1,046 research outputs found
Do nanofilled/nanohybrid composites allow for better clinical performance of direct restorations than traditional microhybrid composites? a systematic review
This systematic review was carried out to assess the clinical effectiveness of nanofilled and nanohybrid composites used for direct restorations in comparison with microhybrid composites. The guidelines for the preferred reporting items for systematic reviews and meta-analyses were followed. A search of articles published from July 1996 to February 2017 was performed in PubMed, SciVerse Scopus, Latin American and Caribbean Health Sciences, the Scientific Electronic Library Online, and the Cochrane Library. The present review selected only randomized controlled trials comparing the clinical performance of a nanofilled or nanohybrid composite for direct restorations with that of a microhybrid composite. The research found 201 studies. Twenty-one articles fulfilled the criteria of the present review. However, the included studies were characterized by great methodological diversities. As a general trend, nanofilled and nanohybrid composites were found to be capable of clinical performance, marginal quality, and resistance to wear similar to that of traditional composites without showing improved surface characteristics. The risk of bias of included studies was judged unclear or high. The clinical performance of nanofilled/nanohybrid composites was found to be comparable to that of traditional composites in the posterior area. The data concerning anterior and cervical restorations were insufficient. With regard to the esthetic properties, there is a compelling need for studies on anterior teeth in which the operators are kept unaware of the restorative material. Nanofilled/nanohybrid composites seem to be a valid alternative to traditional microhybrid composites, and at the moment, there is low-level evidence attesting a lack of their superiority
Evaluation of degree of conversion, rate of cure, microhardness, depth of cure and contraction stress of three nano hybrid composites containing pre-polymerized spherical filler
Aim: Manufacturers aim at improving filler technology to enhance the properties of the restorative materials, thus maximising the aesthetic and functional outcome of the restored tooth. The present study tested the degree of conversion (DC), rate of cure (RC), microhardness (VHN), depth of cure (VHR) and contraction stress (CS) of three new nano hybrid composites with pre-polymerized spherical filler. Methods: Three commercially available composite resin were characterised in the present study, namely the Ceram.X\uae universal shade A3 (CXUA3), Ceram.X\uae duo enamel shade E2, and Ceram.X\uae duo dentin shade D3 (CXDE2 and CXDD3). The materials were light-cured
with a LED light (SmartLite Focus, measured output 1301 mW/cm2) following the protocol recommended by the manufacturer. DC was assessed by means of Fourier-transform infrared spectroscopy, calculating RC from a second-grade polynomial fitting of the kinetic curve. A microhardness testing machine equipped with a Vickers indenter served to measure the top and bottom VHN of 2 mm-high disc-shaped specimens, using the bottom/top surface values ratio (VHR) as indirect evaluation of the depth of cure. CS vs time was evaluated by a universal testing machine provided with an extensometer as feedback system, CS was normalized for the specimen bonding area. All data sets underwent statistical analysis with dedicated software and tested for the assumptions for the use of parametric tests. Multiple analyses of variance with
Scheff\ue9 post hoc test were carried out to compare the dependent variables of interest among the tested materials. Results: All tested materials exhibited a DC lower than
50%, with CXUA3 reaching the lowest DC value after 10 s. RC of CXUA3 at 5 s was comparable to that of CXDE2, while after 10s RC of CXUA3 decreased to a value proportional to that of CXDD3. For all the tested materials, top-VHN was greater than bottom-VHN. Top-VHN of CXDE2 was lower than CXUA3 and CXDD3. CXDD3 was the only material achieving VHR>80%. The main differences in CS among the tested materials were found during the irradiation with curing-light: CXDE2 displaying the lowest CS after 10 s and CXDD3 the highest after 30 s. Conclusion: The present study proved that the light curing protocol suggested by the manufacturer for the three composites might be improved: 10 s of irradiation seemed insufficient to adequately cure CXUA3 and CXDE2. Longer curing times for these materials appear advisable
Tomato ionomic approach for food fortification and safety.
Food fortification is an issue of paramount of importance for people living both in developed
and in developing countries. Among substances listed as "nutriceuticals", essential minerals have
been recognised for their involvement in several healthy issues, involving all ages. In this frame,
food plants are playing a pivotal role since their capability to compartmentalise ions and proteinmetal
complexes in edible organs. Conversely, the accumulation of high metal levels in those
organs may lead to safety problems. In the recent years, thanks to the availability of new and
improved analytical apparatus in both ionic and genomic/transcrittomics areas, it is became feasible
to couple data coming from plant physiology and genetics. Ionomics is the discipline that studies
the cross-analysis of both data sets. Our group, in the frame of GenoPom project granted by MiUR,
is interested to study the ionomics of tomatoes cultivars derived by breeding programmes in which
wild relatives have been used to transfer several useful traits, such as resistance to biotic or abiotic
stresses, fruit composition and textiture, etc. The introgression of the wild genome into the
cultivated one produces new gene combinations. They might lead to the expression of some traits,
such as increased or reduced adsorption of some metals and their exclusion or loading into edible
organs, thus strongly involving the nutritional food value. Our final goal is to put together data
coming from ions homeostasis and gene expression analyses, thus obtaining an ionomic tomato
map related to ions absorption, translocation and accumulation in various plant organs, fruits
included. To follow our hypothesis, we are studying the ionome of Solanum lycopersicum cv. M82
along with 76 Introgression Lines (ILs) produced by interspecific crosses between this cultivar and
the wild species S. pennellii. These ILs are homozygous for small portions of the wild species
genome introgressed into the domesticated M82 one. They are used as a useful tool for mapping
QTL associated with many traits of interest. It is worthy to note that, until now, little information is
available on QTL for ions accumulation in tomato. Moreover, as our knowledge, effects of new
gene combinations in introgressed lines on ions uptake related to food safety have not been
extensively studied. In this presentation we show results coming from the ionome analysis, carried
out on S . lycopersicum M82 and several ILs. Plants were grown in pots in a greenhouse and
watered with deionised water Thirty day-old plants were left to grow for 15 days in the presence of
non-toxic concentration of Cd, Pb, As, Cr and Zn given combined. Leaves of all plants were then
harvested and stored at -80°C for ionome and gene expression analyses. Preliminary results of
ionome analysis of S. lycopersicum M82 and several ILs, carried out using an ICP-MS, showed that
traits correlated to toxic metals and micronutrients accumulation in apical leaves were significantly
modified in response to specific genetic backgrounds. Those results are perhaps due to the
introgression of traits linked to uptake, translocation and accumulation of useful and/or toxic metal
into plant apical leaves and to interactions of the wild type introgressed genomic regions with the
cultivated genome. Also, data are shown on the identification and isolation of Solanum gene
sequences related to ions uptake, translocation and accumulation, useful for further real-time gene
expression evaluation in both cultivated and ILs during the treatments with the above-mentioned
metals
Use of reciproc instruments with different motions: cyclic fatigue testing with simulation of the body temperature
Aim: To assess the influence of different motions on the cyclic fatigue resistance of Reciproc instruments simulating the temperature of the clinical conditions. Methods: The sample size was determined using statistical software set with the following parameters: \u3b1=0.05, \u3b2=0.20, \u3b4=30.0, \u3c3=28.0. The experiment required 54 Reciproc files. Brand new R25 files were randomly allocated to three groups defined by the tested motion: continuous rotation at 300 rpm (n=18), \u201cRECIPROC\u201d mode (n=18), and \u201cWAVEONE\u201d mode (n=18). The same endodontic motor was used for all groups (X-Smart IQ). All files were rotated/reciprocated until fracture inside a custom-designed artificial canal with 60\ub0 angle and 5-mm radius of curvature milled in a stainless-steel block. The testing device was electrically heated to keep its internal temperature at 35\ub11\ub0C, which was constantly monitored with a thermometer. After file separation, the time to failure was registered with a digital chronometer and the length of the fractured fragment measured with a digital calliper. The fracture surface of each file was observed at the scanning electron microscope to perform a qualitative fractographic analysis. The
collected data (time to fracture and fracture length) were tested for the normality of the distribution and the equality of variances with a Shapiro-Wilk and a Levene test, respectively. The dependent variables were compared amongst groups by means of a multivariate analysis of variance and Tuckey post-hoc test (p=0.05). Results: The continuous rotation group exhibited the shortest lifespan among the considered groups (85.4\ub19.5 s to failure). Both reciprocating motions were associated with a significant improvement of fatigue resistance (p<0.001). The \u201cRECIPROC\u201d mode allowed for longer time to failure than the \u201cWAVEONE\u201d mode, with 141.6\ub119.4 s and 117.2\ub111.2 s to failure, respectively. The absence of differences among the considered groups in terms of fracture length confirmed the correct positioning of the files inside the artificial canal. The scanning electron microscopic analysis showed signs of file separation ascribable to cyclic fatigue. Conclusion: The present study preliminary demonstrated
that the native \u201cRECIPROC\u201d motion use of R25 Reciproc files should be preferred over other types of motions to prevent file separation in the clinical setting
Reducing Teen Substance Misuse: What Really Works 2015
A significant number of students try alcohol, tobacco or other drugs as teenagers. More than 65 percent of students have used alcohol, more than 40 percent used illegal drugs and around one-quarter used cigarettes at some point before entering or while in high school. While the number of teens who regularly misuse or develop substance use disorders has been decreasing over time, overall levels are still too high. In this report, the Trust for America's Health (TFAH) examines how to help move towards a strong prevention-oriented, continuum-of-care approach to substance misuse -- looking at policies and programs that have a high impact for improving the well-being of America's youth
The Interplay between Antibiotics and the Host Immune Response in Sepsis: From Basic Mechanisms to Clinical Considerations: A Comprehensive Narrative Review
Sepsis poses a significant global health challenge due to immune system dysregulation. This narrative review explores the complex relationship between antibiotics and the immune system, aiming to clarify the involved mechanisms and their clinical impacts. From pre-clinical studies, antibiotics exhibit various immunomodulatory effects, including the regulation of pro-inflammatory cytokine production, interaction with Toll-Like Receptors, modulation of the P38/Pmk-1 Pathway, inhibition of Matrix Metalloproteinases, blockade of nitric oxide synthase, and regulation of caspase-induced apoptosis. Additionally, antibiotic-induced alterations to the microbiome are associated with changes in systemic immunity, affecting cellular and humoral responses. The adjunctive use of antibiotics in sepsis patients, particularly macrolides, has attracted attention due to their immune-regulatory effects. However, there are limited data comparing different types of macrolides. More robust evidence comes from studies on community-acquired pneumonia, especially in severe cases with a hyper-inflammatory response. While studies on septic shock have shown mixed results regarding mortality rates and immune response modulation, conflicting findings are also observed with macrolides in acute respiratory distress syndrome. In conclusion, there is a pressing need to tailor antibiotic therapy based on the patient's immune profile to optimize outcomes in sepsis management
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