Estudio de la fuerza de adhesión de brackets metálicos y cerámicos sobre superficies de zircona tratadas con láser de femtosegundos

Objetivos: 1) Analizar los estudios publicados sobre los efectos de diferentes láseres en la adhesión a superficies de cerámica; 2) determinar los parámetros ideales del láser de femtosegundos para conseguir una adhesión óptima bracket-zircona; 3) analizar los efectos del láser de femtosegundos en la fuerza de adhesión de brackets metálicos y cerámicos sobre zircona; comparar la fuerza de adhesión entre brackets cerámicos y metálicos a zircona. Material y métodos: El trabajo se dividió en tres partes. 1.Revisión sistemática de la literatura y meta-análisis para determinar qué tipo de láser es el más efectivo para adherir cementos y composites sobre superficies de cerámica. 2.Estudio in-vitro para determinar los parámetros ideales del láser de femtosegundos para una adhesión óptima de brackets a superficies de zircona. 180 láminas de zircona se asignaron a 6 grupos según tratamiento de superficie a aplicar: [1] control, [2] abrasión con partículas de alúmina (APA), [3] irradiación mediante láser de femtosegundos (FS) a 300mW de potencia y separación inter-surco de 60um, [4] FS 200mW, 100um, [5] FS 40 mW, 60 um, y [6] FS 200mW, 60um. Se cementaron brackets metálicos sobre las superficies y se midió la fuerza de adhesión aplicando el test de resistencia a la fuerza de cizalla utilizando una máquina de pruebas universal. 3. Estudio in-vitro para analizar los efectos del láser de femtosegundos sobre la fuerza de adhesión de brackets cerámicos y metálicos a superficies de zircona. 300 láminas de zircona se dividieron en 5 grupos según el tratamiento de superficie a aplicar: [1] control, [2] APA, [3] silicatización, [4] FS, y [5] APA+FS. Cada grupo se dividió en dos subgrupos (brackets metálicos vs cerámicos) y se midió la fuerza de adhesión de la misma manera que en la segunda parte del estudio. Resultados: 1. Se incluyeron 52 artículos en la revisión sistemática y 25 en el meta-análisis. Los láseres aumentaban la fuerza de adhesión cuando se compararon con grupos control. 2. Se obtuvieron fuerzas de adhesión significativamente más altas para los grupos 3 y 6 que para el resto. 3. Las fuerzas de adhesión fueron más altas para los brackets cerámicos que para los metálicos en todos los grupos. Los grupos tratados mediante silicatización, FS y APA+FS obtuvieron fuerzas de adhesión significativamente mayores que los otros grupos para brackets metálicos. Para brackets cerámicos, los valores de adhesión más altos se obtuvieron para APA, FS y APA+FS. Conclusiones: Los láseres como tratamiento de las superficies de cerámica mejoran su adhesión a cementos y composites. Es necesario estandarizar los protocolos experimentales y establecer parámetros ideales para cada láser. El láser de femtosegundos a 300mW y 60um proporciona los valores más altos de adhesión bracket-zircona. Se proponen los parámetros del láser de femtosegundos de 200mW y 60um como los ideales para una adhesión óptima bracket-zircona, descartando los 300mW por su alto consumo energético. El láser de femtosegundos potencia la adhesión de brackets cerámicos y metálicos sobre zircona. Los brackets cerámicos proporcionan fuerzas de adhesión más altas sobre zircona que los metálicos independientemente del método de acondicionamiento de la superficie

Estudio de asociaciones nanopartículas de plata con medios biológicos mediante electroforesis en gel y detección por Ablación Láser-ICP-MS

Cuando las nanopartículas de plata (AgNPs) entran en contacto con un fluido biológico tienden a unirse a moléculas presentes en el medio, en concreto, al entrar en contacto con la sangre se unen a proteínas, formando proteínas corona (PC). En este trabajo se quiere estudiar cómo afecta la funcionalización de las AgNPs en su afinidad para adsorberse a proteínas mayoritarias del plasma sanguíneo. En el presente trabajo se han usado tres tipos de AgNPs con distintos recubrimientos: citratos, polivinilpirrolidona (PVP) y polietilenglicol (PEG). Las proteínas utilizadas han sido albúmina de suero bovino y transferrina humana por ser las más abundantes en el plasma sanguíneo. Se realizaron incubaciones de AgNPs con proteínas, a un pH de 7,4 que es al que se encuentra la sangre y a 37 ˚C para simular la temperatura a la que se encuentra el cuerpo humano. Para llevar a cabo el estudio se han usado distintas técnicas, en primer lugar se ha usado la espectrometría de absorción molecular ultravioleta - visible (EAM-UV-Vis) y la electroforesis en gel de poliacrilamida (PAGE) para evaluar cualitativamente si se formaban PC. Tras comprobar que sí se formaban PC, se llevo a cabo el método Bradford, también haciendo uso de la EAM-UV-Vis, para cuantificar el porcentaje de AgNPs que pasaban a formar parte de PC. También se realizaron electroforesis en gel de agarosa (AGE) y posteriormente las AgNPs y PC separadas en el gel se detectaron mediante ablación láser e ICP-MS. Por último se evaluó el porcentaje de Ag0 presente en las NPs que pasa a formar Ag (I) en presencia de las proteínas mediante espectrometría de masas con plasma de acoplamiento inductivo (ICP-MS)

Approaches to the Synthesis of 2,3-Dihaloanilines. Useful Precursors of 4-Functionalized-1H-indoles§

2,3-Dihaloanilines have been proved as useful starting materials for synthesizing 4-halo-1H-indoles. Subsequent or in situ functionalization of the prepared haloindoles allows the access to a wide variety of 2,4- or 2,3,4-regioselectively functionalized indoles in good overall yields. As no efficient synthetic routes to 2,3-dihaloanilines have been described in the literature, different approaches to the preparation of these 1,2,3-functionalized aromatic precursors are now presented. The most general one involves a Smiles rearrangement from the corresponding 2,3-dihalophenols and allows the preparation of 2,3-dihaloanilides in a straightforward and synthetically useful manner.Ministerio de Ciencia e Innovacion (MICINN) and FEDER (CTQ2010-15358) and Junta de Castilla y Leon (BU021A09 and GR-172) for financial support. V.G. thanks Ministerio de Educacion y Ciencia for a MEC-FPU predoctoral fellowship. P.G.-G. and M.A.F.-R. thank MICINN for "Juan de la Cierva" and "Ramon y Cajal" contracts.This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of organic chemistry, copyright © American Chemical Society after peer review and technical editing by the publisher

Antibacterial Properties of Nanoparticles in Dental Restorative Materials. A Systematic Review and Meta-Analysis

Background and Objectives: Nanotechnology has become a significant area of research focused mainly on increasing the antibacterial and mechanical properties of dental materials. The aim of the present systematic review and meta-analysis was to examine and quantitatively analyze the current evidence for the addition of different nanoparticles into dental restorative materials, to determine whether their incorporation increases the antibacterial/antimicrobial properties of the materials. Materials and Methods: A literature search was performed in the Pubmed, Scopus, and Embase databases, up to December 2018, following PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) guidelines for systematic reviews and meta-analyses. Results: A total of 624 papers were identified in the initial search. After screening the texts and applying inclusion criteria, only 11 of these were selected for quantitative analysis. The incorporation of nanoparticles led to a significant increase (p-value < 0.01) in the antibacterial capacity of all the dental materials synthesized in comparison with control materials. Conclusions: The incorporation of nanoparticles into dental restorative materials was a favorable option; the antibacterial activity of nanoparticle-modified dental materials was significantly higher compared with the original unmodified materials, TiO2 nanoparticles providing the greatest benefits. However, the high heterogeneity among the articles reviewed points to the need for further research and the application of standardized research protocols

A comparative study of aesthetic perceptions of malocclusion among general practice dentists, orthodontists and the public using a visual analogue scale (VAS) and the IOTN-AC

Perception of malocclusion varies among individuals and among patients and practitioners. Although several indices that tend to coincide in many aspects and unify criteria, no single index has been recognised as the most suitable for assessing orthodontic treatment need. Moreover, orthodontists are not always aware of the differences in perception of malocclusion between patients and practitioners. To examine the perception of dental anaesthetics amongst dentists, orthodontists and the general population, study the relationship between the perception of dental aesthetics and the severity of the malocclusion, using the visual analogue scale and the IOTN-AC, and investigate relationships among the resulting data. Frontal intraoral photographs of 24 cases were classified by the severity of their malocclusion according to the DAI index. The photographs were examined by 150 individuals (30 orthodontists, 30 general dental practitioners and 90 members of the general population), who assessed them on a visual analogue scale and according to the IOTN-AC. The orthodontists gave the lowest scores on the visual analogue scale, although the differences between the three groups were not significant. For DAI grades 1, 3 and 4, significant differences were found in the IOTN-AC assessments. Here too, the orthodontist group was the most critical. In general, in all three groups, both the visual analogue scale and IOTN-AC scores increased or decreased in line with the severity of the malocclusion according to the DAI. However, the correlation between these scores was low. The orthodontists scored the malocclusions more critically than the general dentists or the general population with the IOTN-AC, but this difference was not found with the visual analogue scale

Role of Nutrient and Energy Sensors in the Development of Type 2 Diabetes

Cell survival depends on the constant challenge to match energy demands with nutrient availability. This process is mediated through a highly conserved network of metabolic fuel sensors that orchestrate both a cellular and whole-body energy balance. A mismatch between cellular energy demand and nutrient availability is a key factor in the development of type 2 diabetes, obesity, metabolic syndrome, and other associated pathologies; thus, understanding the fundamental mechanisms by which cells detect nutrient availability and energy demand may lead to the development of new treatments. This chapter reviews the role of the sensor PASK (protein kinase with PAS domain), analyzing its role in the mechanisms of adaptation to nutrient availability and the metabolic response in different organs (liver, hypothalamus) actively cooperating to control food intake, maintain glycaemia homeostasis, and prevent insulin resistance and weight gain

Estudio multidisciplinar de seguimiento del peso corporal en una cohorte de pacientes en tratamiento inicial con antipsicóticos

Introduction. El aumento de peso es una de las reacciones adversas más preocupantes de los antipsicóticos atípicos por el riesgo cardiovascular que entraña, entre otros aspectos. El objetivo principal es conocer la evolución del peso e índice de masa corporal a los 6 meses asociada al tratamiento inicial con antipsicóticos en condiciones reales de uso. Métodos. Estu- dio de cohortes, multicéntrico y prospectivo. Resultados. Se ha reclutado una cohorte de 71 pacientes tratados con antipsicóticos (mediana=54 años). Un 60% de pacientes muestra un incremento de peso al finalizar el periodo de seguimiento. En los hombres (32%, mediana=37 años), se obtuvo que el peso corporal medio inicial fue 74, 9 kg (DE=15,4) y final 81,1 kg (DE=16,7); el índice masa corporal medio inicial 25, 1 kg/m2 (DE=4,2) y final 27,1 kg/m2 (DE=4,6). En las mujeres (68%, mediana=61,5 años), se obtuvo que el peso corporal medio inicial fue 61, 4 kg (DE=10,0) y final 63, 0 kg (DE=11,2); el índice masa corporal medio inicial 26, 6 kg/m2 (DE=4,9) y final 27,0 kg/m2 (DE=4,6). El aumento de 2 o más kg de peso es signi- ficativamente mayor en menores de 55 años, así como en hombres. Conclusiones. El inicio de tratamiento con un antipsicótico en condiciones reales de uso se asocia a incremento de peso e índice de masa corporal de los pacientes a los 6 meses, tanto en hombres como mujeres. Se ha constituído un grupo de investigación multidisciplinar centrado en el estudio del uso de antipsicóticos.Introduction. Weight gain is one of the most troubling adverse effects of atypical anti- psychotics due to their cardiovascular risk and other factors. The main objective is to assess possible changes of body weight and body mass index at 6 months associated with onset of antipsychotic treatment in ordinary clinical use. Methods. It's a cohort, multicentre, prospective study. Results. A cohort of 71 patients treated with antipsychotics was recruited (median=54 years). A total of 60% of patients showed an increase of body weight at the end of the follow- up period. In males (32%, median=37 years), it was obtained that mean body weight at base- line was 74, 9 kg (DE=15,4)and at 6 months 81,1 kg (DE=16,7); mean body mass index at baseline was 25,1 kg/m2 (DE=4,2) and at 6 months 27,1 kg/m2 (DE=4,6). In women (68%, median=61,5 years), it was obtained that mean body weight at baseline was 61,4 kg (DE=10,0) and at 6 months 63, 0 kg (DE=11,2); mean body mass index at baseline 26,6 kg/m2 (DE=4,9) and at 6 months 27,0 kg/m2 (DE=4,6). Increase of body weight over 2 kg was significantly higher in patients under 55 years and males. Conclusions. Onset of antipsychotic treatment in ordinary clinical use is associated with an increase of patients' body weight and body mass index at 6 months, both for men and women. A multidisciplinary research team focused on the study of antipsychotic use of has been established

The effects of lasers on bond strength to ceramic materials: A systematic review and meta-analysis

Lasers have recently been introduced as an alternative means of conditioning dental ceramic surfaces in order to enhance their adhesive strength to cements and other materials. The present systematic review and meta-analysis aimed to review and quantitatively analyze the available literature in order to determine which bond protocols and laser types are the most effective. A search was conducted in the Pubmed, Embase and Scopus databases for papers published up to April 2017. PRISMA guidelines for systematic review and meta-analysis were followed. Fifty-two papers were eligible for inclusion in the review. Twenty-five studies were synthesized quantitatively. Lasers were found to increase bond strength of ceramic surfaces to resin cements and composites when compared with control specimens (p-value < 0.01), whereas no significant differences were found in comparison with air-particle abraded surfaces. High variability can be observed in adhesion values between different analyses, pointing to a need to standardize study protocols and to determine the optimal parameters for each laser type

Changes in the alveolar bone thickness of maxillary incisors after orthodontic treatment involving extractions ? A systematic review and meta-analysis

Orthodontic treatment involving en-masse retraction of incisors following premolar extractions, may induce morphological alterations of the alveolar bone surrounding the anterior teeth. To assess changes in alveolar bone thickness around the incisors of extraction patients measured with CBCT. An electronic search was conducted in PubMed, Scopus, Embase and Cochrane Library, using search terms, with no limitation on publication date, up to April 2018. The articles selected for analysis included randomized controlled trials, case-control studies and cohort studies of patients treated with fixed appliances and premolar extractions, which had measured alveolar bone thickness with CBCT before and after treatment. Changes in bone thickness were calculated and the heterogeneity of the studies was assessed using the I2 and Cochran?s Q tests. Of the 136 articles identified in the initial search, 19 were related to the review subject. After removing a further 14 that did not meet the inclusion criteria, 5 articles were selected for analysis. All five were retrospective studies of medium quality. The main changes in alveolar bone thickness were found in the labial cervical third of the central incisor, presenting increases of 0.4-0.64 mm. On the palatal side the results varied considerably. A significant increase in alveolar bone thickness occurs in the labial cervical third of the central incisor. These changes may be influenced by incisor position and inclination, the orthodontic technique and mechanics employed, the timing of the final CBCT scan and the bone remodeling capacity during en-masse retraction