Extraction and characterization of an exopolysaccharide from a marine bacterium / Extracción y caracterización de un exopolisacárido de una bacteria marina

The marine bacterial exopolysaccharides (EPS) have transfigured the biotech sector with their myriad applications and prospects. This work was carried out to characterize and analyze the functional and biochemical properties of an EPS (EPS-DR3A) produced by a marine bacterium, Pseudoalteromonas sp. YU16-DR3A. The bacterium was cultured in Zobell marine broth for the production of EPS. The extracted EPS designated as EPS-DR3A was composed of 69% carbohydrates and 7.6% proteins with a molecular weight of 20 kDa. FT-IR spectra showed the presence of different functional groups. The monosaccharide analysis performed using GC–MS showed the presence of fucose, erythrotetrose, ribose, and glucose as monomers. EPS-DR3A showed excellent emulsifying activity against the tested hydrocarbons and food oils with stable emulsions. Rheological analysis of EPS-DR3A revealed the pseudoplastic behavior. The EPS-DR3A displayed good thermal stability with a degradation temperature of 249 °C and a melting point at 322 °C. Further, it had the ability to scavenge DPPH and nitric oxide free radicals with good total antioxidant activity. The in vitro biocompatibility study of EPS-DR3A showed high degree of biocompatibility with human dermal fibroblast cells at the tested concentrations. Taken together, the findings such as thermostability, emulsifying activity, pseudoplasticity, antioxidant activity, and biocompatibility of EPS-DR3A make this biomolecule an important candidate for a wide range of biomedical applications.(AU)

Diseño de estudios Gauge R&R cruzado y anidado para la validación de los modelos matemáticos de Heckel y Ryshkewitch-Duckworth / Design of crossed and nested Gauge R&R studies for the validation of the Heckel and Ryshkewitch-Duckworth mathematical models

INTRODUCCIÓN: Los estudios gauge permiten ganar información sobre el desempeño de procesos y son de utilidad para control de calidad, así como identificación de fuentes de variación. El objetivo del presente estudio, fue diseñar y analizar sistemas de medición para los modelos de Heckel y Ryshkewitch-Duckworth para caracterizar materiales, a través de estudios Gauge R&R. MÉTODO: Estudio Gauge R&R cruzado para evaluar el sistema de medición del peso y estudio Gauge R&R anidado para el sistema de la resistencia a la fractura. RESULTADOS: Ambos estudios cumplieron con los supuestos de normalidad, varianza constante e independencia de los datos, por lo que fue posible determinar la significación de las fuentes de variación (factores) mediante un ANOVA así como su porcentaje de contribución. Para el estudio Gauge R&R cruzado los punzones evaluados contribuyen a la variación de la medición de manera significativa y en un 97,38% de la variación total; los operadores contribuyen en menos del 1% y de manera no significativa y no existió interacción parte-operador. Respecto al estudio Gauge R&R anidado, se identificó que el operador no influyó de manera significativa en la variabilidad de la medición y que ésta es atribuible en un 95% a las diferencias existentes entre las tabletas evaluadas. CONCLUSIONES: Se realizó el diseño, ejecución y análisis de los sistemas de medición, destacando que en ambos estudios la principal fuente de variación fueron las partes evaluadas y que los operadores no contribuyen en la variabilidad de las mediciones, por lo que los estudios pueden usarse para evaluar los modelos matemáticos y durante el control estadístico de un proceso

INTRODUCTION: Gauge studies allow gaining information about the performance of processes and are very useful tools for quality control and identification of variability sources. The objective of the present study was design and analyzes measurement systems for the Heckel and Ryshkewitch-Duckworth models for characterizing materials, through Gauge R&R studies. METHOD: Crossed Gauge R&R study for the evaluation of weight measurement system and nested Gauge R&R study for the system of tablet hardness. RESULTS: Both studies fulfilled with the assumptions of normality, constant variance and data independence, therefore it was possible to estimate the significance of variation sources (factors) through ANOVA and their contribution percentage. The crossed Gauge R&R study showed that the flat punches contributed to variability of the measurement in a significant manner in 97.38% of the total variation of the study; operators did it in less than 1% and they were not statistically significant and there was no Part-Operator interaction. With respect to the nested Gauge R&R study, it was found that the operator did not influence in a statistically significant way in the variability of the measurement and it was attributable in 95% to the existing differences between the tablets evaluated. CONCLUSIONS: Design, run and analysis of the measurement systems was performed, we remark that in both of the studies the main source of variability were the parts evaluated and that operators did not contribute to variability in the measurements; therefore, both studies could be used to evaluate the Heckel and Ryshkewitch-Duckworth mathematical models and also for statistical process control

Microencapsulación de peróxido de hidrógeno para la elaboración de un caramelo de goma blanqueador dental y evaluación in vitro mediante un método colorimétrico / Microencapsulation of hydrogen peroxide for the development of a dental whitening gummy candy and in vitro evaluation using a colorimetric method

INTRODUCCIÓN: La apariencia y el color de los dientes es una preocupación común para los pacientes por lo que hay una creciente necesidad de contar con tratamientos que mejoren la estética dental. Por esa razón, en los últimos 20 años la ciencia dental ha buscado nuevas técnicas y materiales capaces de reducir la discoloración dental. MÉTODO: Se prepararon pastillas de goma fantasía, caramelos de goma o gominolas que contenían dos concentraciones diferentes (7% y 14% m/v) de peróxido de hidrógeno microencapsulado por gelificación iónica. Durante 30 días se realizó un tratamiento diario de blanqueamiento dental in vitro para evaluar la acción blanqueadora de las dos formulaciones. La medición del color de la superficie de los dientes tratados se llevó a cabo utilizando una técnica colorimétrica. RESULTADOS: Se encontraron diferencias significativas entre los tratamientos de blanqueamiento con las dos formulaciones elaboradas en comparación con un grupo de control, siendo el esquema de dos procedimientos diarios con la formulación al 7% de peróxido de hidrógeno más efectivo que el de un único procedimiento diario con la formulación al 14%. CONCLUSIONES: Las dos formulaciones desarrolladas en este estudio tuvieron un mayor efecto de blanqueamiento in vitro en comparación con un grupo de control, y además se encontró que se logran mejores resultados al disminuir la concentración de peróxido si el número de aplicaciones aumenta para dosis diarias iguales

INTRODUCTION: The appearance and color of the teeth are common concerns for patients and are associated with an increased need for treatments that can improve dental aesthetics. For this reason, in the past 20 years, dental science has been searching for new techniques and materials able to reduce dental discoloration. METHOD: Gummy candies containing two different concentrations (7% and 14% w/v) of hydrogen peroxide microencapsulated by ionic gelation were prepared. In vitro tooth whitening treatment was carried out for 30 days to test the bleaching action of these formulations. The surface color of the treated teeth was measured using a colorimetric technique. RESULTS: Significant differences were found on comparing the whitening treatments for the two formulations with a control group, with two daily treatments using the formulation with 7% hydrogen peroxide being more effective for whitening than a daily single treatment using the formulation with 14 %. CONCLUSIONS: The two formulations developed had an in vitro higher bleaching effect in comparison with the control group, and in addition, better results were achieved if the daily dose was provided by more applications at a lower concentration of hydrogen peroxide

Comparación del porcentaje de áreas no obturadas entre la técnica de compactación lateral en frío y la técnica de compactación lateral con ultrasonido / Comparison of the percentage of non-filledventa areas between cold lateral compaction technique and lateral compaction with ultrasonic technique

OBJETIVO: Comparar, en un estudio experimental in vitro, el porcentaje de áreas no obturadas entre la técnica de compactación lateral en frío (TCL) y la técnica de compactación lateral con ultrasonido (TCLU). MATERIALES Y MÉTODOS: El estudio fue realizado en una muestra de 68 dientes humanos extraídos. Se asignaron de manera aleatoria en dos grupos de 34 dientes cada uno. Todos los dientes se cortaron a 16±1 mm de longitud desde el ápice hacia la corona, se instrumentaron con el sistema rotatorio Protaper Next (Dentsply) y se realizó protocolo de irrigación final con NaOCl al 2.5% y EDTA al 17% neutralizados con suero fisiológico entre ellos. El Grupo I se obturó con TCL y el Grupo II con TCLU. En ambos grupos se utilizó Sealapex como cemento. Los dientes fueron seccionados horizontalmente a 2, 4, 6 y 8 mm desde el ápice; cada corte se observó con un microscopio estereoscópico (56X) y se tomaron fotografías. Se calculó el porcentaje de área obturada con gutapercha, cemento y de áreas no obturadas, utilizando el programa ImageJ. El análisis de los resultados se llevó acabo mediante la suma de rangos de Wilcoxon. RESULTADOS: El grupo TCLU presentó un mayor porcentaje de gutapercha en el conducto radicular en comparación con el grupo TCL (94.4% y 87.4% respectivamente), menor porcentaje de áreas no obturadas (1.3% y 4.2%), y menor porcentaje de áreas ocupadas con cemento (3.8% y 7.2%). Las diferencias fueron estadísticamente significativas (P<0.05).CONCLUSIÓN: Los resultados de este estudio muestran que la modificación de la técnica de compactación lateral con ultrasonido descrita en esta investigación presenta resultados in vitro superiores a TCL

AIM: To compare, in an Experimental in vitro study, the percentage of non-filled areas between cold lateral compaction technique (CLT) and lateral compaction with ultrasonic technique (LUT). METHODS: The study was made on in a sample of 68 extracted human teeth. They were randomized into two groups of 34 teeth each. All teeth were cut 16±1 mm from the apex and instrumented with the Protaper Next rotary system (Dentsply) and a final irrigation protocol was performed with NaOCl 2.5% and EDTA 17% neutralized with normal saline solution between them. Group I was filled with CLT and Group II with LUT. In both groups Sealapex was used as a cement. The teeth were sectioned horizontally at 2, 4, 6 and 8 mm from the apex; slices were the viewed through a stereomicroscope (56X) and pictures were taken. The percentage of gutta-percha filled area, percentage of non-filled area and percentage of sealer filled area were calculated for each section using the ImageJ program. Statistical analysis was performed using the Wilcoxon Rank-Sum test. RESULTS: LUT had a higher percentage of gutta-percha in the root canal compared to CLT (94.4% and 87.4% respectively), lower percentage of non-filled area (1.3% and 4.2% respectively), and lower percentage of area occupied by sealer (3.8 % and 7.2% respectively). The differences were statistically significant(P <0.05).CONCLUSION: The results of this study showed that the modification of lateral compaction technique with ultrasonic described in this investigation presents in vitro results superior to CLT

Estudio de biocompatibilidad y osteointegración de nuevos materiales protésicos / Biocompatibility and osseointegration study of new prosthetic materials

OBJETIVO: Los implantes óseos son utilizados cada vez con mayor frecuencia en la práctica clínica y, entre los materiales, el Ti o sus aleaciones son los de mejor rendimiento por sus propiedades fisicoquímicas. Aleaciones como TiNbTa han demostrado mejorar las características biomecánicas del Ti puro comercial (c.p.), sin embargo, su capacidad osteointegradora necesita ser evaluada. El objetivo del presente estudio fue valorar la citotoxicidad y la capacidad de adhesión, proliferación y diferenciación de células osteoblásticas en cultivo, influida por discos de material TiNbTa frente a Ti c.p. MATERIALES Y MÉTODOS: Analizamos a los 4 y 7 días del cultivo la línea celular MC3T3, la viabilidad celular (AlamarBlue Cell Viability Reagent. Invitrogen, España), así como la proliferación y diferenciación celular (actividad de fosfatasa alcalina (ALP) y microscopía electrónica de barrido (Fijación para SEM). Se realizó la prueba t de Student para determinar diferencias estadísticamente significativas entre los dos grupos de discos de estudio. RESULTADOS: Los resultados obtenidos demuestran muy buena viabilidad celular durante el periodo de estudio, sin diferencias significativas para ambos materiales. Así mismo, detectamos una caída en los niveles de ALP que fue significativa para ambos componentes entre los días 4 y 7 del estudio (p < 0,05). Las imágenes de microscopía electrónica revelaron buena capacidad de adhesión al material, así como diferenciación celular frente a ambos tipos de discos. CONCLUSIONES: La aleación de TiNbTa como material para implantes óseos cuenta con una buena capacidad osteointegradora, además de resolver problemas de biomecánica que presenta el titanio puro como componente

OBJETIVE: Bone implants are increasingly used in clinical practice and, among the materials, Ti or its alloys are offer the best performance given their physicochemical properties. Alloys such as TiNbTa have been shown to improve the biomechanical characteristics of commercial pure Ti (c.p.), however, its osseointegration capacity needs to be evaluated. The objective of the present study was to assess the cytotoxicity and the adhesion, proliferation and differentiation capacity of osteoblastic cells in culture, influenced by discs of TiNbTa material versus Ti c.p. MATERIAL AND METHODS: At 4 and 7 days after culture, we analyzed the MC3T3 cell line, cell viability (AlamarBlue Cell Viability Reagent. Invitrogen, Spain), as well as cell proliferation and differentiation (alkaline phosphatase activity (ALP) and scanning electron microscopy (Fixation for SEM) Student's t test was performed to determine statistically significant differences between the two groups of study discs. RESULTS: The results obtained show very good cell viability during the study period, with no significant differences for both materials. Likewise, we detected a drop in ALP levels that was significant for both components between days 4 and 7 of the study (p < 0.05). Electron microscopy images revealed good adhesion capacity to the material, as well as cell differentiation against both types of discs. CONCLUSIONS: The TiNbTa alloy as a material for bone implants offers good osseointegrative capacity, in addition to solving biomechanical problems that pure titanium presents as a component

Fracture resistance after implantoplasty in three implant-abutment connection designs

BACKGROUND: To assess the effect of implantoplasty and implant-abutment design on the fracture resistance and macroscopic morphology of narrow-diameter (3.5 mm) dental implants. MATERIAL AND METHODS: SCREW-shaped titanium dental implants (n = 48) were studied in vitro. Three groups (n = 16) were established, based on implant-abutment connection type: external hexagon, internal hexagon and conical. Eight implants from each group were subjected to an implantoplasty procedure; the remaining 8 implants served as controls. Implant wall thickness was recorded. All samples were subjected to a static strength test. RESULTS: The mean wall thickness reductions varied between 106.46 and 153.75 μm. The mean fracture strengths for the control and test groups were, respectively, 1211.90 ± 89.95 N and 873.11 ± 92.37 N in the external hexagon implants; 918.41 ± 97.19 N and 661.29 ± 58.03 N in the internal hexagon implants; and 1058.67 ± 114.05 N and 747.32 ± 90.05 N in the conical connection implants. Implant wall thickness and fracture resistance (P < 0.001) showed a positive correlation. Fracture strength was influenced by both implantoplasty (P < 0.001) and connection type (P < 0.001). CONCLUSIONS: Implantoplasty in diameter-reduced implants decreases implant wall thickness and fracture resistance, and varies depending on the implant-abutment connection. Internal hexagon and conical connection implants seem to be more prone to fracture after implantoplasty

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Candida albicans biofilms on different materials for manufacturing implant abutments and prostheses

BACKGROUND: Morphological, physical and chemical properties of both implants and prostheses can determine the biofilm formation on their surface and increase the risk of biological complications. The aim of this study was to evaluate the capacity of biofilm formation of Candida albicans on different materials used to manufacture abutments and prostheses. MATERIAL AND METHODS: Biofilm formation was analyzed on cp grade II titanium, cobalt-chromium alloy and zirconia, silicone, acrylic resin (polymethylmethacrylate) and nano-hybrid composite. Some samples were partially covered with lithium disilicate glass ceramic to study specifically the junction areas. C. albicans was incubated in a biofilm reactor at 37 °C with agitation. The biofilm formation was evaluated at 24 and 48 hours. In addition, the morphology of the biofilm was evaluated by scanning electron microscopy. RESULTS: C. albicans developed biofilms on the surface of all materials tested. Cobalt-chromium alloy showed the lowest density of adhered biofilm, followed by zirconia and titanium. Silicone and resin showed up to 20 times higher density of biofilm. A higher biofilm formation was observed when junctions of materials presented micro-pores or imperfections. CONCLUSIONS: The biofilm formed in the three materials used in the manufacture of abutments and prostheses showed no major differences, being far less dense than in the resins. Two clinical recommendations can be made: to avoid the presence of resins in the subgingival area of implant prostheses and to design prostheses placing cobalt-chromium alloy/ceramic or titanium/ceramic junctions as far as possible from implants

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Estudio comparativo de la conformación obtenida con TruNatomy, WaveOne Gold y ProTaper Gold en conductos curvos simulados / Comparative study of the shaping ability obtained with TruNatomy, Wave One Gold and ProTaper Gold systems in simulated curved canals

OBJETIVO: El objetivo del presente estudio fue evaluar la conformación obtenida por los sistemas TruNatomy, WaveOne Gold y ProTaper Gold en conductos curvos simulados de Endo Training Blocks. MATERIALES Y MÉTODOS: Se utilizaron 30 Endo Training Blocks con conductos curvos simulados divididos en 3 grupos de 10 muestras cada uno, instrumentados con TruNatomy, WaveOne Gold y ProTaper Gold respectivamente. Todos los sistemas se emplearon siguiendo el protocolo sugerido por el fabricante. Los conductos simulados se irrigaron con 3 ml de agua destilada a cada cambio de instrumento y al finalizar la preparación. Se utilizó para este procedimiento la aguja plástica del sistema TruNatomy. Las muestras fueron teñidas con tinta china a fin de poder visualizar correctamente el espacio conformado. A continuación, se realiza-ron mediciones del ancho de los conductos curvos simulados a 7 mm, 11 mm y 14 mm del acceso coronal con un software de imágenes. Para la evaluación estadística se llevó a cabo el análisis de variancia de medidas repetidas y la prueba de Tukey. RESULTADOS: Se observaron diferencias estadísticamente significativas entre el grupo de TruNatomy y los otro dos. Las diferencias fueron significativas entre los tercios de cada grupo (P < 0.05). CONCLUSIÓN: El uso del sistema TruNatomy genera una conformación más conservadora que el WaveOne Gold y Protaper Gold en los tres tercios del conducto simulado

OBJECTIVE: The aim of this study was to evaluate the shaping ability performed by TruNatomy, WaveOne Gold and ProTaper Gold systems in simulated curved canals of Endo Training Blocks. MATERIALS AND METHODS: Thirty Endo Training Blocks with simulated curved canals were used. After dividing into 3 groups of 10 samples each, blocks were instrumented with TruNatomy, WaveOne Gold and ProTaper Gold respectively. All systems were used following the protocol suggested by the manufacturer. The canals were irrigated with 3 ml of distilled water between each instrument and as a final rinse. The TruNatomy plastic needle was used for this procedure. The samples were dyed with Chinese ink in order to visualize the final shape. The wide measurements of the simulated curved canals were carried out at 7 mm, 11 mm and 14 mm of the coronal access using image software. For the statistical evaluation the analysis of variance of repeated measures and the Tukey test were done. RESULTS: Statistically significant differences were observed be-tween the TruNatomy group and the other two. The differences were significant between thirds of each group (P < 0.05). CONCLUSIONS: The use of the TruNatomy system generates a more conservative shape than the WaveOne Gold and ProTaper Gold in the three thirds of the simulated canals

A zinc-doped endodontic cement facilitates functional mineralization and stress dissipation at the dentin surface

BACKGROUND: The purpose of this study was to evaluate nanohardness and viscoelastic behavior of dentin surfaces treated with two canal sealer cements for dentin remineralization. MATERIAL AND METHODS: Dentin surfaces were subjected to: I) 37% phosphoric acid (PA) or II) 0.5 M ethylenediaminetetraacetic acid (EDTA) conditioning prior to the application of two experimental hydroxyapatite-based cements, containing sodium hydroxide (calcypatite) or zinc oxide (oxipatite), respectively. Samples were stored in simulated body fluid during 24 h or 21 d. The intertubular and peritubular dentin were evaluated using a nanoindenter to assess nanohardness (Hi). The load/displacement responses were used for the nano-dynamic mechanical analysis to estimate complex modulus (E*) and tan delta (δ). The modulus mapping was obtained by imposing a quasistatic force setpoint to which a sinusoidal force was superimposed. AFM imaging and FESEM analysis were performed. RESULTS: After 21 d of storage, dentin surfaces treated with EDTA+calcypatite, PA+calcypatite and EDTA+oxipatite showed viscoelastic discrepancies between peritubular and intertubular dentin, meaning a risk for cracking and breakdown of the surface. At both 24 h and 21 d, tan δ values at intertubular dentin treated with the four treatments performed similar. At 21 d time point, intertubular dentin treated with PA+oxipatite achieved the highest complex modulus and nanohardness, i.e., highest resistance to deformation and functional mineralization, among groups. CONCLUSIONS: Intertubular and peritubular dentin treated with PA+oxipatite showed similar values of tan δ after 21 d of storage. This produced a favorable dissipation of energy with minimal energy concentration, preserving the structural integrity at the dentin surface

Catéteres y stents urinarios biodegradables. ¿Para cuándo? / Biodegradable catheters and urinary stents. When?

Una de los principales anhelos en el campo de los catéteres y stents urinarios es dotarlos de características biodegradables. Ya que se entiende como un fracaso de estos dispositivos la necesidad de retirada, el síndrome de catéter olvidado, así como los efectos adversos que provocan los dispositivos permanentes tras cumplir su finalidad. Los esfuerzos centrados en nuevos diseños, recubrimientos, así como biomateriales buscan incrementar la biocompatibilidad de estos dispositivos internos. En los últimos tiempos los principales retos con respecto a los dispositivos biodegradables ureterales han avanzado en la correcta dirección. Así, la tasa de degradación se ha conseguido modular gracias a los nuevos biomateriales y al empleo de copolímeros que permiten elegir el tiempo de permanencia al igual que se programa con los catéteres doble jota convencionales. La biocompatibilidad ha mejorado de la mano de nuevos polímeros que se adaptan mejor al medio urinario. Por último uno de los principales problemas, la eliminación de fragmentos degradados, demuestra a nivel experimental que con nuevos diseños que provocan la degradación controlada, de distal a proximal, empleando el trenzado y combinando copolímeros, la degradación se puede provocar por dilución, reduciendo la fragmentación a los últimos estadios de vida de la prótesis. Además se demuestra que potencialmente los catéteres biodegradables pueden provocar menor infección urinaria, menor incrustación y previsiblemente disminuirán la morbilidad de los catéteres, ya que su proceso de degradación reduce los efectos adversos. Con respecto al desarrollo de stents uretrales biodegradables se necesita encontrar biomateriales que permitan mantener sus propiedades biomecánicas a largo plazo, manteniendo la luz uretral abierta tanto en pacientes con HBP como en los casos de estenosis uretral. Se ha conseguido modular el tiempo de degradación de las prótesis, pero todavía la aparición de hiperplasia urotelial polipoidea es una constante en las fases iniciales post-implantación. El desarrollo de stents liberadores de fármaco, antiinflamatorio o antiproliferativos, al igual que stents biodegradables biorrecubiertos es un campo del que se espera venga la solución a estos efectos adversos. Son por tanto muchos aspectos que deben ser mejorados para obtener los ansiados stents biodegradables, pero en los últimos años se han ido cumpliendo hitos, gracias a los avances en Bioingeniería, que permiten vislumbrar en un futuro próximo soluciones seguras y eficaces

One of the main wishes in the field of urinary catheters and stents is to arm them with biodegradable characteristics because we consider a failure of these devices the need for retrieval, the forgotten catheter syndrome as well as the adverse effects permanent devices cause after fulfilling their aim. The efforts focused in new designs, coatings and biomaterials aim to increase the biocompatibility of theses internal devices. Lately, there have been correct advances to answer the main challenges regarding biodegradable ureteral devices. Thus, modulation of the rate of degradation has been achieved thanks to new biomaterials and the use of copolymers that enable to choose the time of permanence as it is programmed with conventional double J catheters. Biocompatibility has improved with the use of new polymers that adapt better to the urine. Finally, one of the main problems is elimination of degraded fragments and experimentally it has be demonstrated that new designs elicit controlled degradation, from distal to proximal; using stranding and combination of copolymers degradation may be caused by dilution, reducing fragmentation to the last stages of life of the prosthesis. Moreover, it has been demonstrated that biodegradable catheters potentially may cause less urinary tract infection, less encrustation and predictably they will diminish catheter morbidity, since their degradation process reduces adverse effects. Regarding the development of biodegradable urethral stents, it is necessary to find biomaterials that enable maintaining their biomechanical properties in the long term, keeping open the urethral lumen both in patients with BPH and urethral stenosis. Modulation of the time of degradation of the prosthesis has been achieved, but the appearance of urothelial hyperplasia is still a constant in the initial phases after implantation. The development of drug eluting stents, anti-proliferative or anti-inflammatory, as well as biodegradable stents biocoated is a field from which it is expected the arrival of the solution of theses adverse effects. Therefore, many features need to be improved to obtain biodegradable stents, but over the last years some turning points have been accomplished thanks to the advances in Bioengineering, allowing to foresee safe and effective solutions in the nearest future

Development and evaluation of isoniazid loaded silk fibroin microsphere / Desarrollo y evaluación de microesfera de seda Fibroin cargado de isoniacida

Aim: Current experimental investigation is dedicated to prepare microspheres with small size and good sphericity by Phase Separation method using Isoniazid (INH) as model drug. Silk fibroin has unique intrinsic qualities like biodegradability, biocompatibility or release properties and their tunable drug loading capacity. The delivery loading proficiency of the drug molecules in silk spheres be contingent on their charge, and hydrophobicity or subsequent in altered drug release profiles. Methods: In the present work Isoniazid loaded silk fibroin microsphere was prepared by using phase separation method. Microsphere was evaluated for Ultraviolet-visible spectroscopy, Fourier Transform infrared spectroscopy, Entrapment efficiency, Scanning electron microscopy Studies. Results: Scanning electron microscopy studies revealed that Isoniazid Loaded Silk Fibroin Microspheres were spherical. Entrapment Efficiency of Isoniazid loaded Microspheres of different Formulation from F1 to F5 was in range of 53 to 68 %. F3 showed 68.47 % entrapment Efficiency and the optimized formulation drug release was 93.56 % at 24 hours. Conclusion: Experimental report disclosed a new aqueous based formulation method for silk spheres with controllable shape or size and sphere. Isoniazid loaded silk microspheres may act as ideal nano formulation with elaborated studies

Objetivo: La investigación experimental en curso está dedicada a la preparación de microesferas de pequeño tamaño y buena esfericidad mediante el método de separación de fases con isoniazida (INH) como fármaco modélo. La fibroina de seda tiene cualidades intrínsecas únicas como la biodegradabilidad, biocompatibilidad o propiedades de liberación y su capacidad de carga de fármacos ajustable. La aptitud de entrega de carga de las moléculas de fármaco en las esferas de seda estar supeditada a su carga, y la hidrofobicidad o subsiguiente alteración en los perfiles de liberación de fármacos. Métodos: En el presente trabajo la microesfera de fibroina de seda cargada de isoniazida fue preparada utilizando el método de separación de fases. La microesfera fue evaluada por espectroscopia ultravioleta-visible, espectroscopia infrarroja con transformado de Fourier, se midió la eficiencia de atrapamiento y se estudios mediante microscopia electrónica de barrido. Resultados: Estudios con el microscopio de escaneo de electrones revelaron que las microesferas de fibroina cargada de isoniazida eran esféricas. La eficacia de atrapamiento de las microesferas de formulación diferente de F1 a F5 estuvo en el rango de 53 a 68 %. F3 mostró un 68,47 % de eficiencia de atrapamiento y tras optimizar la formulación de liberación de fármacos fue de 93,56 %, a las 24 horas

In vitro preliminary study of osteoblast response to surface roughness of titanium discs and topical application of melatonin

OBJECTIVES: To observe human osteoblast behavior cultured in vitro on titanium discs (Ti) in relation to surface roughness and melatonin application. Study DESIGN: Human osteoblasts (MG-63) were cultured on 60 Ti6Al4V discs divided into three groups: GroupI: discs treated with dual acid etching; Group II dual acid etching and blasting with calcium phosphate particles; Group III (control) machined discs. Surface roughness and topography of the discs were examined with scanning electron microscope (SEM) and confocal laser scanning electron microscope( CLSM).Osteoblast adhesion, proliferation and cell morphology were determined by means of fluorescence microscopy with Image-Pro Plus software and SEM. RESULTS: Group II presented the roughest discs, while the least rough were Group III. Cell adhesion was greatest in Group II. The addition of melatonin improved cell proliferation. CONCLUSIONS: 1. Surface treatments (dual acid etching, calcium phosphate impaction) increase surface roughness in comparison with machined titanium.2. Greater surface roughness tends to favor cell adhesion after 24-hour cell culture.3. The addition of melatonin tends to favor osteoblast proliferation

Nuevos biomateriales: estudio in vivo del carburo de silicio como material osteointegrador / New biomaterials: in vivo study of silicon carbide as boneintegration material

Objetivo: Evaluar, mediante ensayos in vivo, la biocompatibilidad y el grado de penetración ósea en la microestructura porosa del carburo de silicio (SiC). Material y métodos: se implantaron en cóndilos femorales de conejos cilindros de SiC obtenidos a partir de maderas de pino y sapeli. Como material de referencia fueron utilizados cilindros de titanio. El sacrificio de los animales se realizó a las 12 semanas de implantación y se procedió al examen histológico de las muestras. Resultados: Comprobamos un crecimiento de trabéculas óseas, tanto en la superficie del implante como a través de su estructura porosa, sin apreciarse signos de inflamación ni aparición de tejido fibroso alrededor de la muestra. Estos resultados son confirmados mediante microscopía electrónica de barrido (SEM) y análisis de rayos X por dispersión de energías. Conclusión: El carburo de silicio biomórfico es una cerámica con excelentes propiedades mecánicas y porosidad interconectada que le confiere un especial atractivo de cara a sus aplicaciones biomédicas en implantes ortopédicos (AU)

Objective: To evaluate, using in vivo tests, the biocompatibility and the degree of bone penetration into the porous microstructure of silicon carbide (SiC). Material and methods: For this purpose cylindres of SiC obatained from wood of pine and sapeli were implanted in femoral condyles of rabbits. As reference material we used titanium cylinders. The slaughter of animals was performed at 12 weeks of implantation and proceeded to the histological examination of the samples. Results: We see a growth of bone trabeculae, both on the surface of the implant and through its porous structure, without signs of inflammation or appearance of fibrous tissue around the samples. These results are confirmed by scanning electron microscopy scanning (SEM) and X-ray analysis by dispersion of energies (EDS). Conclusion: Biomorphic silicon carbide (SiC) is a ceramic with excellent mechanical properties and interconnected porosity which gives a special attraction for their biomedical applications in orthopaedic implants (AU)

El níquel y su vínculo con el agrandamiento gingival: Revisión de la literatura / Relationship of nickel and gingival enlargement: Review of the literature

El agrandamiento gingival es común entre los pacientes y puede ser causado por una variedad de factores etiológicos. La razón más común es la inflamación gingival provocada por mala higiene oral y alta carga bacteriana. Otros factores implicados son los medicamentos sistémicos, en donde se encuentran bloqueadores de los canales de calcio, inmunosupresores y anticonvulsivantes. Algunos crecimientos gingivales podrían estar asociados a condiciones hormonales como la pubertad, el embarazo o la diabetes o ser un síntoma de una enfermedad sistémica y en raras ocasiones el agrandamiento gingival se asocia a factores genéticos y hereditario llamado fibromatosis gingival. Otra causa del agrandamiento gingival se viene presentando en la consulta odontológica y es la relacionada con la aparatología ortodóncica fija, cuya causa específica no está totalmente definida aún. El presente artículo es una revisión narrativa cuyo objetivo es describir las generalidades del agrandamiento gingival y reportes en la literatura sobre la acción de la aparatología ortodóncica fija en el agrandamiento gingival, pues se presume del níquel como otro factor causal de esta patología

Gingival overgrowth is common among patients and can be caused by a variety of etiological factors. The most common reason is gingival inflammation caused by poor oral hygiene and high bacterial load. Other factors include systemic drugs, like channel blockers are calcium, immunosuppressants and anticonvulsants. Some gingival overgrowth are associated with hormonal conditions such as puberty, pregnancy or diabetes or be a symptom of a systemic disease and rarely the gingival overgrowth is associated with genetic factors, who is called hereditary gingival fibromatosis. Another cause of gingival overgrowth has been presented in dentistry and is related to fixed orthodontic appliances, whose specific cause is not fully defined yet. This article is a narrative review which aims to describe the generalities of gingival overgrowth and reports in the literature of the effect of fixed orthodontic appliances in gingival overgrowth because nickel probably is another factor causing this condition

The cytotoxic evaluation of mineral trioxide aggregate and bioaggregate in the subcutaneous connective tissue of rats

Objectives: The purpose of this study was to evaluate and compare the cytotoxic effects of ProRoot MTA and DiaRoot BA, a bioceramic nanoparticulate cement, on subcutaneous rat tissue. Study Design: Fifty Sprouge Dawley rats were used in this study. Polyethylene tubes filled with ProRoot MTA and DiaRoot BioAggregate, along with a control group of empty, were implanted into dorsal connective tissue of rats for 7, 15, 30, 60, and 90 days. After estimated time intervals the rats were sacrificed. The specimens were fixed, stained with hematoxylin and eosin, and then evaluated under a light microscope for inflammatory reactions and mineralization. Results: All groups evoked a severe to moderate chronic inflammatory reaction at 7 and 15 days, which decreased with time. Both the MTA and BioAggregate groups showed similar inflammatory reactions, except at 90 days when MTA showed statistically significant greater inflammation (p>0.05). The MTA group showed foreign body reaction at all times. Compared to BioAggregate, MTA showed significantly more foreign body reaction at 60 and 90 days (p<0.0001). After 30 days foreign body reaction of BioAggregate decreased significantly. Both MTA and BioAggregate groups showed similar necrosis at 7 and 15 days (p=0.094 and p=0.186 respectively). No necrosis was observed after 15 days. Similarly there was no fibrosis after 30 days for both MTA and BioAggregate groups (p>0.05). Conclusions: Since DiaRoot BioAggregate showed significantly better results than MTA, we can conclude that it is more biocompatible. However, further studies are required to confirm this result (AU)

Estudio comparativo de biocompatibilidad entre la hemodiafiltración en línea y la hemodiafiltración con reinfusión endógena / Biocompatibility comparative study between online hemodiafiltration and hemodiafiltration with endogenous reinfusion

Objetivo: Comparar la biocompatibilidad entre la hemodiafiltración en línea (HDF) y la hemodiafiltración con reinfusión endógena (HFR). Material y método: Estudio comparativo observacional en una población de 15 pacientes en hemodiálisis crónica elegidos al azar entre los pacientes de nuestra unidad. Se compararon cambios en el perfil hematológico, nivel de PCR y constantes vitales, pre y post hemodiálisis, tras someterse a ambas técnicas de hemodiafiltración. Se comparó las diferencias entre los parámetros estudiados pre y post hemodiálisis en cada técnica. Resultados: Los niveles de plaquetas descendieron más en la HDF (HDF -1,33 vs HFR -19,73 x103/mm3, p=0,005). El nivel de leucocitos disminuyó en la HDF y aumentó en la HFR (HDF -0,46 vs HFR +0,8 x103/ mm3; p=0,006). Respecto a la fórmula leucocitaria hubo resultados dispares: segmentados HDF -1,7 vs HFR +5,4%, p<0,001; linfocitos HDF +1,96 vs HFR -3,62%, p<0,001. Con la HFR disminuyeron menos los niveles de PCR (HDF -0,05 vs HFR -0,001 mg/ dl; p=NS). En lo referente a las constantes vitales, la tensión arterial sistólica descendió más en la HFR que en la HDF (HDF -9,93 vs HFR -10,33 mmHg; p<0,001), a la inversa que la diastólica (HDF -5,2 vs HFR -3 mmHg; p=0,007) y la frecuencia cardiaca (HDF -1,46 vs HFR +1,73 lpm; p=NS). La temperatura corporal aumentó más con la HDF que con la HFR (HDF +0,35 vs HFR +0,06 ºC; p=NS). Conclusiones: Según nuestros resultados la HFR parece más biocompatible que la HDF, probablemente derivado por la reinfusión exógena de la HDF (AU)

Aim: To compare biocompatibility between online hemodiafiltration (HDF) and hemodiafiltration with endogenous reinfusion. Methods: Observational comparative study in a population of 15 chronic hemodialysis patients randomly selected among the patients in our unit. We compared changes in hematological profile, CRP level and vital signs, pre and post hemodialysis, after undergoing both hemodiafiltration techniques. Comparing the differences between the parameters studied before and after each hemodialysis technique. Results: Platelet levels decreased more in the HDF (HDF -1,33 vs HFR -19,73 x103/mm3, p=0,005). Leukocyte levels decreased in the HDF and increased with HFR (HDF -0,46 vs HFR +0,8 x103/mm3; p=0,006). Regarding the leukocyte formula had mixed results: segmented HDF -1,7 vs HFR +5,4%, p<0,001; lymphocytes HDF +1,96 vs HFR -3,62%, p<0,001. With the HFR decreased CRP levels less (HDF -0,05 vs HFR -0,001 mg/dl; p= NS). Regarding vital signs, systolic blood pressure decreased more in the HFR than HDF (HDF -9,93 vs HFR -10,33 mmHg; p<0,001), conversely that the diastolic blood pressure (HDF -5,2 vs HFR -3 mmHg; p=0,007), and heart rate (HDF -1,46 vs HFR +1,73 lpm; p=NS). Body temperature increased more with the HDF that the HFR (HDF +0,35 vs HFR +0,06 ºC; p=NS). Conclusions: According to our results the HFR seems more biocompatible than the HDF, probably derived by exogenous reinfusion of HDF (AU)

Pectina: Usos Farmacéuticos y Aplicaciones Terapéuticas / Pectin: Pharmaceutical and Therapeutic Uses

La pectina es un polisacárido de origen vegetal que posee excelentes características de gelificación, y biocompatibilidad, por lo que ha sido ampliamente estudiada como excipiente en diversas formas farmacéuticas para modular la liberación de moléculas activas. La pectina permanece intacta en la parte alta del tracto gastrointestinal, y sólo es degradada por la microflora del colon. Por tal motivo, se ha incluido en esta revisión el desarrollo de diferentes formulaciones de liberación colónica de fármacos basadas en este polisacárido para tratar afecciones locales como el cáncer de colon y la enfermedad de Crohn. También se incluyen diversos estudios acerca de aplicaciones terapéuticas de la pectina como coadyuvante en diferentes patologías digestivas como el reflujo gastroesofágico y la diarrea persistente. El efecto que, sobre los niveles de glucosa, insulina y lípidos en plasma, puede tener una dieta rica en pectina es así mismo analizado(AU)

Pectin: Pharmaceutical and Therapeutic UsesPectin is a polysaccharide of vegetarian origin, combining both excellent gelation and biocompatibility characteristics, and thus has been widely studied as an excipient in different pharmaceutical forms in order to modulate the release of active molecules. Pectin remains intact in the upper gastrointestinal tract and only gets degraded by colonic microflora. Hence, different formulations based on this polysaccharide, which have been developed to target drugs to the colon and treat local affections like colon cancer and Crohn’s disease, were included in this review. Also, different studies on therapeutic uses of pectin as an adjuvant in various digestive pathologies such as the gastro-esophageal reflux and persistent diarrhea have been discussed. The effects of a rich pectin-diet over the glucose, insulin and lipid plasma levels are also commented(AU)

Comparison of two histopathologic methods for evaluating subcutaneous reaction to mineral trioxide aggregate

Objectives: One of the most important factors for suitable materials for pulp therapy is biocompatibility. Two histopathologic methods of Cox and Federation Dentaire International (FDI) were used to evaluate inflammation. In Cox method, density of inflammatory cells, tissue reactions like fibrosis, vascular responses like congestion and fibrin extravasation have been used to evaluate inflammatory reactions. The aim of this study was to compare the accuracy of pathologists’ interpretations using two different methods. Study design: Three pathologists observed the degree of inflammation in 225 histopathologic sections. These sections showed inflammation in subcutaneous connective tissue of rats adjacent to polyethylene tubes, filled with white or gray mineral trioxide aggregate. Empty tubes served as controls. Samples were harvested after 7-, 15-,30-, 60-, and 90-days. All pathologists examined the sections under a light microscope (Carl Zeiss, Oberkochen,Germany) at ×400 magnifications. Chi-Square test was used to evaluate the difference between inflammation grades when one pathologist used two methods. Cohen’s Kappa value was used to measure agreement of three pathologists to recognize the degrees of inflammations when using one of the methods(..) (AU)

Suture needles in Oral Surgery: Alterations depending on the type and number of sutures

This study examined whether the number and type of sutures used in oral surgery influence two ad hoc variables(incision plane and displaced area), which are two variables related to whether the suture needle is suitable for the task. Seventy-five TB-15 needles were studied, which were used to suture between zero and three mucosa and/subperiosteal sutures, producing 15 groups with 5 needles in each one. The incision plane and displaced area were measured for each group, which are two variables related to how the needle has worn and altered. Statistical treatment was conducted using the Kruskal-Wallis H test to compare multiple values and the Mann-Whitney Utest to compare pairs. A multi-stage regression model was applied with the aim of predicting the changes in the dependent variables based on the number and type of sutures performed. The incision plane ranged from 126.67 to346.24ìm among the different groups. The displaced area was measured as being between 14 524.83ìm² and 128311.91ìm². The best predictive model for the incision plane obtained a coefficient of determination (R2) of 0.149,while it reached 0.249 for the displaced area. Subperiosteal sutures held more weighting among the variables studied. Mucosal sutures did not seem to greatly affect needle wear. Observations reported in this paper indicate that the needle should be changed after having performed two subperiosteal sutures, given the wear and change to the incision plane that is produced, which causes the needle’s cutting ability to reduce (AU)