have better damping capabilities over a wider frequency range. The deviations from the ideal elasticity were significantly lower in the glass ceramics than in the RBCs.Unlike liquid phase colloidal assembly, significantly changing the structure of fractal aggregates in the aerosol phase, is considered impractical. In this study, we discuss the possibility of applying external magnetic and electric fields, to tune the structure and fractal dimension (Df) of aggregates grown in the aerosol phase. We show that external fields can be used to induce dipole moments in primary nanoparticles. We found that an ensemble of particles with induced dipole moments will interact through directional attractive and repulsive forces, leading to the formation of linear, chain-like aggregates with Df ~ 1. The aggregate structure transition is dependent on the primary particle sizes, temperature and applied field strength which was evaluated by performing a hybrid ensemble/cluster-cluster aggregation Monte Carlo simulation. We demonstrate that the threshold magnetic field strength required to linearly assemble 10-500 nm particle sizes are practically achievable whereas the electric field required to assemble sub-100 nm particles are beyond the breakdown strength of most gases. To theoretically account for the enhanced coagulation rates due to attractive interactions, we have also derived a correction factor to both free molecular and transition regime coagulation kernel, based on magnetic dipolar interactions. A comparison has been made between the coagulation time-scales estimated by theory and simulation, with the estimated magnetization time-scales of the primary particles along with oscillation time period of the magnetic field, to demonstrate that sub-50 nm superparamagnetic primary particles can be magnetized and assembled at any temperature, while below the Curie temperature ferromagnetic particles of all sizes can be magnetized and assembled, given the applied field is higher than the threshold.Small bone defects can heal spontaneously through the bone modeling process due to their physiological environmental conditions. The bone modeling cycle preserves the reliability of the skeleton through the well-adjusted activities of its fundamental cell. Stem cells are a source of pluripotent cells with a capacity to differentiate into any tissue in the existence of a suitable medium. The concept of bone engineering is based on stem cells that can differentiate into bone cells. Mesenchymal stromal cells have been evaluated in bone tissue engineering due to their capacity to differentiate in osteoblasts. They can be isolated from bone marrow and from several adults oral and dental tissues such as permanent or deciduous teeth dental pulp, periodontal ligament, apical dental papilla, dental follicle precursor cells usually isolated from the follicle surrounding the third molar, gingival tissue, periosteum-derived cells, dental alveolar socket, and maxillary sinus Schneiderian membrane-derived cells. Therefore, a suitable animal model is a crucial step, as preclinical trials, to study the outcomes of mesenchymal cells on the healing of bone defects. We will discuss, through this paper, the use of mesenchymal stem cells obtained from several oral tissues mixed with different types of scaffolds tested in different animal models for bone tissue engineering. We will explore and link the comparisons between human and animal models and emphasized the factors that we need to take into consideration when choosing animals. The pig is considered as the animal of choice when testing large size and multiple defects for bone tissue engineering.

Pain can impair functional status, including a patient's ability to return to work. The purpose of this study was to determine whether there was an association between pain levels and return-to-work status during the first 4days post-ED discharge in ED patients seen for undifferentiated acute pain.

This secondary analysis of data from the Acute Management of Pain from the Emergency Department (AMPED) registry included patients who reported working either full-time or part-time. selleck compound We used Cox regression models to examine the association between daily self-reported minimum and maximum pain scores and first return to work. We used repeated measures logistic regression models to examine the association between daily minimum and maximum pain scores and daily return-to-work status.

Of the 610 employed patients, 481 (78.9%) were employed full-time and 129 (21.1%) part-time. The average delay in returning to work after ED visit was 2.4days. For all models, higher minimum and maximum daily pain scores predicted lower daily return-to-work rates in the first four days post-ED discharge. The adjusted hazards ratios for first return to work were 0.91 (0.87, 0.96) and 0.93 (0.89, 0.97), while the adjusted odds ratios for daily return-to-work status were 0.80 (0.75, 0.85) and 0.88 (0.83, 0.93) for every one-point increase in minimum and maximum pain scores, respectively.

Higher daily pain severity is associated with decreased return-to-work after ED visits for acute pain, highlighting the importance of adequate discharge pain management from the ED.

Higher daily pain severity is associated with decreased return-to-work after ED visits for acute pain, highlighting the importance of adequate discharge pain management from the ED.