Evaluation of Residual Monomers Eluted from Pediatric Dental Restorative Materials.

Unreacted monomers eluted from resin-based restorative materials have been considered a reason of local and systemic adverse reactions. This study was designed to determine the effect of finishing and polishing procedures on the elution of Bis-GMA, TEGDMA, UDMA, and HEMA monomers from compomer and bulk-fill composite resins. Bulk-fill composite (3M ESPE GmbH, Seefeld, Germany) and compomer (Dentsply DeTrey GmbH, Konstanz, Germany) specimens with 3 × 4 mm diameters were prepared. The specimens were randomly divided into two groups, and finishing-polishing procedures were applied only to the experimental groups. Release of residual monomers was analyzed by using High-Performance Liquid Chromatography (HPLC) after 24, 48, and 72 hours. Repeated measures ANOVA and Tukey post hoc tests were used for comparisons. Finishing and polishing procedures had a significant effect on reducing the quantity of UDMA release in the Filtek™ Bulk Fill composite and Bis-GMA, HEMA, and TEGDMA in the Dyract XP compomer (p < 0.05). The restorative materials investigated here are not chemically stable after polymerization, and concentrations of eluted monomers may reach critical toxicity levels even after one restoration placement. Finishing and polishing procedures are mandatory to reduce residual monomers.

Cytotoxic Evaluation and Determination of Organic and Inorganic Eluates from Restorative Materials.

Over the last years, diverse commercial resin-based composites have dominated as dental filling materials. The purpose of the present study was to determine organic and inorganic eluates from five restorative materials using GC/MS and ICP-OES and to compare the effect on cell survival of human gingival fibroblasts of a conventional and a bioactive resin. Five commercially available restorative materials were employed for this study: ActivaTM Bioactive Restorative, ENA HRi, Enamel plus HRi Biofunction, Fuji II LC Capsule, and Fuji IX Capsule. Disks that were polymerized with a curing LED light or left to set were immersed in: 1 mL methanol or artificial saliva for GC/MS analysis, 5mL deionized water for ICP-OES, and 5mL of culture medium for cell viability. Cell viability was investigated with a modified staining sulforhodamine B assay.The following organic substances were detected: ACP, BHT, BPA, 1,4-BDDMA, CQ, DBP, DMABEE, HEMA, MCE, MeHQ, MOPA, MS, TMPTMA, and TPSb and the ions silicon, aluminum, calcium, sodium, and barium. Activa Bioactive Restorative was found to be biocompatible. Elution of organic substances depended on material's composition, the nature of the solvent and the storage time. Ions' release depended on material's composition and storage time. The newly introduced bioactive restorative was found to be more biocompatible.

Discoloration of Resin Composites Induced by Coffee and Tomato Sauce and Subjected to Surface Polishing: An In Vitro Study.

BACKGROUND The purpose of this study is to evaluate and compare color stability of 3 resin based restorative materials when immersed into staining media at 0, 3, 30, 45, 60, and 75 days, and to assess the efficacy of surface polishing in reducing possible discoloration. MATERIAL AND METHODS Ninety composite discs were prepared in a custom-made mold (5 mm diameter and 2 mm thick) from 3 different light cured composites (Filtek™ Z250, Harmonize™, and G-aenial). Color differences of all specimens were measured by a spectrophotometer according to the CIE L*a*b* system. After baseline color measurements, 30 discs from each composite group were randomly divided into 3 subgroups of 10 specimens each. Subgroups (n=10) were immersed for 75 days into different staining solutions: coffee, tomato sauce, and distilled water (control). Solutions were changed every week and color measurements were repeated every 15 days. At day 75, color measurements of the specimens were performed before and after surface polishing with aluminum oxide discs. The experimental data were statistically evaluated using repeated measures one-way ANOVA test followed by Tukey's multiple pairwise comparison with a significance level of 5%. RESULTS Of the 3 composites, G-aenial reported the highest color change deviation when immersed into coffee (ΔE=8.674), and tomato sauce (ΔE=7.737) at day 75, followed by Harmonize that also exhibited a significant difference for coffee (ΔE=4.7) and tomato sauce (ΔE=3.8) when compared to distilled water. While Filtek™ Z250 did not show any significant difference between the 3 storage solutions (P>0.05). Only G-aenial had significant color change (P<0.05) after polishing with aluminum oxide discs for all tested samples, whereas Filtek™ Z250 and Harmonize presented no significant difference after surface polishing (P>0.05). CONCLUSIONS Under the tested experimental conditions, Filtek™ Z250, among the 3 resin-based composites, exhibited the highest color stability when subjected to coffee and tomato sauce as well. Whereas, G-aenial presented the highest color deviation when immersed in both staining media. Surface polishing effectively reduced coffee and tomato sauce discolorations for G-aenial's specimens and had no significant effect regarding Filtek™ Z250 and Harmonize.

Rapid and Easy Enrichment Strategy for Naturally Acetylated N Termini Based on LysN Digestion and Amine-Reactive Resin Capture.

Protein N-terminal acetylation (Nα-acetylation) is one of the most common modifications in both eukaryotes and prokaryotes. Although studies have shown that Nα-acetylation plays important roles in protein assembly, stability, and location, the physiological role has not been fully elucidated. Therefore, a robust and large-scale analytical method is important for a better understanding of Nα-acetylation. Here, an enrichment strategy was presented based on LysN digestion and amine-reactive resin capture to study naturally acetylated protein N termini. Since LysN protease cleaves at the amino-terminus of the lysine residue, all resulting peptides except naturally acetylated N-terminal peptides contain free amino groups and can be removed by coupling with AminoLink Resin. Therefore, the naturally acetylated N-terminal peptides were left in solution and enriched for further liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The method was very simple and fast, which contained no additional chemical derivatization except protein reduction and alkylation necessarily needed in bottom-up proteomics. It could be used to study acetylated N termini from complex biological samples without bias toward different peptides with various physicochemical properties. The enrichment specificity was above 99% when it was applied in HeLa cell lysates. Neo-N termini generated by endogenous degradation could be directly distinguished without the use of stable-isotope labeling because no chemical derivatization was introduced in this method. Furthermore, this method was highly complementary to the traditional analytical methods for protein N termini based on trypsin only with ArgC-like activity. Therefore, the described method was beneficial to naturally acetylated protein N termini profiling.

Release and migration of cyclic polyester oligomers from bisphenol A non-intent polyester-phenol-coatings into food simulants and infant food - a comprehensive study.

Coatings for cans or closures are essential to protect the metal from corrosion and the food from migration of hazardous metal ions. Since coatings are no inert materials, they can release substances of potential health concern into food. In the present study, a comprehensive analysis is presented for a complex two-layered polyester-phenol-coating commercially used for metal closures of complementary infant food in sterilised glass jars. Focussed on the identity and migration of cyclic polyester oligomers as a kind of predictable non-intentionally added substances, polyester resin raw materials (n = 3) as well as individual coating layers (n = 3) were characterised by several analytical strategies (size exclusion chromatography, high-performance liquid chromatography mass spectrometry, diode array detection, charged aerosol detection, monomer determination after alkaline hydrolysis, overall migrate). The main polyester monomers were terephthalic acid, isophthalic acid, trimellitic acid, ethylene glycol, diethylene glycol, neopentylglycol, 2-methyl-1,3-propanediol, 1,4-butanediol and tricyclodecanedimethanol. The coatings were extracted with solvents acetonitrile and ethanol (24 h, 60°C), food simulants 50% ethanol, 20% ethanol and water (1 h, 121°C) as well as homemade and commercial baby food (1 h, 121°C). The released total polyester content determined by alkaline hydrolysis ranged from 288 µg/dm2 (water, 1 h, 121°C) to 6154 µg/dm2 (acetonitrile, 24 h, 60°C). However, individual cyclic oligomers, mainly dimers, were released from the coating to up to about 140 µg/dm2. Migration into infant food was best represented by the food simulants water (up to 1% fat) and 20% ethanol (up to 5% fat). Cyclic polyester oligomers are classified as Cramer III substances by the threshold of toxicological concern concept associated to an exposure threshold of 1.5 µg/kg body weight per day. Exposure to cyclic polyester oligomers might be a potential concern for highly exposed infants.

Formaldehyde Release From Clothing and Upholstery Fabrics Using the Chromotropic Acid Method.

BACKGROUND: Formaldehyde resins may be used in textiles. OBJECTIVE: The aim of the study was to investigate the presence of formaldehyde in textiles using the chromotropic acid method. METHOD: Clothing scraps (from local department store tailors, n = 77) and upholstery fabric cuttings (from a furniture reupholstery store, n = 22) were collected. Each fabric was cut into a 1-cm square and tested using the chromotropic acid method. Samples were retested in a systematic fashion (every 10th sample) to assess reproducibility. RESULTS: All 99 clothing and upholstery fabrics tested negative for formaldehyde release. CONCLUSIONS: Our study suggests that textile manufactures may be using nonformaldehyde resins for durable press finishing in clothing likely to be tailored as well as fabrics used for furniture reupholstery. Additional studies involving other metropolitan areas and a variety of fabrics are needed to confirm these findings.

Comparison of microtensile bond strength and resin-dentin interfaces of two self-adhesive flowable composite resins by using different universal adhesives: Scanning electron microscope study.

The aim of this in-vitro study was to evaluate microtensile bond strength (µTBS) of two different self-adhesive composites (SACs) on the permanent dentin by applying five different universal adhesive systems. In this study, two different SACs [Vertise Flow (VF), Fusio Liquid Dentin (FLD)] and five different bonding systems [Clearfil Universal Bond Quick (CUB), Single Bond Universal (SBU), All Bond Universal (ABU), Prime Bond Universal (PBU), Futurabond U (FBU)] were used. A total of 22 groups were created in which SACs were applied without adhesive and with five different universal bonding agents in total-etch (TE) and self-etch (SE) modes. Two hundred and forty test sticks were obtained using 48 healthy human molar teeth in total with groups having 10 samples each. The µTBS test was applied to each sample in the Universal test device and the data obtained were analyzed statistically by variance analysis and Tukey HSD test. In addition, the resin-dentin interface and fractures modes in the groups were examined by SEM. Upon examining the µTBS results, the highest values were seen in the use of SBU adhesive in TE mode in VF group, while the lowest values were seen in the FLD control group. The difference between the control and experimental groups was found statistically significant (p < .05). Upon comparing the control groups with each other, it was seen that VF group had higher µTBS values than FLD group and the difference between the groups was found statistically significant (p < .05). The µTBS results and SEM images of the study showed that the use of SACs with universal adhesive systems provides a more effective bond strength.

Dynamic analysis of bulk-fill composites: Effect of food-simulating liquids.

This study investigated the effect of food simulating liquids on visco-elastic properties of bulk-fill restoratives using dynamic mechanical analysis. One conventional composite (Filtek Z350 [FZ]), two bulk-fill composites (Filtek Bulk-fill [FB] and Tetric N Ceram [TN]) and a bulk-fill giomer (Beautifil-Bulk Restorative [BB]) were evaluated. Specimens (12 × 2 × 2mm) were fabricated using customized stainless steel molds. The specimens were light-cured, removed from their molds, finished, measured and randomly divided into six groups. The groups (n = 10) were conditioned in the following mediums for 7 days at 37°C: air (control), artificial saliva (SAGF), distilled water, 0.02N citric acid, heptane, 50% ethanol-water solution. Specimens were assessed using dynamic mechanical testing in flexural three-point bending mode and their respective mediums at 37°C and a frequency range of 0.1-10Hz. The distance between the supports were fixed at 10mm and an axial load of 5N was employed. Data for elastic modulus, viscous modulus and loss tangent were subjected to ANOVA/Tukey's tests at significance level p < 0.05. Significant differences in visco-elastic properties were observed between materials and mediums. Apart from bulk-fill giomer, elastic modulus was the highest after conditioning in heptane. No apparent trends were noted for viscous modulus. Generally, loss tangent was the highest after conditioning in ethanol. The effect of food-simulating liquids on the visco-elastic properties of bulk-fill composites was material and medium dependent.

Evaluación de la superficie del esmalte luego de la descementación de brackets metálicos. Revisión sistemática / Enamel Surface Assessment after Metallic Bracket Debonding. A Systematic Review

Antecedentes: A través del tiempo se han propuesto diferentes técnicas para realizar la remoción del adhesivo y resina remanentes luego de retirar los brackets, pero no existe un consenso entre los diferentes autores. Objetivo: el propósito de esta revisión sistemática fue identificar cuál es la técnica más adecuada para evitar injuria al esmalte durante la remoción de la resina remanente después de retirados los brackets. Métodos: Esta revisión sistemática se basó en los lincamientos de PRISMA, Para recolectar la evidencia publicada se realizó una búsqueda electrónica en diferentes bases de datos. Resultados: Se encontraron 8 artículos con una evidencia media (> de 9) los cuales fueron considerados en esta revisión sistemática. Al parecer la remoción de resina y adhesivo remanentes con ultrasonido, fresa de carburo de tungsteno de alta velocidad y piedras blancas generan la mayor pérdida de esmalte, mientras que 6 artículos proponen la fresa de tungsteno de baja velocidad como la mejor técnica. Conclusiones: Se requieren estudios aleatorizados, con grupo control, doble-ciego y una técnica de análisis del esmalte estandarizada para poder generar un nivel de evidencia alto y dar recomendaciones más acertadas para el clínico.

Background: Over time different techniques have been proposed for the removal of the remaining adhesive and resin after the removal of brackets, but there is no consensus among authors. Objective: Evaluate the most appropriate technique to prevent injury to the enamel during the removal of the remaining resin after the brackets are removed. Methods: This systematic review is based on the guidelines of PRISMA, to collect the published evidence there was a various electronic databases search. Results: There were only 8 items with medium evidence (> 9) which were considered in this systematic review. Apparently removing remaining adhesive resin with ultrasound, tungsten carbide cutter high speed and white stones generate the greatest loss of enamel, while 6 articles propose the tungsten bur at low speed as the best technique. Conclusions: Randomized studies with control group, double-blind and a standardized technique of enamel analysis are required to generate a high level of evidence and give more accurate recommendations for clinicians.

Evaluation of resin infiltration using quantitative light-induced fluorescence technology.

OBJECTIVES: To determine whether quantitative light-induced fluorescence (QLF) technology can be used to classify the colour of teeth specimens before and after resin infiltration (RI) treatment, and calculate the correlation between the ΔF value and colour difference (ΔE) in fluorescence images of the specimens obtained using a QLF-digital (QLF-D) device. METHODS: Sixty sound bovine permanent teeth specimens were immersed in demineralized solution. Two exposed windows were formed in each specimen, and RI treatment was applied to one of them. The ΔE values were obtained for the differences between a sound tooth surface (SS), an early dental caries surface (ECS) and an ECS treated with RI (RS) in white-light and fluorescence images obtained using QLF-D, respectively. The ΔF value was obtained from fluorescence images using dedicated software for QLF-D. The mean differences between the ΔE values obtained from the white-light and fluorescence images were analyzed by paired t-test. Pearson correlation analysis and Bland-Altman plots were applied to the differences between the ΔF value for ECS (ΔFSS-ECS) and the ΔE value between SS and ECS (ΔESS-ECS), and between the ΔF value for RS (ΔFSS-RS) and the ΔE value between SS and RS (ΔESS-RS) in fluorescence images. RESULTS: The ΔE values obtained from fluorescence images were three times higher than the ΔE values obtained from white-light images (p<0.001). Significant correlations were confirmed between ΔESS-ECS and ΔFSS-ECS (r=-0.492, p<0.001) and between ΔESS-RS and ΔFSS-RS (r=-0.661, p<0.001). CONCLUSION: QLF technology can be used to confirm the presence of RI in teeth.

Highly Sensitive Detection of Melamine Using a One-Step Sample Treatment Combined with a Portable Ag Nanostructure Array SERS Sensor.

There is an urgent need for rapid and reliable methods able to detect melamine in animal feed. In this study, a quick, simple, and sensitive method for the determination of melamine content in animal feed was developed using surface-enhanced Raman spectroscopy on fabricated Ag nanorod (AgNR) array substrates with a one-step sample extraction procedure. The AgNR array substrates washed by HNO3 solvent (10-7 M) and methanol and showed the good stability within 6 months. The Raman shift at △ν = 682 cm-1 was used as the characteristic melamine peak in the calculations. Sufficient linearity was obtained in the 2-200 µg·g-1 range (R2 = 0.926). The limits of detection and quantification were 0.9 and 2 µg·g-1, respectively. The recovery rates were 89.7-93.3%, with coefficients of variation below 2.02%. The method showed good accuracy compared with the tradition GC-MS analysis. This new protocol only need 2 min to fininsh the detection which could be developed for rapid onsite screening of melamine contamination in quality control and market surveillance applications.

[Endodontic filling with gutta-percha- requirements, formation and characteristics]. / Obturation du canal radiculaire à la gutta-percha – exigences, composition et propriétés.

Gutta-percha is a tough plastic substance from the latex of several Malaysian trees of the sapodilla family that resembles rubber but contains more resin. It is especially used as insulation and in dentistry. Gutta-percha endodontic filling points were found to contain approximately 20% gutta-percha (matrix), 66% zinc oxide (filler), 11% heavy metal sulphates (radiopacifier), and 3% waxes and/or resins (plasticiser). The mechanical properties were indicative of a partially crystalline viscoelastic polymeric material.

A Continuous Procedure Based on Column Chromatography to Purify Anthocyanins from Schisandra chinensis by a Macroporous Resin plus Gel Filtration Chromatography.

In our previous study, as natural food colorants and antioxidants, the color and content stabilities of Schisandra chinensis (S. chinensis) anthocyanins were investigated. In this work, the purification process parameters of S. chinensis anthocyanins using a macroporous resin and gel filtration chromatography were evaluated. The optimized parameters of static adsorption and desorption were as follows. The selected resin is HPD-300 (nonpolar copolymer styrene type resin), and the anthocyanins adsorption saturation capacity of HPD-300 resin was 0.475 mg/g dry resin. Adsorption time was 4 h, and 0.517 mg/mL of S. chinensis anthocyanins was adsorbed on the resin column with a flow rate of 39 mL/h (3 BV/h). After adsorption, the anthocyanins were completely desorpted with 2.5 BV of 90% (v/v) ethanol solution, and the desorption flow rate was 13 mL/h (1 BV/h). After purification by dynamic adsorption and desorption, the anthocyanins content in the effluent increased from 47.6 mg/g to 128.4 mg/g, the purity of anthocyanins increased six-fold from 5.08% to 30.43%, and the anthocyanins recovery was 96.5%. The major constituent of S. chinensis anthocyanins was isolated with Bio-Gel P2 gel filtration chromatography, and it was detected by liquid chromatography electrospray ionisation tandem mass spectrometry (LC-ESI-MS) as cyanidin-3-O-xylosylrutinoside. Moreover, the antioxidant activities of S. chinensis anthocyanins were investigated. After purification using the HPD-300 resin, the antioxidant activities of anthocyanins were increased 1.2-fold (FRAP) and 1.7-fold (ABTS).

Estabilidad marginal de una resina condensable versus resina monoincremental activada sónicamente en restauraciones clase II: Estudio in vitro / Marginal stability of a condensable resin versus a bulk-fill resin with sonic activation in class II restorations: An in vitro study

Introducción: Recientemente se han introducido las resinas bulk-fill, las cuales pueden ser utilizadas con técnica monoincremental, disminuyendo el tiempo clínico y ofreciendo una técnica menos sensible. El objetivo de este estudio es evaluar la estabilidad marginal de una resina compuesta condensable, utilizando técnica incremental oblicua versus una resina monoincremental con activación sónica en restauraciones clase II. Materiales y método: A 16 terceros molares sanos se les realizó dos preparaciones cavitarias clase II. Las dimensiones de las preparaciones fueron estandarizadas: 3 mm de ancho vestibulolingual, 2 mm de profundidad y 1,5 mm en sentido mesiodistal para el cajón oclusal, y 3 mm de ancho vestibulolingual, 4 mm de profundidad y 1,5 mm en sentido mesiodistal para el cajón proximal, determinándose al azar restaurar una preparación con resina condensable FiltekTM P60 (3M(R) ESPE-USA) utilizando técnica incremental, y la segunda preparación con resina SonicFillTM (Kerr-USA) con técnica monoincremental y activación sónica. Las muestras se termociclaron en azul de metileno al 1%, se cortaron en sentido mesiodistal y analizaron mediante microscopio óptico. Se cuantificó el grado de penetración del agente infiltrador en el margen cavosuperficial oclusal y gingival de ambas resinas. Se realizó un test exacto de Fisher y posterior U de Mann-Whitney. Resultados: La profundidad de infiltración del borde cavosuperficial gingival fue significativamente menor para FiltekTM P60 comparado con SonicFillTM (p= 0,028). Discusión: Ambas técnicas presentaron valores similares de estabilidad marginal en el borde cavosuperficial oclusal, sin embargo la resinas FiltekTM P60 presenta una mayor estabilidad marginal en el borde cavosuperficial gingival (AU)

Introduction: Recently, bulk-fill resin shave been introduced, which can be used with a mono-incremental technique, shortening clinical time and offering a less sensitive technique. The purpose of this study was to evaluate the marginal stability of condensable composite resins by using incremental technique versus a bulkfill resin with sonic activation. Material and method: Two Black’s class II cavities preparations were performed on 16 healthy third molars. The overall dimensions and depth of cavities were standardized as follows: 3 mm wide, 2 mm deep and 1,5 mm of mesiodistal lenght at the occlusal box, and 3 mm wide, 4 mm deep and 1,5 mm of mesiodistal length at the proximal box. It was randomly determined to restore a preparation with condensable resin FiltekTM P60 (3M(R) ESPE-USA) using oblique incremental technique, while these cond preparation used SonicFillTM resin (Kerr- USA) with mono-incremental technique and sonic activation. These were thermocycled in methylene blue 1%, then cut in mesio-distal sense and analysed by optical microscope. The degree of penetration of the infiltrator agent in the oclusal cavosurface margin and gingival wall of both resins was measured. Fisher’s exact test and a subsequent Mann-Whitney U test were performed. Results: The amount of infiltration in gingival cavosurface margin was significantly lower for Filtek™ P60 compared with SonicFillTM (p= 0.028). Discussion: Both techniques presented similar values of marginal stability in the oclusal cavosurface margin, however, resinFiltekTM P60 has greater stability in the gingival cavosurface margin (AU)

Principal component analysis of molecularly based signals from infant formula contaminations using LC-MS and NMR in foodomics.

BACKGROUND: The challenge in developing analytical assessment of unexpected excess contaminations in infant formula has been the most significant project to address the widespread issue of food safety and security. Foodomics based on metabolomics techniques provides powerful tools for the detection of tampering cases with intentional contaminations. However, the safety and risk assessments of infant formula to reveal not only the targeted presence of toxic chemicals, but also molecular changes involving unexpected contaminations, have not been reported. In this study, a huge amount of raw molecularly based signals from infant formula was analysed using reversed phase and hydrophilic interaction chromatography with time-of-flight MS (LC-MS) and (1) H nuclear magnetic resonance (NMR) and then processed by a principal component analysis (PCA). RESULTS: PCA plots visualised signature trends in the complex signal-data batches from each excess contamination of detectable chemicals by LC-MS and NMR. These trends in the different batches from a portion of excess chemical contaminations such as pesticides, melamine and heavy metals and out-of-date products can be visualised from spectrally discriminated infant formula samples. CONCLUSION: PCA plots provide possible attempts to maximise the covariance between the stable lot-to-lot uniformity and excess exogenous contaminations and/or degradation to discriminate against the molecularly based signals from infant formulas. © 2015 Society of Chemical Industry.

Effect of resin content and substrate on the emission of BTEX and carbonyls from low-VOC water-based wall paint.

The primary aim of this work is to explore the effect of resin content and the effect of substrate on the emission of benzene, toluene, ethylbenzene, and xylene (BTEX) and carbonyls from low-VOC water-based wall paint. Four low-volatile organic compound (VOC) paints include paints A (20% acrylic), B (30% acrylic), C (20% polyvinyl acetate), and D (30% polyvinyl acetate) were painted on stainless steel specimen for the study of resin effect. Green calcium silicate, green cement, and stainless steel were painted with paints A and C for the study of substrate effect. Concentrations of the VOCs in the chamber decreased with the elapsed time. Both resin type and resin quantity in paint had effects on VOC emissions. Paints with acrylic resin emitted less BTEX and carbonyls than paints with polyvinyl acetate resin. However, the effects of resin quantity varied with VOCs. Porous substrates were observed to interact more strongly with paints than inert substrates. Both green calcium silicate and green cement substrates have strong power of adsorption of VOCs from wall paints, namely toluene, formaldehyde, acetaldehyde, 2-butanone, methacrolein, butyraldehyde, and benzaldehyde. Some compounds like toluene, formaldehyde, and butyaldehyde were desorbed very slowly from green calcium silicate and green cement substrates.

Influência do agente cimentante e desajuste interno na adaptação marginal de coroas em resina nanocerâmica / Influence of the cement agent and internal mismatch in the marginal adaptation of nanoceramic resins crowns

A adaptação marginal é um dos requisitos fundamentais para a longevidade e o sucesso das restaurações. O objetivo desse estudo foi avaliar a influência do desajuste interno associado à diferentes agentes cimentantes na desadaptação marginal de coroas em resina nanocerâmica (Lava Ultimate 3M ESPE) confeccionadas pelo sistema CAD-CAM. A partir do escaneamento de um preparo de coroa total em um pré-molar, foram obtidos 36 modelos em metal. Esses foram divididos em seis grupos de acordo com o desajuste interno (70 µm ou 100 µm) e o cimento (Fosfato de zinco- SS White, Cimento de ionômero de vidro- Ketac Cem 3M/ESPE e Cimento resinoso- Relyx Ultimate 3M/ESPE). Após escaneamento de todos os modelos as coroas foram confeccionadas a partir da fresagem de blocos de resina nanocerâmica (Lava Ultimate 3M/ESPE). Com auxílio de microscópio óptico comparador (40X) foram medidas as desadaptações marginais prévia e posteriormente à cimentação, sendo considerados 8 pontos ao longo do término em todas as faces do corpo de prova. Os valores obtidos após serem submetidos aos testes two-way anova e teste t, demonstraram que as coroas confeccionadas com desajuste interno de 70 µm apresentam desadaptação marginal inferior estatisticamente significante às coroas com desajuste interno de 100 µm. Para o desajuste interno de 70 µm o grupo do cimento fosfato de zinco apresentou o menor gap marginal, sendo que este valor não foi estatisticamente diferente em relação ao grupo do Ketac Cem. Ainda com esse desajuste, o grupo do Ketac Cem não apresentou diferença estatística significante em relação ao grupo do Relyx Ultimate, no entanto esse último promoveu "gap" marginal estatisticamente maior em relação ao grupo do cimento fosfato de zinco. Para o desajuste interno de 100 µm não houve diferença estatisticamente significante no "gap" marginal entre os três cimentos avaliados. O presente estudo demonstrou através da metodologia utilizada, que a menor desadaptação marginal observada nas restaurações de Lava Ultimate, foi proveniente do desajuste interno de 70 µm. Neste grupo os cimentos de fosfato de zinco e de ionômero de vidro demonstraram melhor comportamento comparado ao cimento resinoso, embora o cimento de ionômero de vidro numericamente, mas não estatisticamente tenha apresentado resultado inferior ao do fosfato de zinco

The marginal adaptation is one of the basic requirements for the longevity and success of restorations. The aim of this study was to evaluate the influence of the internal imbalances associated with different luting agents on marginal leakage of crowns Nanoceramic resin ( Lava Ultimate 3M ESPE) made by CAD-CAM system. From the scanning of a full crown preparation in a pre molar were obtained 36 metal models. These were divided into six groups according to the internal imbalances ( 70 or 100 micrometres) and cement (SS White Zinc phosphate, glass ionomer cemet Ketac Cem 3M/ Espe and resinous cement Relyx Ultimate 3M / Espe). After scanning all models crowns were made from milling Nanoceramic resin blocks (Lava Ultimate 3M / Espe). With the aid of optical comparator microscope (40X) were measured prior marginal mismatches and after the cementation, being considered 8 points along the end in all specimen faces. The values were submitted to ANOVA two-way test and t test. Results showded that crowns made with internal imbalances of 70 uM show statistically significant lower marginal leakage to the crows with internal imbalances of 100 micrometres. For the internal imbalances 70 uM zinc phosphate cement group showed the lowest "gap" marginal, and this figure does not show a statistically significant difference compared to Ketac Cem gropu. Even with this misfit, Ketac Cem group showed no statistically significant difference in relation to Relyx Ultimate group, though the latter showed a statistically significant difference compared to zinc phosphate cement group. For the internal imbalances of 100 micrometres there was no statistically significant difference in the "gap" marginal among the three cements. This study demostrated through the methodology used, the lower marginal leakage oberved in Lava Ultimate restorations, was from the inner misfit 70 micrometers...

Phytophthora austrocedri Elicitates Changes in Diterpene Profile of Austrocedrus chilensis.

The populations of the Andean Cupressaceae Austrocedrus chilensis have been severely affected by a disease caused by the phytopathogenic fungus Phytophthora austrocedri. A study was undertaken to disclose changes in the resin composition of P. austrocedri-infected individuals, including naturally infected and artificially inoculated trees, compared with healthy A. chilensis trees. GC-MS and (1)H-NMR studies showed a clear differentiation among healthy and infected resins, with the diterpene isopimara-8(9),15-dien-19-ol as a relevant constituent in resins from infected trees. The effect of resin fractions from P. austrocedri infected trees on the pathogen was assessed by measuring the mycelial growth in agar plates. The most active fractions from resin obtained from infected trees inhibited fungal growth by nearly 50% at 1 mg/dish (35.37 µg/cm(2)). The main constituent in the active fractions were 18-hydroxymanool and the aldehyde torulosal. Both compounds are oxidation products of manool and can be a chemical response of the tree to the pathogen or be formed from the pathogen as a biotransformation product of manool by microbial oxidation. While the diterpene profiles from A. chilensis tree resins can easily differentiate healthy and P. austrocedri infected individuals, the possible conversion of manool to the antifungal derivatives 4 and 6 by the microorganism remains to be established.

Microplastic resin pellets on an urban tropical beach in Colombia.

Microplastics are a problem in oceans worldwide. The current situation in Latin America is not well known. This paper reports, for the first time, the presence of microplastics on an urban Caribbean beach in Cartagena, Colombia. Pellet samples were collected from a tourist beach over a 5-month period covering both dry and rainy seasons. Pellets were classified by color and their surface analyzed by stereomicroscopy, and some were characterized by infrared spectroscopy. The most abundant pellets were white, presenting virgin surfaces, with few signs of oxidation. This is congruent with a short residence time in the marine environment and primary sources possibly located nearby. The frequency of white pellets did not change with sampling period. Surface features identified in the pellets included cracks, material loss, erosion, adhesion, granulation, color change, and glazed surfaces. Reticulated granular pellets exhibited the greatest degradation, easily generating submicroplastics. Sample composition was mostly polyethylene, followed by polypropylene. This pollution problem must be addressed by responsible authorities to avoid pellet deposition in oceans and on beaches around the world.

Determination of polyoxymethylene (POM)--water partition coefficients for oxy-PAHs and PAHs.

Oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs) are a class of ubiquitously occurring pollutants of which little is known. They can be co-emitted with PAHs or formed from PAHs in the environment. The environmental fate and risk of oxy-PAHs are difficult to assess due to a lack of methods to quantify their pore water concentrations. One sampler that can be used to determine freely dissolved concentrations of organic contaminants is polyoxymethylene (POM). In this study, POM - water partition coefficients (KPOM) were determined for 11 oxy-PAHs. KPOM values of 8 PAHs with similar hydrophobicities as the oxy-PAHs were determined for comparison. Results showed that logKPOM values ranged from 2.64 to 4.82 for the PAHs (2-4 rings), similar to previously determined values. LogKPOM values for investigated oxy-PAHs ranged from 0.96 to 5.36. The addition of carbonylic oxygen on a parent PAH generally lowered KPOM by 0.5 to 1.0 log units, which is attributable to the presence of carbonylic oxygens increasing water solubility. The KPOM values presented here will facilitate simultaneous assessments of freely dissolved water concentrations of oxy-PAHs and PAHs in environmental media.