In vitro comparison of marginal infiltration between a conventional resin and a bulk-fill resin, in the relocation of cervical margins technique / Comparación in vitro de la infiltración marginal entre una resina convencional y una resina bulk-fill, en la técnica de reubicación de márgenes cervicales

Introduction: Proximal lesions that exceed the cement enamel limit (ACE) under the gingival margin complicate impressions and the adhesive technique. Compare the magnitude of micro infiltration between conventional resin and bulk fill resin in the cervical margin relocation technique. Materials and Methods: 48 samples of human teeth re-ceived two preparations: occluso-mesial (OM) and occluso-distal (OD) under LAC; first they received the cervical margin relocation technique (RMC) with bulk fill and conventional resin; then restored with semi-direct resinous inlays. Sample analysis: immersion in 50% colloidal silver nitrate solution, 24 hours, 37°C and cut mesiodistally. Observed under a stereoscopic magnifying glass to assess dye penetration and digitally photographed, analyzed with "Image J" software. Results: Sample of 96 cavities in two groups of 48 units; control group restored with conventional resin with incremental technique and study group restored with bulk fill resin, mono-incremental technique. Probabilistic sampling. No statistically significant diffe-rences in percentage of microinfiltrated area between Filtek™ Z250™ and Filtek™ Bulk Fill™ (p-value= 0.68). Discussion: Various studies show that the presence of marginal microinfiltration exist independent of: restorative technique, consistency, adhesive mechanism and polyme-rization technique. The research carried out is no exception, observing a similar degree for both systems. Conclusions: Results allow us to conclude that conventi-onal resin and bulk fill resin did not show significant differences in microleakage percentages for the RMC technique. Outside the study framework, bulk fill resins would have comparative advantages; better behavior against light in depths greater than 2 mm, less sensitivity to the "C" factor, and less clinical time.

Introducción: Las lesiones proximales que superan el límite cemento esmalte (ACE) por debajo del margen gingival complican las impresiones y la técnica adhesiva. Comparar la magnitud de la microinfiltración entre la resina convencional y la resina de relleno en la técnica de reubicación del margen cervical. Materiales y Métodos: 48 muestras de dientes humanos recibieron dos preparaciones: ocluso-mesial (OM) y ocluso-distal (OD) bajo LAC, primero recibieron la técnica de reubicación del margen cervical (RMC) con relleno en bloque y resina convencional; luego restaurado con incrustaciones resinosas semidirectas. Análisis de la muestra: inmersión en solución de nitrato de plata coloidal al 50%, 24 horas, 37°C y corte mesiodistal. Observado bajo una lupa estereoscópica para evaluar la penetración del tinte y fotografiado digitalmente, analizado con el software "Image J". Resultados: Muestra de 96 cavidades en dos grupos de 48 unidades; grupo control restaurado con resina convencional con técnica incremental y grupo estudio restaurado con resina bulk fill, técnica mono-incremental. Muestreo probabilístico. No hubo diferencias estadísticamente significativas en el porcentaje de área microinfiltrada entre Filtek™ Z250™ y Filtek™ Bulk Fill™ (p-value = 0,68) Discusión: Diversos estudios evidencian presencia de microinfiltración marginal, independiente de técnica restauradora, consistencia, mecanismo adhesivo y técnica polimerizadora. La investigación realizada no es excepción, observándose grado similar para ambos sistemas. Conclusiones: Los resultados permiten concluir que resina convencional y resina bulk fill no presentaron diferencias significativas en porcentajes de microinfiltración para técnica RMC. Fuera del marco del estudio, resinas bulk fill tendrían ventajas comparativas; mejor comportamiento frente a la luz en profundidades superiores a 2 mm, menor sensibilidad al factor "C", y menor tiempo clínico.

Analysis of protein composition of H5N1 influenza virus inactivated vaccine(MDCK cells) bulks / 中国生物制品学杂志

@#ObjectiveTo analyze the protein components in the bulks of H5N1 inactivated influenza virus vaccine(MDCK cells),providing experimental basis for the improvement of the quality control method and the development of the vaccine.MethodsThe H5N1 influenza virus strain was inoculated into MDCK cells. After culturing the virus for 48 h,the virus liquid was harvested,and the original liquid sample was obtained by clarification and ultrafiltration concentration,β-propiolactone inactivation,and two-step chromatography purification with Capto Q and Sephorase 4FF. Morphology of virus particles in the sample was analyzed by transmission electron microscopy,while hemagglutinin identification of the virus bulk by single radial immunodiffusion(SRID)assay,purity by high performance liquid chromatography,and protein electrophoresis by gradient SDS-PAGE. The protein components contained in the samples were analyzed by liquid chromatography-mass spectrometry(LC/MS)combined with secondary mass spectrometry sequence determination of the recovered protein polypeptides.ResultsSpherical H5N1 influenza virus particles of 80 ～ 120 nm were observed under transmission electron microscope,showing the typical shape of influenza virus. The identification test showed that the antigenicity of the virus bulks was consistent with the virus strain. The gradient SDS-PAGE analysis showed that the virus bulk had two bands. LC/MS mass spectrometry analysis showed that H5N1 influenza virus protein was the main component in the bulk samples,including NP,M1,HA,NA and other proteins of H5N1 influenza virus.ConclusionThe protein composition of the bulk during the preparation of H5N1 influenza virus inactivated vaccine was analyzed,which provided a reference for the development and quality control of this type of vaccine.

Development and validation of size exclusion column-high performance liquid chromatography for purity determination of bulk material of freeze-dried rabies vaccine for human use / 中国生物制品学杂志

@#Objective To develop and validate size exclusion column-high performance liquid chromatography(SEC-HPLC)for determination of the purity of bulk material of freeze-dried rabies vaccine for human use.Methods Chromatography column TSK-gel G6000PW_(XL)(7.8 mm × 30 cm,13 μm)was used for the determination(column temperature 30 ℃)with mobile phase of 0.1 mol/L PB buffer(pH 7.8)at a flow rate of 0.5 mL/min.The detection wavelength was 280 nm and injection volume was 20 μL.The method was validated for system suitability,specificity,precision and durability and determined for detection limit and quantitation limit,which was applied to analyze bulk material purity of freeze-dried rabies vaccine for human use of 3 batches of Vero cells and 1 batch of human diploid cells.Results The resolution of target protein spectrum peak of bulk material of reference sample and freeze-dried rabies vaccine for human use prepared with two substrates was more than 1.5 with a tailing factor less than 1.5;The blank solvent showed no absorption peak at the position of target protein peak with no interference in the determination;The RSDs of retention time and peak area in precision verification were both less than 2.0%;The quantitative limit was 10 μg/mL,and the detection limit was 4 μg/mL;The reference sample was injected three times continuously at three different detection wavelengths of 278,280 and 282 nm,and the RSDs of retention time and peak area were also less than 2.0%.The purity of 4 batches of freeze-dried rabies vaccine bulk material for human use was all more than 97%.Conclusion The developed SEC-HPLC for determination of the purity of freeze-dried rabies vaccine bulk material for human use showed good specificity,precision and durability,which provided a reliable method for the quality control of human rabies vaccine.

Analysis of Tumor Immune Microenvironment Based on Bulk RNA-sequencing Data and Its Application / 肿瘤防治研究

Cancer immunotherapy is one of the most promising biological therapies. The dynamic changes of the immune microenvironment of heterogeneous tumors are critical factors in determining the interaction and therapeutic efficacy between tumor and immune microenvironment. Therefore, quantitative analysis of its constituent cells, related genes, and phenotypes in real time is of great importance. The methods used to analyze tumor immune microenvironment include immunohistochemistry, flow cytometry and so on. With the development of next-generation sequencing technology, transcriptome RNA sequencing data analysis has become one of the important methods to determine the composition of tumor immune microenvironment. This article focuses on the common methods of bulk RNA sequencing data analysis and related research progress.

Clinical study of different composite resin systems in Class I cavities (an 18-month randomized clinical trial) / Estudo clínico de diferentes sistemas de resina composta em cavidades de Classe I (um ensaio clínico randomizado de 18 meses)

Objective: this double-blind randomized clinical trial evaluate the clinical performance of Thermo-Viscous Bulk Fill composite, Self-Adhesive Flowable composite, and Filtek Bulk Fill Composites restorations in Class I cavities over a period of 18 months. Material and Methods: twenty individuals between the ages of 30 and 45 participated in this research. Each patient should have at least three occlusal Class I carious lesions on their molars. They were dispersed at random, with n=20 teeth representing each tested material. Group I (Futurabond M+ and VisCalor Bulk Fill which heated in a viscolar dispenser at 68 °C for 30s and placed in a 4 mm thickness), Group II (Fusio Liquid Dentin self-adhesive composite which put in a thin layer (1mm increment)), and Group III (Single Bond Universal and Filtek Bulk Fill Posterior composite which applied in 4 mm thickness without heating). Using (USPHS) criteria, all restorations were assessed clinically at baseline, 6 months, 12 months, and 18 months. Using an inverse replica, the marginal seal of the investigated restorations was further evaluated under SEM. Statistical analysis was performed with Chi-square test for all USPH parameters. Results: the three tested groups recorded a one hundred percent retention rate after 18 months follow up period. Concerning marginal adaptation, marginal discoloration, anatomical form, surface texture, and color matching, there was a significant difference (p˂0.05) between the three tested groups after 12 & 18 months. After 12 & 18 months, SEM analysis of the marginal seal revealed a statistically significant difference between the three groups. Conclusion: Bulk fill resin composite restorations showed satisfactory acceptable clinical performance after 18 months of clinical service compared to self-adhesive flowable composites, and Viscalor Bulk Fill composite demonstrated excellent results with considerable changes in marginal integrity as a consequence of thermal viscous technology and increased adaptability of restorations toward cavity walls and margins (AU)

Objetivo: este ensaio clínico randomizado duplo-cego avaliou o desempenho clínico de restaurações de resina Bulk Fill Termo-Viscosa, resina autoadesiva Flowable e Filtek Bulk Fill Composites em cavidades Classe I durante um período de 18 meses. Material e Métodos: 20 indivíduos com idade entre 30 e 45 anos participaram da pesquisa. Cada paciente deveria ter pelo menos três lesões de cárie oclusais de Classe I nos molares. Eles foram divididos aleatoriamente, com n=20 dentes representando cada material testado. Grupo I (Futurabond M+ e VisCalor Bulk Fill aquecido em dispensador viscolar a 68 °C por 30s e colocado em uma espessura de 4 mm), Grupo II (resina composta autoadesiva Fusio Liquid Dentin colocada em uma camada fina (incremento de 1 mm)) e Grupo III (resina composta Single Bond Universal e Filtek Bulk Fill Posterior aplicado em espessura de 4 mm sem aquecimento). Usando os critérios (USPHS), todas as restaurações foram avaliadas clinicamente no início, 6 meses, 12 meses e 18 meses. Usando uma réplica inversa, o selamento marginal das restaurações investigadas foi avaliado em MEV. A análise estatística foi realizada com o teste qui-quadrado para todos os parâmetros USPH. Resultados: os três grupos testados registraram uma taxa de retenção de cem por cento após um período de acompanhamento de 18 meses. Em relação à adaptação marginal, descoloração marginal, forma anatômica, textura da superfície e combinação de cores, houve uma diferença significativa (p˂0,05) entre os três grupos testados após 12 e 18 meses. Após 12 e 18 meses, a análise SEM do selamento marginal revelou uma diferença estatisticamente significativa entre os três grupos. Conclusão: as restaurações de resina composta Bulk Fill apresentaram desempenho clínico aceitável satisfatório após 18 meses de atendimento clínico em comparação com as resinas compostas fluidas autoadesivas, e a resina composta Viscalor Bulk Fill demonstrou excelentes resultados com mudanças consideráveis na integridade marginal, como consequência da tecnologia viscosa térmica e maior adaptabilidade de restaurações nas paredes e margens da cavidade (AU)

Clinical follow-up at 18 months of two bulk fill occlusal composite resins: a double-blind randomized clinical study / Seguimiento clínico a 18 meses de dos resinas compuestas oclusales bulk fill: estudio clínico aleatorio doble ciego

Objetive: To compare the clinical behavior of two types of Bulk Fill composite resins and a nanohybrid resin at 18 months in occlusal restorations. Material and Methods: Three occlusal restorations were performed in each one of the 55 participants. They were randomly distributed into three groups, TN: Tetric-N-Ceram Bulk-Fill, FK: Filtek Bulk-Fill, and Z350: Filtek Z350XT. Adhesive techniques and restorative procedures were performed according to the manufacturer's instructions for each restorative material used. In TN and FK an increment of 4mm was applied, and in Z350 increments of ≤2mm depth were applied. Two calibrated operators evaluated the restorations at baseline and at 18 months using the FDI World Dental Federations system (1: excellent, 2: good, 3: satisfactory, 4: unsatisfactory, 5: poor) for clinical marginal staining (MS) properties, fracture-retention (FR), superficial texture (ST), marginal integrity (MI), postoperative sensitivity (PS) and caries (C). Kruskal-Wallis and Wilcoxon were used to compare the 3 groups at 18 months (5% significance). Results: 38 patients with a total of 114 restorations were assessed, being evaluated with excellent clinical behavior; MI, 78.9% in Z350, 89.51% in TN and 81.6% in FK; ST 73.5% in Z350, 86.8% in TN, and 84.2% in FK; MS 84.2% in Z350, 84.2% in TN, and 91.2% in FK; PS 100% in Z350 and 97.3% in TN and FK; in C and FR, 100% in the 3 groups. There were no significant differences between the three groups (p>0.05). Conclusion: The three resins studied presented a good clinical performance at 18 months without showing significant differences in the clinical properties evaluated.

Objetivo: Comparar el comportamiento clínico a 18 meses en restauraciones oclusales entre dos tipos de resinas compuestas Bulk Fill y una resina nanohíbrida. Material y Métodos: En 55 participantes se realizaron 3 restauraciones oclusales en cada paciente, distribuidas aleatoriamente en 3 grupos, TN: Tetric-N-Ceram Bulk-Fill, FK: Filtek Bulk-Fill y Z350: Filtek Z350XT. Las técnicas adhesivas y procedimientos restauradores fueron realizados según las instrucciones de los fabricantes de cada material restaurador utilizado. En TN y FK se aplicó un incremento de 4mm y en Z350 se aplicó incrementos ≤ 2 mm de profundidad. Dos operadores calibrados evaluaron las restauraciones al baseline y a los 18 meses mediante el sistema FDI World Dental Federations (1: excelente, 2: aceptable, 3: suficiente, 4: insatisfactorio, 5: inaceptable) en las propiedades clínicas de tinción marginal (TM), fractura-retención (FR), textura superficial (TS), integridad marginal (IM), sensibilidad postoperatoria (SP) y caries (C). Se utilizó Kruskal-Wallis y Wilcoxon para la comparación de los 3 grupos a 18 meses (significancia de 5%). Resultados: Se controlaron 38 pacientes con un total de 114 restauraciones, siendo evaluados con comportamiento clínico excelente; IM, 78.9% en Z350, 89.51% en TN y 81.6% en FK; TS 73.5%, en Z350, 86.8% en TN y 84.2% en FK; TM, 84.2% en Z350, 84.2% en TN y 91.2% en FK; SP 100% en Z350 y 97,3% en TN y FK; en C y FR 100% en los 3 grupos. No hubo diferencias significativas entre los 3 grupos (p>0,05). Conclusión: Las 3 resinas estudiadas presentaron un buen desempeño clínico a 18 meses sin mostrar diferencias significativas en las propiedades clínicas evaluadas.

EVALUATION OF EFFECT OF EXPIRED TABLET ON SOIL PHYSICAL PROPERTIES: A CASE STUDY OF RANOZEX TABLET

Pharmaceutical waste can result from many locations and from many activities in health care facilities. They generate medicines waste which are compounding from pharmacy. In the present study, an attempt has been made to know the effect of Ranozex expired tablet on soil physical quality. The expired tablets were applied at a concentration of 150 mg, 250 mg, 500 mg, 750 mg and 1g. The expired ranozex tablets was mixed with sandy loam clay soil and kept for observation for 7 to 27 days respectively. The experimental setup was maintained till 27 days, at every 7 days intervals, the soil was extracted and subjected to selected physical properties such as bulk density, particle density, water holding capacity and moisture content. From the results, it was found that, the bulk density and particle density were found to be reduced. The percentage of water holding capacity was found to be higher during the experimental period

Clinical evaluation of bioactive resin-modified glass ionomer and giomer in restoring primary molars A randomized, parallel-group, and split-mouth controlled clinical study

Aim: This study aims to evaluate and compare the clinical performance of two restorative materials – bioactive resin-modified glass ionomer (ACTIVA BioACTIVE restorative) and giomer hybrid composite (Beautifil Flow Plus) in restoring class I carious primary molars. Materials and Methods: The split-mouth randomized controlled study was conducted on 100 primary molars from 50 children (28 – males, 22 – females) from 50 children in age range of 5-9 years (Mean-7.29±1.34) with at least two occlusal carious lesions on either maxillary or mandibular primary molars. Each child had both the control and the experimental teeth restored with respective restorative materials, Group I (Control, n = 50) ? Giomer, Group II (Experimental, n = 50) ? Bioactive resin-modified glass ionomer. The restorations were evaluated by two independent investigators using modified United State Public Health Service criteria at immediate postoperative, 6 months, and 12 months. The Chi-square test was used for the statistical analysis after collecting the data. Results: At the 12-month follow-up, 33 children (66 teeth) reported with an attrition rate of 33%. The color match between the groups was not statistically significant at all intervals. The marginal discoloration, marginal integrity, anatomic form, and retention had no significant difference at 6 months. But at 12 months, there was a statistically significant difference between the groups with p value of 0.04,<0.001,<0.02 and <0.001 respectively. respectively. At 12 months, there was no postoperative sensitivity in both groups. Conclusion: Bioactive resin-modified glass ionomer with enhanced properties can be used as an effective restorative material, especially in children with excessive salivation.

Pre-Heating effect on the microhardness and depth of cure of Bulk-Fill composite resins / Efecto del precalentamiento de las resinas compuestas Bulk-Fill en la microdureza y la profundidad de curado

Abstract The aim of this study was to investigate the effect of preheating three bulk-fill and one conventional composite resin on the Vickers microhardness and depth of cure of these composites. In this study, three bulk-fill composites- SDR Plus (SDR), Estelite BULK FILL Flow (EST), Admira® Fusion x-tra (AFX), and one conventional composite resin G-ænial POSTERIOR (GP) were used as the control group. The samples were obtained at room temperature (24°C) and at 55°C in T2 mode after being placed in a heating device for 10 minutes. The samples were divided into eight groups (n=10) according to the type of material and heating process that was utilized (preheated and nonheated). All samples were tested with a Vickers microhardness (VHN) tester on the bottom and top surfaces. The first measurements were obtained at baseline; the second set of measurements was performed after the samples were stored in distilled water at 37°C for 24 hours. The depth of cure was calculated using a bottom/top hardness ratio of measurements. Statistical analysis was performed utilizing the SPSS V23 and Shapiro-Wilk tests. Lastly, the Duncan test was used for multiple comparisons (p<0.05). While the VHN increased after the preheating procedure in bulk-fill composites, it decreased in GP. There was no difference between the baseline and the 24-hour VHN values in SDR and GP. After 24 hours, while the VHN of EST increased, the VHN of AFX decreased. There was no difference between the hardness ratios of the AFX and EST samples (p<0.001) and hardness ratios were greater than GP and SDR. When comparing the baseline and the 24- hour values, the VHN depended on the type of materials. Sufficient curing depth was obtained in all groups with a thickness of 2mm.

Resumen El objetivo fue investigar el efecto del precalentamiento de tres resinas Bulk-fill, una resina compuesta convencional sobre la microdureza Vickers y la profundidad de curado de estas resinas. Se utilizaron tres composites Bulk-Fill-SDR Plus (SDR), Estelite BULK FILL Flow (EST), Admira® Fusion x-tra (AFX), y una resina compuesta convencional G-ænial POSTERIOR (GP) como grupo de control. Las muestras se obtuvieron a temperatura ambiente (24°C) y a 55°C en modo T2 después de haber sido colocadas en un dispositivo de calentamiento durante 10 minutos. Se dividieron en ocho grupos (n=10) según el tipo de material y el proceso de calentamiento que se utilizó (precalentado y no calentado). Se probaron con un medidor de microdureza Vickers (VHN) en las superficies inferior y superior. Las primeras mediciones se obtuvieron en la línea de base; la segunda se realizó después de que las muestras se almacenaran en agua destilada a 37°C durante 24 horas. La profundidad de curado se calculó utilizando una relación de dureza inferior/ superior de las mediciones. El análisis estadístico se realizó utilizando el SPSS V23 y las pruebas de Shapiro-Wilk. Por último, se utilizó la prueba de Duncan para las comparaciones múltiples (p<0,05). VHN aumentó tras el procedimiento de precalentamiento en las resina Bulk-Fill, disminuyó en los GP. No hubo diferencias entre los valores de VHN de referencia y de 24 horas en SDR y GP. Después de 24 horas, mientras que el VHN de EST aumentó, el VHN de AFX disminuyó. No hubo diferencias entre los ratios de dureza de las muestras de AFX y EST (p<0,001) y los ratios de dureza fueron mayores que los de GP y SDR. Al comparar los valores de referencia y los de 24 horas, el VHN dependió del tipo de materiales. Se obtuvo una profundidad de curado suficiente en todos los grupos con un grosor de 2mm.

Restauración clase II MOD mediante uso de resina bulk-fill fluida y resina de estratificación natural: combinando fortalezas en una preparación extensa / Class II MOD restoration using bulk-fill flowable and natural layering resin composites: combining strengths in an extensive preparation

RESUMEN La restauración de grandes preparaciones cavitarias clases II MOD es un escenario clínico de alta complejidad. Elegir correctamente una resina compuesta y planificar la secuencia de estratificación permitirá mejorar la adaptación de las masas de resina y controlar el estrés de contracción de polimerización. En el siguiente reporte de caso clínico, se expone el protocolo paso a paso para el uso combinado de una resina compuesta para estratificación de esmalte de alto índice de refracción para la restauración de los rebordes marginales perdidos y la superficie oclusal, junto a una resina compuesta bulk-fill de baja viscosidad para la reconstrucción dentinaria en un diente posterior con gran destrucción coronaria.

ABSTRACT The restoration of large class II MOD cavity preparations is a highly complex clinical scenario. Selecting correctly a composite resin and planning the stratification sequence will improve the adaptation of the composite resin masses and will control the polymerization shrinkage stress. In the following clinical case report, the step- by-step protocol of the combined use of an high-refractive-index enamel-like composite resin is shown for the restoration of lost marginal ridges and the occlusal surface, together with a low viscosity Bulk-Fill composite resin for dentine reconstruction in a highly damaged posterior tooth.

Development and validation of analytical methods by HPLC for quality control of avermectins and milbemycins in bulk samples

This work aims to develop analytical methods using high-performance liquid chromatography with a diode array detector (HPLC-DAD) for analysis and quantification of avermectins (AVMs) and milbemycins (MBMs) in bulk samples. First, the methods were optimized and some parameters such as temperature, flow rate, injection volume and mobile phase with different proportions of solvents were evaluated. The best chromatographic conditions were obtained using the Phenomenex® C18 (150 × 4.60 mm, 5 µm) column at a temperature of 20 °C, flow rate of 1.2 mL min-1, injection volume of 20 µL, and detection at 250 nm. Acetonitrile: ultrapure water (87: 13, v/v) was used as mobile phase for moxidectin and eprinomectin, and acetonitrile: methanol: ultrapure water (53: 35: 12, v/v/v) for abamectin and ivermectin. Under these conditions satisfactory results were obtained, with appropriate limits of detection and quantification, acceptable linearity, precision, accuracy, and robustness. These methods satisfy the need for analytical methods for the multi-determination of MBMs and the B1a and B1b forms of AVMs by HPLC-DAD, which can be considered simple, effective, innovative and should aid in the development of the fiel

Evaluation of fracture strength and total void amount in composite restorations on endodontically treated teeth / Resistencia a la fractura y la cantidad total de burbujas en resinas compuestas de dientes tratados endodónticamente

ABSTRACT: The aim of the study was to investigate the fracture strength of different composite resins and the quantity of voids in conventional posterior composite, high- flow flowable composite, bulk-fill flowable composite, and fiber-reinforced composite. Forty-four caries-free, freshly extracted mandibular premolars were used for this study. Teeth were prepared for cavity and root canal treatment. Subsequently, root canal treatment was applied to the teeth and cavities in order to prepare them for restorations. The specimens were then divided into four groups: group-1: Estelite Posterior; group-2: Estelite Flow Quick High Flow; group-3: Estelite Bulk-fill Flow; group-4: everX Posterior. One specimen from each experimental group was examined using micro-CT to perform measurement of voids. The fracture strength values of high-flow flowable, bulk-fill flowable, fiber-reinforced, and conventional micro- hybrid composites were found to be similar (p=0.497). EverX Posterior showed the highest fracture strength values (841.1±149.4 N), followed by Estelite Bulk-fill Flow (822.8±170.8 N). Volume of voids (%) obtained from Micro-CT analysis revealed that restorations with high-flow liner or bulk-fill flowable exhibited more voids. The fiber-reinforced composite showed the lowest percentage volume of incorporating voids and the highest fracture strength results.

RESUMEN: El objetivo del estudio fue investigar la resistencia a la fractura de diferentes resinas compuestas y la cantidad de burbujas en resinas posteriores convencionales, resinas fluidas de alto flujo, resinas fluidas tipo bulk-fill y resinas reforzados con fibras. Cuarenta y cuatro premolares mandibulares libres de caries, recién extraídos, fueron usados para este estudio. Los dientes se prepararon para el tratamiento de conductos radiculares y las cavidades para prepararlos para las restauraciones. Los especímenes se dividieron en cuatro grupos: Grupo-1: Estelite Posterior; Grupo-2: Estelite Flow Quick High Flow; Grupo-3: Estelite Bulk-fill Flow; Grupo-4: everX Posterior. Un espécimen de cada grupo experimental fue examinado usando micro-CT para realizar la medición de las burbujas. Los valores de resistencia a la fractura de los compuestos de alto flujo, flujo de relleno, reforzados con fibra y microhíbridos convencionales fueron similares (p=0,497). EverX Posterior mostró los valores más altos de resistencia a la fractura (841,1±149,4 N), seguido de Estelite Bulk-fill Flow (822,8±170,8 N). El volumen de las burbujas (%) obtenido del análisis de Micro-TC reveló que las restauraciones con revestimiento de alto flujo o con flujo de relleno a granel presentaban más huecos. El compuesto reforzado con fibra mostró el menor porcentaje de volumen de incorporación de vacíos y los resultados más altos de resistencia a la fractura.

Effect of handpiece light and material used in pulp chamber on dentin removal during root canal retreatment

Abstract This study evaluated the effect of the use of glass ionomer cement (GIC) and flowable bulk-fill resin composite (BFRC) for filling pulp chambers and the type of high-speed handpiece light used on dentin removal during access preparation for endodontic retreatment in molar teeth. Twenty maxillary molars were treated endodontically. BFRC (Opus Bulk Fill Flow APS, FGM) was used to fill the pulp chamber and replace coronal dentin (n = 10). In the remaining teeth, the pulp chamber was filled with GIC (Maxion R, FGM). Conventional resin composite (Opallis, FGM) was used to restore the enamel layer in all teeth. The samples in each group were divided into two subgroups, and the root canals were reaccessed using a handpiece with white or ultraviolet light. The teeth were scanned using micro-CT before and after root canal reaccess. The dentin volume removed was calculated and analyzed using 2-way analysis of variance and Tukey's test (α = 0.05). The crown and pulp chamber locations with dentin removal are described using frequency distribution. During the access, fewer pulp chamber walls were affected and a lower volume of dentin was removed from the pulpal floor in the group restored with GIC than in the group restored with BFRC. No effect was observed on the coronal dentin walls with respect to the filling protocols and type of light used. For dentin removal from the pulp chamber, handpieces with white light performed better than those with ultraviolet light, irrespective of the filling protocol used. The use of GIC to fill the pulp chamber and use of white handpiece light reduced dentin removal from the pulpal floor and resulted in fewer affected dentin walls.

Resumo Este estudo avaliou os efeitos do cimento de ionômero de vidro (GIC) e da resina composta fluida bulk fill (BFRC) usados como preenchimento da câmara pulpar; e o tipo de iluminação das turbinas de alta rotação na remoção dentinária após cavidades de acesso para retratamento endodôntico em dentes molares. Vinte molares superiores foram tratados endodonticamente. Dez dentes foram restaurados usando BFRC (Opus Bulk Fill Flow APS, FGM) para preencher a câmara pulpar e dentina coronária; e resina composta convencional (Opallis, FGM) para restaurar a camada de esmalte. Os outros dentes foram restaurados usando GIC (Maxion R, FGM) para preencher a câmara pulpar e resina composta (Opallis, FGM). As amostras foram divididas em dois grupos e os canais radiculares foram novamente acessados com turbina de alta-rotação com iluminação branca ou ultravioleta. Os dentes foram escaneados usando micro-CT antes e após o novo acesso ao canal radicular. O volume de dentina removida foi calculado e os dados foram analisados por ANOVA bidirecional e teste de Tukey (α=0,05). As regiões na coroa e na câmara pulpar que apresentaram dentina removida no acesso dos canais foram descritas por meio de distribuição por frequência. A reabertura do canal radicular com GIC resultou em menos paredes afetadas da câmara pulpar e menor volume de dentina removida no assoalho. Nenhum efeito foi observado nas paredes de dentina coronária considerando aos protocolos de preenchimento. A turbina de alta rotação com iluminação branca reduziu a remoção de dentina da câmara pulpar, independentemente do protocolo de restauração utilizado. O uso de turbina de alta rotação com iluminação branca e GIC para preencher a câmara pulpar reduziram a remoção de dentina do assoalho e afetaram menos paredes dentinárias.

Do dual-cure bulk-fill resin composites reduce gaps and improve depth of cure

Abstract This in vitro study aimed to evaluate the gaps length and depth of cure of dual-cure bulk-fill resin composites inserted in box-shaped preparations. Box-shaped preparations (4 mm deep) were made in fifteen human third-molars and divided into three groups according to the resin composites (n=5): Dual-cure bulk-fill BulkEZ (BEZ); Dual-cure bulk-fill HyperFIL (HF); and Tetric Evoceram Bulk-fill (TETRIC), as control. Gaps length (%) was evaluated in tooth-restoration interface with micro-computed tomography (µCT). The restorations were sectioned, and the degree of conversion (DC) and Knoop microhardness were evaluated at five depths (0.3, 1, 2, 3, and 4 mm). Microhardness data were statistically evaluated using absolute values (KHN) and relative values (microhardness percentages in relation to top). Gaps length (%) increased in the following order: BEZ=TETRIC<HF. The microhardness percentages in relation to top significantly decreased from 2 mm for TETRIC and 3 mm for HF. BEZ had constant microhardness and DC at all depths, while HF and TETRIC presented a significant decrease on DC at 4 mm. Dual-cure bulk-fill composites did not reduce gaps compared to light-cure bulk-fill, but they can improve depth of cure of bulk-filled restorations.

Resumo O objetivo neste estudo in vitro foi mensurar as fendas e a profundidade de polimerização de compósitos resinosos bulk-fill duais inseridos em preparos em forma de caixa. Os preparos em forma de caixa (4 mm de profundidade) foram realizados em quinze terceiros molares e separados em 3 grupos, de acordo com o compósito resinoso (n = 5): Bulk-fill dual BulkEZ (BEZ); Bulk-fill dual HyperFIL (HF); Tetric Evoceram Bulk-fill (TETRIC). O comprimento das fendas (%) foi avaliado na interface dente-restauração por meio de micro-tomografia computadorizada (µCT). As restaurações foram seccionadas e o grau de conversão (GC) e microdureza Knoop foram avaliados em cinco profundidades (0,3, 1, 2, 3 e 4 mm). Os dados de microdureza foram avaliados estatisticamente por meio de valores absolutos e relativos (porcentagens de microdureza em relação ao topo). O comprimento das fendas (%) aumentou na seguinte ordem: BEZ = TETRIC <HF. O percentual de microdureza em relação ao topo diminuiu significativamente a partir de 2 mm para TETRIC e 3 mm para HF. BEZ apresentou percentuais de microdureza e de GC constantes em todas as profundidades, enquanto HF e TETRIC apresentaram decréscimo significativo no GC em 4 mm. Os compósitos resinosos bulk-fill duais não reduziram as fendas formadas quando comparados a um compósito bulk-fill fotopolimerizável; entretanto, os mesmos podem melhorar a profundidade de polimerização em restaurações de incremento único.

Discoloration of Bulk-Fill Versus Conventional Composites: A Spectrophotometric Evaluation / Decoloración de resinas Bulk vs resinas convencionales: Evaluación espectrofotométrica

ABSTRACT: Purpose: The purpose of this study was to evaluate the discoloration of a dual-cure bulk-fill (DCBF) and light-cure bulk-fill (LCBF) composites relative to conventional composites (CC) after water and coffee immersion. Methods: One- hundred disc-shaped specimens (8mm in diameter × 4mm thickness) were prepared using five commercially available composites (n=10); two LCBF (XB-X-trafil Voco, FB-FiltekTM Bulk Fill), one DCBF (FU-Fill-upTM Coltene), and two CC (CE-Clearfil Majesty ES2, EQ-Estelite ΣQuick). Initial and final color readouts were measured with a spectrophotometer (Easyshade,Vita) according to the CIELAB color system. Statistical analyses were performed using 2-way ANOVA with Bonferroni adjustment to evaluate ΔE, ΔL, Δa, and Δb parameters (pFB≥XB>EQ≥CE in water immersion groups and XB>FB>EQ≥FU≥CE in coffee immersion groups. Conclusion: Within the limitations of this study, DCBF composite is more susceptible to intrinsic discoloration compared to LCBF and CC. However, DCBF exhibited lower extrinsic discoloration than LCBF and comparable with CC after coffee immersion. Depending on their chemical and structural compositions, composites will exhibit color change, which compromises the esthetic performance of composite restorations.

RESUMEN: Propósito: El propósito de este estudio fue evaluar la decoloración de resinas bulk de curado dual (DCBF) y bulk activadas por fotopolimerización (LCBF) en relación con las resinas convencionales (CC) después de la inmersión en agua y café. Métodos: Se prepararon cien muestras en forma de disco (8mm de diámetro × 4mm de espesor) utilizando cinco resinas compuestas disponibles comercialmente (n=10); dos LCBF (XB-X-trafil Voco, FB-FiltekTM Bulk Fill), un DCBF (FU-Fill-upTM Coltene) y dos CC (CE-Clearfil Majesty ES2, EQ-Estelite ΣQuick). Las lecturas de color inicial y final se midieron con un espectrofotómetro (Easyshade, Vita) de acuerdo con el sistema de color CIELAB. Los análisis estadísticos se realizaron utilizando ANOVA de 2 vías con ajuste de Bonferroni para evaluar los parámetros ΔE, ΔL, Δa y Δb (pFB≥XB>EQ≥CE en los grupos de inmersión en agua y XB>FB>EQ≥FU≥CE en los grupos de inmersión en café. Conclusión: Dentro de las limitaciones de este estudio, la resina DCBF es más susceptible a la decoloración intrínseca en comparación con LCBF y CC. Sin embargo, DCBF mostró una decoloración extrínseca más baja que LCBF y comparable con CC después de la inmersión en café. Dependiendo de sus composiciones químicas y estructurales, los composites mostrarán cambios de color, lo que compromete el desempeño estético de las restauraciones de resinas con el tiempo.

Bond Strength Evaluation of Bulk- fill Composites to Dentin Under Different Surface Treatments / Evaluación de la resistencia adhesiva de las resinas bulk-fill a la dentina con diferentes tratamientos de superficie

ABSTRACT: Purpose: The aim of this study is to compare the shear bond strength of three high-viscosity bulk-fill composite resins applied as single layers of 4mm thickness and of one microhybrid composite resin applied incrementally with a thickness of 2mm on dentin surfaces prepared with different surface preparation methods. Materials and Methods: A total of 132 caries-free human molars whose dentines had been exposed were used. Three groups, each containing 44 teeth, were formed. The acid group was etched with 32% phosphoric acid; laser group was etched with Er, Cr; YSGG laser and the control group was prepared with silicon carbid paper. Following the application of bonding agent, composite resin materials were applied on teeth using teflon moulds of 4x4mm. The samples were then subjected to shear bond strength tests. Two-way variance analysis and Tukey HSD multiple comparison test were applied on collected data. Results: There was a significant difference between surface treatment methods used regarding shear bond strength (P0.05). Conclusions: Laser etching of the dentin tissues is not as effective as acid etching. Bulk-fill composites had similar effects compared with conventional composite resins with regard to bonding strength. More in vitro studies supported with clinical data are required to investigate the performance of bulk-fill composites and laser.

RESUMEN: Propósito: El objetivo de este estudio es comparar la resistencia adhesiva al cizallamiento de tres resinas compuestas de relleno de alta viscosidad aplicadas como capas individuales de 4 mm de espesor y de una resina compuesta microhíbrida aplicada de forma incremental con un espesor de 2mm en superficies de dentina preparadas con diferentes métodos de preparación de la superficie. Materiales y métodos: Se utilizaron un total de 132 molares humanos sin caries cuyas dentinas habían sido expuestas. Se formaron tres grupos, cada uno con 44 dientes. El grupo ácido se grabó con ácido fosfórico al 32%; el grupo láser se grabó con Er, Cr; el láser YSGG y el grupo de control se preparó con papel de carburo de silicio. Después de la aplicación del agente adhesivo, se aplicaron materiales de resina compuesta en los dientes utilizando moldes de teflón de 4x4mm. A continuación, las muestras se sometieron a pruebas de resistencia adhesiva al cizallamiento. Se aplicó el análisis de varianza bidireccional y la prueba de comparación múltiple Tukey HSD a los datos recogidos. Resultados: Hubo una diferencia significativa entre los métodos de tratamiento de superficie utilizados en cuanto a la resistencia adhesiva al cizallamiento (P0,05). Conclusiones: El grabado láser de los tejidos de la dentina no es tan eficaz como el grabado al ácido. Las resinas de relleno bulk-fill tuvieron efectos similares en comparación con las resinas compuestas convencionales en lo que respecta a la rsistencia adhesiva. Se necesitan más estudios in vitro apoyados con datos clínicos para investigar el rendimiento de los composites de relleno y el láser.

Fracture Resistance of Teeth Restored with Bulk-Fill and Fiber-Reinforced Composites in Class II Cavities / Resistencia a la fractura de dientes restaurados con resinas de relleno y resinas reforzadas con fibra en cavidades clase II

ABSTRACT: This study aimed to evaluate the fracture resistance of teeth restored with conventional, bulk-fill, and fiber-reinforced composite materials regarding intact teeth. Standard cavities were prepared on 70 sound third molar teeth. The teeth were randomly divided into six groups: intact teeth, conventional Bis-GMA based composite, fiber-reinforced composite, Bis-GMA based bulk-fill composite, ormocer based bulk-fill composite, glass containing resin-based bulk-fill composite. The data was obtained by a Universal Testing Machine and analyzed statistically. Fracture resistance of the teeth restored with conventional composite was significantly lower than the other groups (p0.05). The obtained data showed that restoring teeth with bulk-fill and fiber-reinforced composites could be recommended in Class II cavities.

RESUMEN: El objetivo del presente estudio fue evaluar la resistencia a la fractura de los dientes restaurados con materiales compuestos convencionales, de relleno y reforzados con fibras, en relación con los dientes intactos. Se prepararon cavidades estándar en 70 dientes de terceros molares sanos. Los dientes se dividieron al azar en seis grupos: dientes intactos, compuesto convencional basado en Bis-GMA, compuesto reforzado con fibra, compuesto de relleno a base de Bis-GMA, compuesto de relleno a base de ormocer, compuesto de relleno a base de vidrio que contiene resina. Los resultados fueron obtenidos utilizando una máquina universal de pruebas y analizados estadísticamente. La resistencia a la fractura de los dientes restaurados con el composite convencional fue significativamente menor que la de los otros grupos (p0,05). Los datos obtenidos mostraron que la restauración de dientes con composites de relleno y reforzados con fibra podría ser recomendada en cavidades de Clase II.

Organic carbon in soils with different systems of use in Tacarimena Yopal, Colombia / Carbono orgánico en suelos con diferentes sistemas de uso en Tacarimena Yopal, Colombia

ABSTRACT Soil is an important carbon reservoir as it can store twice the amount that atmosphere does and three times the biomass, which makes it a key component for climate change (CC) mitigation projects. It is important to know the potential of soil organic carbon storage (SOC) in the main uses of the soli and their expected dynamics due to potential use changes. SOCS is estimated in 7 of the dominant land use systems in the area of the study, with 5 replicas as follows: 1) banana with shade (SAF+banana); 2) cocoa with shade (Ca+S); 3) citrus (C); 4) low silvopastoral system (SSPB); 5) high silvopastoral system (SSPA); 6) gallery forests (BG); and 7) bush forest (MM). SOC concentration was analyzed in samples composed of 25 soil sub-samples per plot, and the DA was estimated with the cylinder method in a simple per plot. All land uses studied can mitigate CC when storing SOC. BG was the system that showed the highest carbon storage. On the other hand, SAF+banana stored the least SOC (72,7 vs 33,4Mg/ha, respectively). Changes in land use can cause CO2 emissions or an addition in carbon fixation. Changes in land use that increase SOC allow CC mitigation, which makes them feasible for funding, thus allowing an improvement in the livelihood of local producers.

RESUMEN El suelo es un reservorio importante de carbono, ya que puede almacenar el doble de lo contenido por la atmósfera y el triple de la biomasa. Esto lo constituye en un componente clave para proyectos de mitigación del cambio climático (CC). Es importante conocer el potencial de almacenamiento de carbono orgánico del suelo (COS) en los principales usos del suelo y su dinámica esperada, por potenciales cambios de uso. Se estima el COS en los siete de los sistemas de uso del suelo dominantes en el área de estudio, con cinco réplicas, así: 1) plátano con sombrío (SAF+plátano); 2) cacao con sombrío (Ca+S); 3) cítricos (C); 4) sistema silvopastoril bajo (SSPB); 5) sistema silvopastoril alto (SSPA); 6) bosques de galería (BG) y 7) mata de monte (MM). La concentración de COS fue analizada en muestras compuestas de 25 submuestras de suelo por parcela y la DA, se estimó con el método del cilindro en una muestra por parcela. Todos los usos del suelo estudiados pueden mitigar el CC al almacenar COS. El BG fue el sistema que presentó el mayor almacenamiento de carbono; por el contrario, el SAF+plátano almacenó el menor COS (72,7 vs 33,4Mg/ha, respectivamente). Cambios de uso del suelo pueden causar emisión de CO2 o adicionalidad en la fijación de carbono. Cambios de uso del suelo que incrementen el COS permiten la mitigación del CC, pudiendo ser susceptibles de financiamiento, lo que permite mejorar los medios de vida de los productores locales.

Microhardness homogeneity of RBCs light-cured with a multiple-peak LED and surface characterization after wear

Abstract This in vitro study evaluated the effect of the beam homogeneity of a multiple-peak light-curing unit on the surface microhardness and the effect of toothbrushing wear on the microhardness, surface roughness, roughness profile, volume loss, and gloss retention of incremental and bulk-fill resin-based composites (RBCs). A LED light-curing unit (VALO) with four LEDs at the tip end (405, 445, 465A, and 465B nm emission peak) was used according to each manufacturer-recommended time to obtain disks (n=10) of six RBCs: Estelite Sigma Quick, Charisma Classic, Tetric EvoCeram Bulk Fill, Filtek Z250, Filtek Supreme Ultra, and Filtek Bulk Fill. Microhardness values were obtained according to each LED positioning of the light-curing unit on the top surface of the RBCs and were analyzed before and after toothbrushing regarding microhardness, surface roughness, roughness profile, volume loss, and gloss retention. Microhardness was considered homogeneous on the top surface regardless of the type of RBC or wavelength tested (p>0.05). Overall, toothbrushing did not reduce the microhardness of the RBCs but influenced the gloss values for most RBCs (p<0.001). Charisma Classic presented the greatest surface roughness and roughness profile after toothbrushing (p<0.05). Volume loss did not differ among RBCs (p>0.05). In conclusion, different wavelengths of the LED did not affect the top surface microhardness, regardless of the RBCs tested; and bulk-fill composites presented similar surface changes (microhardness, surface roughness, roughness profile, volume loss, and gloss retention) when compared to conventional composites after toothbrushing.

Resumo Este estudo in vitro avaliou a homogeneidade do feixe de um fotopolimerizador de múltiplos picos na microdureza superficial e o efeito da escovação na microdureza, rugosidade superficial, perfil de rugosidade, perda de volume e retenção do brilho de compósitos a base de resina (RBCs) incrementais ou bulk-fill. Um fotopolimerizador LED (VALO) com quatro LEDs na ponteira (405, 445, 465A e 465B nm de pico de emissão) foi usado de acordo com o tempo recomendado por cada fabricante para obtenção de discos (n=10) de seis RBCs: Estelite Sigma Quick, Charisma Classic, Tetric EvoCeram Bulk Fill, Filtek Z250, Filtek Supreme Ultra e Filtek Bulk Fill. Os valores de microdureza foram obtidos seguindo o posicionamento de cada LED na superfície superior das amostras e foram analisados antes e após a escovação quanto a microdureza, rugosidade superficial, perfil de rugosidade, perda de volume e retenção do brilho. A microdureza foi considerada homogênea no topo da superfície, independentemente do tipo de RBCs ou comprimento de onda testados (p>0.05). No geral, a escovação não reduziu a microdureza das RBCs, mas influenciou o brilho para a maioria das RBCs (p<0.001). Charisma Classic apresentou os maiores valores de rugosidade superficial e perfil de rugosidade após a escovação (p<0.05). A perda de volume não diferiu entre as RBCs (p>0.05). Em conclusão, os diferentes comprimentos de onda do LED não alteraram a microdureza do topo da superfície, independentemente das RBCs testadas; e as resinas bulk-fill apresentaram alterações superficiais similares (microdureza, rugosidade superficial, perfil de rugosidade, perda de volume e manutenção do brilho) quando comparadas às resinas convencionais após a escovação.

Defoliation heights for palisade grass cv. Marandu in silvopastoral system / [Alturas de desfolhação para capim-marandu em sistema silvipastoril]

The objective was to test the response of Urochloa brizantha cv. Marandu in monoculture and in silvopastoral system (SPS), at two distances from the trees, and define the best defoliation height for SPS. Four intermittent defoliation heights (25, 35, 45 and 55cm) and two distances from tree lines (2.5 and 5.0m) were evaluated in the SPS with a control defoliated with 25cm in full sun. The experiment was performed in a randomized block design with 3 replicates in a 4 × 2 + 1 split plot scheme. The control had higher forage accumulation (46.9kg/ha. day) than the SPS (31.1kg/ha. day). The bulk density was also higher in the control (0.89mg/cm³) than in SPS (0.48mg/cm³). The percentage of leaves (78.06%) and leaf/stem ratio (6.04) did not differ among the treatments. In the SPS, there was an increase of 31.07% in forage accumulation from 25 to 55cm. The forage accumulation and bulk density of Urochloa brizantha cv. Marandu in monoculture is greater than in the SPS regardless of the management goal and the distance from trees. The goal of 55cm in the SPS presented greater forage accumulation.(AU)

O objetivo foi testar a resposta de pastos de Urochloa brizantha cv. Marandu em monocultivo e em sistema silvipastoril (SSP), a diferentes distâncias das árvores, bem como definir qual altura de desfolhação é a mais indicada para manejo em SPS. Foram avaliadas quatro alturas de desfolhação intermitente (25, 35, 45 e 55cm) e duas distâncias das linhas de árvores (2,5 e 5,0m), no SPS, e uma testemunha desfolhada com 25cm, em pleno sol. O delineamento foi em blocos ao acaso, com três repetições, em esquema de parcelas subdivididas 4 × 2 + 1. O controle apresentou maior acúmulo de forragem (46,9kg/ha.dia) que a média do SSP (31,1kg/ha.dia). A densidade volumétrica da forragem do controle (0,89mg/cm³) foi maior que a do SSP (0,48mg/cm³). A porcentagem de folhas (78,06%) e a relação folha/colmo (6,04) não diferiram entre os tratamentos. O aumento das alturas de 25 para 55cm no SSP resultou em aumento de 31,07% no acúmulo de forragem. O acúmulo e a densidade volumétrica da forragem são maiores no monocultivo, independentemente da meta de manejo e da distância das árvores no sistema silvipastoril. A meta de 55cm no silvipastoril apresenta maior acúmulo de forragem.(AU)