Should statistical analysis of bond-strength data include or exclude cohesive failures?

Objectives The aim was to investigate shear bond strengths and failure modes of four self-etch bonding agents to bovine dentin and enamel and to compare evaluation of data sets with or without exclusion of cohesive failure specimens. Methods Composite-cylinders were bonded perpendicularly to bovine dentin and enamel surfaces. Shear-strengths were measured 24 h post-bonding of: Scotchbond Universal® (SBU, 3 M), OptiBond™ XTR (OBXTR, Kerr), OptiBond™ universal (OBU, KaVo-Kerr) and Prime & Bond active® (PBA, Dentsply-Sirona). Analysis of overall data was made via a linear mixed-model. This was repeated after exclusion of specimens associated with cohesive failures. Results When both adhesive and cohesive failures were considered, OBU and OBXTR showed comparable dentin and enamel bond strengths, whereas lower strengths were found on enamel for SBU (p < 0.001) and PBA (p = 0.015). For OBXTR higher shear strengths were measured for specimens associated with cohesive failures. When cohesive failures were excluded, the majority of shear bond strengths of adhesive failure specimens were only slightly different from overall results. However, uniquely with OBXTR dramatically lower shear bond strengths were found for dentin substrate. Significance After exclusion of cases with cohesive failures OBXTR adhesive fell behind other materials in the sequence of average shear strengths. This did not reflect the actual performance of the material. Therefore, in statistical analysis we do not recommend exclusion of data based on a specific fracture mode

Alternatives to amalgam: Is pretreatment necessary for effective bonding to dentin?

Objective The aim of this study was to determine whether pretreatment of the dentin surface is beneficial or not by analysis of the bond strengths of four self-adhesive restoratives and four restoration materials where pretreatment of dentin was necessary. Methods Bovine incisors (n = 160) were ground flat on the labial surfaces to expose dentin using a grinder and silicon carbide (SiC) abrasive papers under running water. Between preparation and bonding procedures, the crowns were stored in Chloramine-T solution at 4 °C. Eight different restorative materials were studied: Activa BioActive (ABA), Cention Forte (CNF), Ceram.x Spectra ST (CXS), Riva self-cure (RSC), Equia Forte (EQF), Fuji II LC (FJI), Ketac Molar (KTM), Surefil one (SFO). Four materials required pretreatment of the dental hard tissue before placement, whereas the other four were self-adhesive (no pretreatment). The specimens were mounted vertically in plaster. A preload of 5 N was applied and the subsequent cross-head speed was 0.8 mm/min. Shear bond strengths (MPa) were calculated as the failure load divided by the bonding area. Failure modes were recorded as adhesive, cohesive or pretest. Data were statistically analyzed via ordinal regression for inference and Tukey’s method to adjust for multiple comparisons. All computations were done using R version 4.1.2 (R Core Team 2021). Results Smax (failure stress in MPa) of the combined groups with pretreatment were significantly higher than the self-adhesive materials. The highest frequency of pretest-failure was seen with FJI. Glass-ionomer cements without pretreatment were the only restoratives with pretest failures. Amongst materials without pretreatment, SFO had the highest bond strengths. Significance The further reduction of the placement steps for materials used as an amalgam alternative, namely the omission of pretreatment of the dentin, results in these self-adhesive materials having lower bond strengths than materials that require pretreatment of the dentin

Evaluation of Potential Reference Genes for Relative Quantification by RT-qPCR in Different Porcine Tissues Derived from Feeding Studies

Five potential reference genes for RT-qPCR application, namely histone H3, beta-actin, GAPDH, ubiquitin and 18S rRNA, were evaluated for normalization of gene expression in four selected tissues (liver, kidney, thyroid and abdominal fat). Tissues were derived from fattening pigs exposed to different amounts and type of dietary iodine. Two software applications (geNorm and NormFinder) were used to evaluate the stability of the potential reference genes. All studied genes displayed high expression stability but different stability patterns between the investigated tissues. The results suggest GAPDH and 18S rRNA as reference genes applicable in all tissues investigated. Beta-actin and histone H3 are suitable reference genes for all tissues investigated except fat. In contrast, ubiquitin should be excluded from use as a reference gene in the porcine tissues analyzed due to variations in expression levels, despite the good expression stability

Cytotoxicity of one-step dentin-bonding agents toward dental pulp and odontoblast-like cells

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73497/1/j.1365-2842.2008.01885.x.pd

Results of an international phosphorus digestibility ring test with broiler chickens

The objective of this ring test was to investigate the prececal phosphorus (P) digestibility of soybean meal (SBM) in broiler chickens using the trial protocol proposed by the World's Poultry Science Association. It was hypothesized that prececal P digestibility of SBM determined in the collaborating stations is similar. Three diets with different inclusion levels of SBM were mixed in a feed mill specialized in experimental diets and transported to 17 collaborating stations. Broiler chicks were raised on commercial starter diets according to station-specific management routine. Then they were fed the experimental diets for a minimum of 5 d before content of the posterior half of the ileum was collected. A minimum of 6 experimental replicates per diet was used in each station. All diets and digesta samples were analyzed in the same laboratory. Diet, station, and their interaction significantly affected (P &lt; 0.05) the prececal digestibility values of P and calcium of the diets. The prececal P digestibility of SBM was determined by linear regression and varied among stations from 19 to 51%, with significant differences among stations. In a subset of 4 stations, the prececal disappearance of myo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate)-P; InsP6-P) also was studied. The prececal InsP6-P disappearance correlated well with the prececal P digestibility. We hypothesized that factors influencing InsP6 hydrolysis were main contributors to the variation in prececal P digestibility among stations. These factors were probably related to the feeding and housing conditions (floor pens or cages) of the birds in the pre-experimental phase. Therefore, we suggest that the World's Poultry Science Association protocol for the determination of digestible P be should extended to the standardization of the pre-experimental period. We also suggest that comparisons of P digestibility measurements among studies are made only with great caution until the protocol is more refined

Molecular Toxicology of Substances Released from Resin–Based Dental Restorative Materials

Resin-based dental restorative materials are extensively used today in dentistry. However, significant concerns still remain regarding their biocompatibility. For this reason, significant scientific effort has been focused on the determination of the molecular toxicology of substances released by these biomaterials, using several tools for risk assessment, including exposure assessment, hazard identification and dose-response analysis. These studies have shown that substances released by these materials can cause significant cytotoxic and genotoxic effects, leading to irreversible disturbance of basic cellular functions. The aim of this article is to review current knowledge related to dental composites’ molecular toxicology and to give implications for possible improvements concerning their biocompatibility

Sustainable pig and poultry nutrition by improvement of nutrient utilisation A review : Nachhaltige Schweine- und Geflügelernährung durch Steigerung der Nährstoffnutzungseffizienz Eine Übersicht

Die ungeeignete Nutzung unserer natürlichen Ressourcen und der gleichzeitig weltweite steigende Konsum an tierischen Eiweiß durch die Weltbevölkerung stellt die Erzeugung von tierischen Lebensmitteln aus Schwein und Geflügel vor große Herausforderungen. Eine effiziente Transformation vom Futter zum tierischen Lebensmittel ist somit unausweichlich. Momentan stehen uns unterschiedliche „Werkzeuge“ zur Verfügung, wie Futtermittelzusatzstoffe oder eine technologische Futtermittelbehandlung, um die Effizienz und somit die Nachhaltigkeit bei der Erzeugung tierischer Lebensmittel verbessern zu können. Die genaue Kenntnis über die Wirkungsweise dieser „Werkzeuge“ stellt die Grundvoraussetzung zu deren erfolgreichen Einsatz bei der Ernährung von Schwein und Geflügel dar. Darüber hinaus ist deren Auswirkung auf die Nährstoffverdaulichkeit im Futtermittel und somit auch deren Energiegehalt von Bedeutung, um bedarfsgerechte Futterrationen berechnen zu können. Durch eine dem Leistungsniveau angepasste Nährstoffversorgung werden einerseits Unterversorgungen, welche zu gesundheitlichen Problemen führen können, vermieden, andererseits werden die Stickstoffemissionen so gering wie möglich gehalten. Durch den Einsatz der uns zur Verfügung stehenden Futtermittelzusatzstoffe beziehungsweise Futtermittelbehandlungen können regionale industrielle Nebenprodukte wie Weizenkleie, Trockenschlempe oder Rapsschrot in höheren Mengen dem Futter unserer monogastrischen Nutztiere zugesetzt werden. Die Nahrungskonkurrenz zum Menschen kann somit deutlich reduziert werden. Eine Verbesserung der Effizienz vom Futter zum tierischen Lebensmittel beinhaltet somit auch die Definition des Bergriffes „nachhaltig“. Eine Effizienzsteigerung bei der Produktion von tierischen Lebensmitteln aus Schwein und Geflügel spielt eine wichtige Rolle, um unsere erforderlichen natürlichen Ressourcen zur Ernährung von Schwein und Geflügel vernünftig und voraussehbar verfügbar zu machen. Derzeit scheint eine Kombination verschiedener „Werkzeuge“ wie Futtermittelzusatzstoffe und die technologische Futtermittelbehandlung die vielversprechendste Möglichkeit, eine nährstoffeffiziente und somit nachhaltige Schweine- und Geflügelproduktion sicher zu stellen.In the context of mismanagement of natural resources going with an increasing consumption of protein from animal origin through the world population, one major challenge for the future in animal nutrition is the improvement of its efficiency and hence sustainability. Up to now, a broad range of methods like feed additives or technological treatments have been available to improve the efficiency or the production of pig-derived and poultry-derived food and hence the sustainability in pig and poultry nutrition. Nevertheless, the exact knowledge of the mode of action of these tools is a prerequisite for their successful application. Furthermore, information concerning their impact on the nutrient availability of the different feedstuffs is of great importance, in order to formulate diets that cover the animals requirements. Diets covering the animals performance level ovoid undersupplies, which can lead to health problems on the on hand, on the other hand the emissions of nitrogen are kept as low as possible. As a result, the consumption of natural resources like grains can be considerably reduced and the substitution of regional by-products from the feed and food processing industry like wheat bran, dried distillers grains with solubles or rapeseed meal can be dramatically enhanced in diets for monogastric animals, thus contributing to more sustainable livestock production. By improving the efficiency of the production of animal-derived food, the term “sustainable remains highly significant. Increasing efficiency plays an important role in ensuring that the resources required for pig and poultry nutrition are foreseeably available. Currently, there is a combination of different tools like feed additives or technological feed treatments the most promising way of improving sustainability in pig and poultry production systems.(VLID)280658