In-vitro mechanical and biological evaluation of novel zirconia reinforced bioglass scaffolds for bone repair.

Bone defects resulting from infections, tumors, or traumas represent a major health care issue. Tissue engineering has been working togehter with medicine to develop techniques to repair bone damage and increase patient's life quality. In that context, scaffolds composed of bioactive ceramics have been explored, although their poor mechanical properties restrain their clinical applications as highly porous structures. As an alternative solution, this study aimed to evaluate the mechanical properties and biological response of novel zirconia reinforced bioactive glass scaffolds (ZRBG) manufactured by the replica method. The microstructure, chemical composition, compressive strength, density, in-vitro bioactivity, and cell viability were analyzed and compared to scaffolds made of monolithic zirconia of similar architecture (45, 60 and 85 ppi). The microstructure of ZRGB scaffolds consisted of a bioactive glass matrix with dispersed zirconia particles (~33% glassy phase) and the compressive strength values (ZRBG scaffolds: 0.33 ± 0.11, 0.41 ± 0.20 and 0.48 ± 0.6 MPa; ZRBG scaffolds with extra BG coating: 0.38 ± 0.13, 0.45 ± 0.11 and 0.50 ± 0.14 MPa for 45, 60 and 80 ppi, respectively) were not statistically different from those of zirconia scaffolds (0.25 ± 0.14 MPa for 45 ppi, 0.32 ± 0.11 MPa for 60 ppi and 0.44 ± 0.07 MPa for 80 ppi). No bioactivity was exhibited by monolithic zirconia scaffolds while significant bioactive response was found for ZRBG scaffolds. The cell viability of ZRBG scaffolds in osteogenic medium was improved up to 171% over zirconia scaffolds. This work provides promosing results for further exploring this technique for implant dentistry.

Production and characterization of zirconia structures with a porous surface.

The aim of this study was to produce zirconia structures with a porous surface by the dip coating technique and assess the mechanical properties of the structures as well as the integrity of the porous layers. Surface porous layers with homogenous and graded porosity were produced over zirconia substrate discs using zirconia powders with different average sizes (d50 = 40 µm; d50 = 70 µm and d50 = 100 µm) and without pore forming fugitive phases. Specimens were inspected using Scanning Electron Microscopy. Bending strength of specimens was obtained from biaxial flexural tests (B3B). Porous layers were successfully produced on zirconia discs substrates and the bending strength of these specimens were ~35% lower than uncoated specimens. Delamination occurred especially in layers with higher thickness and made of bigger particles. Practical application examples were provided in this paper showing the versatility of these porous surfaces in the production of multifunctional surfaces for stronger interfaces.

Influence of laser structuring of PEEK, PEEK-GF30 and PEEK-CF30 surfaces on the shear bond strength to a resin cement.

OBJECTIVES: The aim of this study was to evaluate the influence of a surface conditioning technique using laser ablation and acid etching on PEEK substrate on its bonding strength to a resin cement. MATERIALS AND METHODS: Cylindrical specimens of unfilled PEEK, 30% glass fiber reinforced PEEK and 30% carbon fiber reinforced PEEK were separated in four groups according to the following surface treatments: acid etching with H2SO4, laser ablation with 200 µm holes spaced 400 µm apart (D2E4), laser ablation with 200 µm holes spaced 600 µm apart (D2E6), and laser ablation (D2E4) followed by acid etching. A dual-curing resin cement (Allcem CORE) was then applied to the PEEK surface. Specimens were aged in distilled water at 37 °C for 24 h. Shear bond strength tests were performed to the fracture of the samples. Two-way ANOVA statistical analysis was performed with a significance level of 0.05. Scanning electron microscopy analysis was performed to analyse the conditioned and fracture surfaces. RESULTS: SEM images of the test interfaces showed that the resin cement could not flow in the holes designed by the laser ablation on the PEEK surface. The shear bond strength of PEEK to resin cement was not improved by the surface modification of the PEEK. Also, there was a statistically significant decrease in shear bond strength for unfilled PEEK specimens. On carbon or glass reinforced PEEK, the change was not significant. SEM images of the fracture surfaces revealed that the failure mode was mainly adhesive. CONCLUSIONS: Although laser ablation promoted the PEEK surface modification by the formation of retentive holes, the test resin cement could not thoroughly flow on the rough modified surfaces to establish an effective mechanical interlocking. That negatively affected the shear bonding strength of PEEK to the resin cement. Further studies should be carried out to increase the bonding between PEEK and resin cements.

Bond strength enhancement of zirconia-porcelain interfaces via Nd:YAG laser surface structuring.

OBJECTIVES: The aim of this study was to evaluate the effect of laser surface structuring on the bond strength of feldspar-based porcelain to zirconia, as compared to conventional sandblasting treatment. MATERIALS AND METHODS: Thirty cylindrical zirconia substrates, previously sintered, were divided in three groups according to the type of surface conditioning: 1) sandblasting with 50 µm Al2O3; 2) laser structuring (Ø25 µm holes); and 3) laser structuring (Ø50 µm holes). Porcelain was injected onto the zirconia substrates. X-ray diffractometry (XRD) was used to evaluate the influence of the laser treatment on zirconia crystallographic phases. Shear bond strength test was performed. Micrographs using SEM were used to evaluate the zirconia surface after each surface treatment and to evaluate the fracture surface after the shear test. RESULTS: The laser-structured groups presented the highest shear bond strength (65 ±â€¯16 MPa and 65 ±â€¯11 MPa, for the 25 µm and 50 µm holes, respectively). The sandblasting samples presented shear bond strength of 37 ±â€¯16 MPa. XRD analysis showed that there was no phase transformation on the thermally affected surface due to laser action. Microcracks were created at some holes due to the high temperature gradient generated by laser. SIGNIFICANCE: Laser structuring significantly increased (up to 75%) the shear bond strength of zirconia to veneering porcelain as compared to conventional sandblasting treatment. Therefore, laser structuring arises as a surface conditioning method for producing stronger and long lasting zirconia-porcelain interfaces.

Mesoporous bioactive glass embedding propolis and cranberry antibiofilm compounds.

The aim of this study was to evaluate the chemical reactivity of 58S mesoporous bioactive glass (MBG) particles in as-synthesized condition and after embedding propolis and cranberry antibiofilm compounds at different concentrations. MBG 58S was synthesized by alkali sol-gel method with the addition of the triblock pluronic copolymer P123 as surfactant. Samples were characterized by physicochemical properties measurement, N2 adsorption/desorption analysis, and field emission gun scanning electron microscopy (FEGSEM) observations. MBG powders were immersed into 5 and 10 µg/mL propolis or cranberry solutions for 24 h. The chemical reactivity of the specimens was evaluated by FEGSEM, EDX, FTIR, Ca/P ratio, XRD, and sample weight gain analysis after being immersed in simulated body fluid (SBF) for 8, 24, and 72 h. MBG particles exhibited the expected chemical composition with a particle size distribution ranging from 1.44 to 955 µm, and a mean particle size of 154 µm. MBG particles exhibited a pore volume of 0.8 cc/g, pore radius of ∼2 nm, and surface area of 350.2 m2 /g, according to BJH and BET analyses. A hydroxyl-carbonate apatite (HCAp) layer was formed on all samples after SBF immersion for 72 h. Pure MBG showed the highest chemical reactivity after 72 h, with the resulting apatite layer exhibiting a Ca/P ratio of ∼1.6 in accordance to stoichiometric biological apatite. MBG embedding propolis and cranberry can be considered for future microbiological analysis since the presence of propolis or cranberry did not interfere with MBG's ability to develop a HCAp layer, which is an essential feature for bone regeneration applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1614-1625, 2018.

THERMAL RESIDUAL STRESSES IN BILAYERED, TRILAYERED AND GRADED DENTAL CERAMICS.

Layered ceramic systems are usually hit by residual thermal stresses created during cooling from high processing temperature. The purpose of this study was to determine the thermal residual stresses at different ceramic multi-layered systems and evaluate their influence on the bending stress distribution. Finite elements method was used to evaluate the residual stresses in zirconia-porcelain and alumina-porcelain multi-layered discs and to simulate the 'piston-on-ring' test. Temperature-dependent material properties were used. Three different multi-layered designs were simulated: a conventional bilayered design; a trilayered design, with an intermediate composite layer with constant composition; and a graded design, with an intermediate layer with gradation of properties. Parameters such as the interlayer thickness and composition profiles were varied in the study. Alumina-porcelain discs present smaller residual stress than the zirconia-porcelain discs, regardless of the type of design. The homogeneous interlayer can yield a reduction of ~40% in thermal stress relative to bilayered systems. Thinner interlayers favoured the formation of lower thermal stresses. The graded discs showed the lowest thermal stresses for a gradation profile given by power law function with p=2. The bending stresses were significantly affected by the thermal stresses in the discs. The risk of failure for all-ceramic dental restorative systems can be significantly reduced by using trilayered systems (homogenous or graded interlayer) with the proper design.

Influence of interlayer design on residual thermal stresses in trilayered and graded all-ceramic restorations.

Residual thermal stresses are formed in dental restorations during cooling from high temperature processing. The aim of this study was to evaluate the influence of constructive design variables (composition and interlayer thickness) on residual stresses in alumina- and zirconia-graded restorations. Restorations' real-like cooling conditions were simulated using finite elements method and temperature-dependent material properties were used. Three different designs were evaluated: a bilayered restoration (sharp transition between materials); a trilayered restoration with a homogenous interlayer between core and veneer; and a trilayered restoration with a graded interlayer. The interlayer thickness and composition were varied. Zirconia restorations presented overall higher thermal stress values than alumina ones. Thermal stresses were significantly reduced by the presence of a homogeneous interlayer. The composition of the interlayer showed great influence on the thermal stresses, with the best results for homogeneous interlayers being observed for porcelain contents in the composite ranging between 30%-50% (vol.%), for both alumina and zirconia restorations. The interlayer's thickness showed a minor contribution in the thermal stress reduction. The graded interlayer showed an optimized reduction in restorations' thermal stresses. The use of graded interlayer, favoring enhanced thermal stress distributions and lower magnitude is expected to reduce the risk of catastrophic failure.

Couples' discontinuation of fertility treatments: a longitudinal study on demographic, biomedical, and psychosocial risk factors.

PURPOSE: This study aims to explore the role of infertility-psychosocial variables on treatment discontinuation after controlling for demographic and biomedical variables in couples seeking reimbursed fertility treatment. METHODS: A prospective study was conducted in 139 couples seeking fertility treatment. Between February 2010 and March 2011, participants completed measures of anxiety (STAI-State), depression (BDI-II), infertility-stress (FPI), and infertility coping strategies (COMPI-CSS). Medical data related to diagnosis, treatment, and discontinuation were collected in December 2013. A multiple logistic regression was performed to identify the predictors of discontinuation. RESULTS: The discontinuation rate was 29.5%. Female education level, engagement in ART procedures, and female causation decreased the likelihood of treatment discontinuation, whereas female age and depression increased the likelihood of discontinuation. Female depression was the strongest predictor in this model. The model correctly identified 75.5% of cases. CONCLUSIONS: Female age and female depression are associated with a higher likelihood of treatment discontinuation in couples seeking treatment. Reproductive health professionals should therefore inform couples about the link between the fertility treatment discontinuation and both female age and female depression. Couples in which female partners present clinically relevant depression should be referred to a mental health professional to prevent premature abandonment of fertility treatments and thus increase success rates.

The bending stress distribution in bilayered and graded zirconia-based dental ceramics.

The purpose of this study was to evaluate the biaxial flexural stresses in classic bilayered and in graded zirconia-feldspathic porcelain composites. A finite element method and an analytical model were used to simulate the piston-on-ring test and to predict the biaxial stress distributions across the thickness of the bilayer and graded zirconia-feldspathic porcelain discs. An axisymmetric model and a flexure formula of Hsueh et al. were used in the FEM and analytical analysis, respectively. Four porcelain thicknesses were tested in the bilayered discs. In graded discs, continuous and stepwise transitions from the bottom zirconia layer to the top porcelain layer were studied. The resulting stresses across the thickness, measured along the central axis of the disc, for the bilayered and graded discs were compared. In bilayered discs, the maximum tensile stress decreased while the stress mismatch (at the interface) increased with the porcelain layer thickness. The optimized balance between both variables is achieved for a porcelain thickness ratio in the range of 0.30-0.35. In graded discs, the highest tensile stresses were registered for porcelain rich interlayers (p=0.25) whereas the zirconia rich ones (p=8) yield the lowest tensile stresses. In addition, the maximum stresses in a graded structure can be tailored by altering compositional gradients. A decrease in maximum stresses with increasing values of p (a scaling exponent in the power law function) was observed. Our findings showed a good agreement between the analytical and simulated models, particularly in the tensile region of the disc. Graded zirconia-feldspathic porcelain composites exhibited a more favourable stress distribution relative to conventional bilayered systems. This fact can significantly impact the clinical performance of zirconia-feldspathic porcelain prostheses, namely reducing the fracture incidence of zirconia and the chipping and delamination of porcelain.

Semen parameters and their influence on pregnancy after assisted reproduction: Report of the Hospital Centre of Porto / Parámetros seminales y su influencia en las técnicas de reproducción asistida: experiencia del Centro Hospitalario de Porto

Introduction: Several studies analyzed the possible relationships between semen parameters and assisted reproductive technologies (ART) treatments. However, none could establish a threshold to guide in the decision of which treatment technique will be better facing spermiogram values. Objectives: A database with spermiogram and clinical parameters was built in order to search for relevant interactions between semen parameters and different ART treatment techniques. Materials and methods: A general statistical analysis evaluated semen parameters, followed by correlations to study their influence on the pregnancy rate for each type of treatment technique. Results: A predominance of teratozoospermia and asthenozoospermia was observed, with strong positive correlations between age and total motility, as well as obvious correlations between concentration and motility. Of the studied population, 41.8% went for ART consultations and presented a mean time of infertility of 2.9 years, a mean male age of 33.4 years and a mean female age of 31.9 years. Of these, 17.1% achieved a spontaneous pregnancy. Of the treatment cycles, 13.1% were by intra-uterine insemination (10.2% of clinical pregnancy rate, CP, with six newborn, NB), 24.9% by in vitro-fertilization (21.7 CP, 18 NB) and 44.9% by intracytoplasmic sperm injection (25.3% CP, 40 NB). From the analysis between semen parameters and the pregnancy rates, per type of ART technique, a significant positive correlation between techniques was found, revealing thresholds associated with the probability of a successful clinical pregnancy. Conclusions: The present results suggest that spermiogram reference limits can be developed for each treatment technique that are associated with a higher probability of achieving a clinical pregnancy (AU)

Introducción: Varios estudios han examinado las posibles relaciones entre los parámetros seminales y los resultados derivados de los tratamientos de infertilidad. Sin embargo, no hemos logrado establecer umbrales que puedan guiar a la hora de la decisión de que técnica de reproducción asistida (ART) se debe elegir. Objetivos: Se construyó una base de datos con los parámetros seminales y los resultados clínicos de los tratamientos de infertilidad para que se puedan investigar las interacciones relevantes entre ellos. Materiales y métodos: Después de un análisis estadístico general de los parámetros seminales, se realizó un estudio de correlación entre aquellos y las tasas de embarazo por la técnica de tratamiento. Resultados: Hubo un predominio de teratospermia y astenozoospermia, con fuertes correlaciones entre la edad y la motilidad total, así como correlaciones evidentes entre la concentración y la motilidad. En la población de estudio, el 41,8% ha visitado las consultas de infertilidad, presentando un tiempo medio de 2,9 años de infertilidad, y una edad media de 33,4 (hombres) y 31,9 (mujeres) años. De éstas, el 17,1% logró un embarazo espontáneo. De los tratamientos de ART realizados, 13,1% se debieron a la inseminación intrauterina (tasa de embarazo clínico del 10,2%, GC, con 6 recién nacidos, RN), el 24,9% en la fertilización in vitro (21.7 GC, RN 18) y 44,9% por microinyección intracitoplasmática de espermatozoides (25,3% GC, RN 40). Del análisis entre los parámetros seminales y las tasas de embarazo, para cada tipo de técnica de tratamiento, se observó una correlación significativa entre las técnicas, revelando los umbrales asociados a la probabilidad de lograr con éxito un embarazo clínico. Conclusiones: Los datos sugieren que pueden ser creados los umbrales de referencia de los parámetros seminales para cada técnica de tratamiento, los cuales están más fuertemente asociados con la capacidad de lograr con éxito un embarazo clínico (AU)

[Successful pregnancies outcomes with the use of in vitro fertilization after Essure® unilateral hydrossalpinx occlusion]. / Gravidezes bem sucedidas com recurso a fertilização in vitro após oclusão de hidrossalpinge unilateral com Essure®

INTRODUCTION: Since two decades we witnessed the publication of several studies devoted to the study of the influence of the presence of hydrosalpinx on the results of embryo transfer techniques. The aim of this study is to present the results of treatment and pregnancy outcomes in women with a history of infertility associated with unilateral hydrosalpinx, visible on vaginal ultrasound, which were subjected to unilateral occlusion with Essure® and subsequent treatment with in vitro fertilization. MATERIAL AND METHODS: We performed a prospective analysis of a sample of 6 women, with a history of infertility and unilateral hydrosalpinx, between April 2010 to May 2013. In all cases we proceeded to unilateral hysteroscopic placement of the Essure® microinsert, prior to performing a cycle for in vitro fertilization. RESULTS: Of the 6 patients undergoing in vitro fertilization, 4 became pregnant (66.7%). Of these, two were uneventful pregnancies until delivery and 2 are still under surveillance, without complications. Of the patients who did not become pregnant after in vitro fertilization (n = 2, 33.3%), 1 conceived spontaneously during the subsequent monitoring. DISCUSSION: The advancement of hysteroscopy in the treatment of hydrosalpinx using the Essure® microinsert placement is a valid alternative to the laparoscopic approach. CONCLUSION: This study suggests the effectiveness of unilateral tubal occlusion caused by Essure® microinsert in improving outcomes of in vitro fertilization treatment in cases of infertility associated with unilateral hydrosalpinx, visible in the vaginal ultrasound.

Introdução: Desde há duas décadas que assistimos à publicação de vários estudos dedicados à avaliação da influência da hidrossalpinge nos resultados de técnicas de transferência de embriões. O objectivo deste trabalho é apresentar os resultados do tratamento e vigilância gestacional em mulheres com história de infertilidade - associada a hidrossalpinge unilateral, visível no exame ecográfico transvaginal - submetidas a oclusão unilateral com Essure® e tratamento subsequente com fertilização in vitro. Material e Métodos: Análise prospectiva de uma amostra constituída por seis mulheres, com antecedentes de infertilidade e hidrossalpinge unilateral, entre Abril de 2010 e Maio de 2013. Em todos os casos procedemos a exclusão de hidrossalpinge recorrendo à colocação unilateral de um dispositivo Essure® por via histeroscópica antes da realização de um ciclo para fertilização in vitro. Resultados: Das seis doentes submetidas a fertilização in vitro, quatro engravidaram (66,7%). Destas, registaram-se duas gravidezes de termo sem intercorrências até ao parto e duas gravidezes encontram-se em vigilância, sem intercorrências conhecidas até à data. Das doentes que não engravidaram após fertilização in vitro (n = 2, 33,3%), uma engravidou espontaneamente durante a vigilância subsequente. Discussão: O avanço da histeroscopia no tratamento de hidrossalpinge, recorrendo à implantação do dispositivo Essure®, representa uma alternativa válida à abordagem laparoscópica. Conclusão: Este estudo sugere que a oclusão tubar unilateral, induzida pelo dispositivo Essure®, melhora os resultados do tratamento com fertilização in vitro em casos de infertilidade associada a hidrossalpinge unilateral, visível no exame ecográfico transvaginal.