Acid and Microhardness of Mineral Trioxide Aggregate and Mineral Trioxide Aggregate–like Materials

Introduction

The aim of this study was to compare the surface microhardness of BioAggregate, ProRoot MTA, and CEM Cement when exposed to an acidic environment or phosphate-buffered saline (PBS) as a synthetic tissue fluid.

Methods

Ninety cylindrical molds made of polymethyl methacrylate with an internal diameter of 6 mm and height of 4 mm (according to ASTM E384 standard for microhardness tests) were fabricated and filled with BioAggregate (n = 30), tooth-colored ProRoot MTA (n = 30), or CEM Cement (n = 30). Each group was then divided into 3 subgroups of 10 specimens consisting of those exposed to distilled water, exposed to PBS (pH = 7.4), or exposed to butyric acid (pH = 5.4). After 1 week the Vickers surface microhardness test was performed. Statistical analysis included 2-way analysis of variance, followed by post hoc Dunnett T3 in cases with lack of homoscedasticity and Tukey honestly significant difference in cases with homoscedasticity.

Results

The indentations obtained from the CEM Cement specimens exposed to an acidic pH were not readable because of incomplete setting. There was a significant difference between the microhardness of the materials regardless of the environmental conditions (P < .001). In all the environmental conditions, MTA had significantly higher and CEM Cement had significantly lower microhardness values (P < .001). All experimental cements had significantly higher microhardness values when exposed to PBS (P < .001) and had significantly lower microhardness values when exposed to butyric acid (P < .001).

Conclusions

The surface microhardness of BioAggregate, ProRoot MTA, and CEM Cement was reduced significantly by exposure to butyric acid and increased significantly by exposure to PBS. In all environmental conditions, MTA had significantly higher microhardness values.     

On the benefit of galls of Quercus brantii Lindl. in murine colitis: the role of free gallic acid

Introduction

In this study we investigated the effect of gall of Quercus brantii Lindl., a traditional Iranian medicine, in a murine model of experimental colitis induced in male rats by rectal administration of 2,4,6-trinitrobenzene sulfonic acid (TNBS).

Material and methods

Quantification of the main active components was done for estimation of total phenolic content and free gallic acid. Gall of Quercus brantii Lindl. in two forms (gall powder and gall hydro alcoholic extract) was gavaged for 10 days (500 mg/kg). Ten days after induction of colitis, colonic status was examined by macroscopic, microscopic and biochemical analyses. Colonic tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were analyzed as biomarkers of inflammatory condition. To determine the role of oxidative stress (OS) in colitis, the levels of cellular lipid peroxidation (LPO), total antioxidant power (TAP) and myeloperoxidase (MPO) were measured in colon tissues.

Results

TNBS-induced colitis exhibited a significant increase in colon MPO activity and concentrations of cellular LPO, TNF-α and IL-1β, while TAP was significantly reduced. Microscopic evaluations of the colonic damage in the colitis group revealed multifocal degenerative changes in the epithelial lining and areas of necrosis, extensive mucosal and sub-mucosal damage with congested blood vessels, edema and hemorrhages along with extensive infiltration of inflammatory cells. Parameters including macroscopic and microscopic scores, TNF-α, IL-1β, LPO, TAP and MPO improved by both gall extract and gall powder of Quercus brantii Lindl. and reached close to normal levels. The level of total phenols (GAE/100 g of sample) and free gallic acid were estimated to be 88.43 ±7.23 (mean ± SD) and 3.74% of dry weight, respectively.

Conclusions

The present study indicates that the gall of Quercus brantii Lindl. is able to exert antioxidative and anti-inflammatory effects on the biochemical and pathological parameters of colitis.     

Fabrication and performance evaluation of new nanocomposite membranes based on sulfonated poly(phthalazinone ether ketone) for PEM fuel cells

The purpose of this work is to enhance the proton conductivity and fuel cell performance of sulfonated poly(phthalazinone ether ketone) (SPPEK) as a proton exchange membrane through the application of SrTiO₃ perovskite nanoparticles. Nanocomposite membranes based on SPPEK and SrTiO₃ perovskite nanoparticles were prepared via a casting method. The highest proton conductivity of nanocomposite membranes obtained was 120 mS cm⁻¹ at 90 °C and 95% RH. These enhancements could be related to the hygroscopic structure of SrTiO₃ perovskite nanoparticles and the formation of hydrogen bonds between nanoparticles and water molecules. The satisfactory power density, 0.41 W cm⁻² at 0.5 V and 85 °C, of the nanocomposite membrane (5 wt% content of nanoparticles) confirms their potential for application in the PEM fuel cells.

The purpose of this work is to enhance the proton conductivity and fuel cell performance of sulfonated poly(phthalazinone ether ketone) (SPPEK) as a proton exchange membrane through the application of SrTiO₃ perovskite nanoparticles.     

Multivesicular hepatic human hydatid cyst from Iran: First genotyping‐based confirmation

Cystic echinococcosis is one of the most important zoonotic parasitic diseases caused by the tapeworm Echinococcus granulosus. To date, the genotype of multivesicular CE has not been identified. In this regard, the genotyping of multivesicular types of CE could help clinicians understand and manage the disease effectively.     

Mechanical Property Improvement in Dissimilar Friction Stir Welded Al5083/Al6061 Joints: Effects of Post-Weld Heat Treatment and Abnormal Grain Growth

The 5083 and 6061(T6) aluminum (Al) alloys are widely used in transportation industries and the development of structural designs because of their high toughness and high corrosion resistance. Friction stir welding (FSW) was performed to produce the dissimilar welded joint of Al5083-Al 6061(T6) under different welding parameters. However, softening behavior occurred in the friction stir welded (FSWed) samples because of grain coarsening or the dissolution of precipitation-hardening phases in the welding zone. Consequently, this research intended to investigate the effect of the post-weld heat treatment (PWHT) method on the mechanical property improvement of the dissimilar FSWed Al5083-Al6061(T6) and governing abnormal grain growth (AGG) through different welding parameters. The results showed PWHT enhanced the mechanical properties of dissimilar joints of Al5083-Al6061(T6). AGG was obtained in the microstructure of PWHTed joints, but appropriate PWHT could recover the dissolved precipitation-hardening particle in the heat-affected zone of the as-welded joint. Further, the tensile strength of the dissimilar joint increased from 181 MPa in the as-welded joint to 270 MPa in the PWHTed joint, showing 93% welding efficacy.     

Reconstruction of lingual sulcus in a severely atrophic mandible using a modified approach as a pre‐prosthetic surgery: Case series

Shallow lingual vestibule and lack of keratinized attached mucosa are considered risk factors for the long‐term success of dental implants. This article describes a modified surgical approach accompanied by a free gingival graft to correct the shallow lingual/buccal vestibule and to increase the keratinized tissue around dental implants.     

Tetrazol-Cu(i) immobilized on nickel ferrite catalyzed green synthesis of indenopyridopyrimidine derivatives in aqueous media

After the initial study of different protocols in the synthesis of indeno[2′,1′:5,6]pyrido[2,3-d]pyrimidines, herein, a new method is presented using cheaper and more accessible starting materials to produce high-efficiency products. In this protocol, the novel nanocatalyst is very effective in the progression of the reaction and increasing the efficiency. This green approach in aqueous media has several advantages as compared with other methods, such as easier work-up, very mild reaction conditions, reusability of the catalyst, and eco-friendliness. The products of this four-component condensation were evaluated using IR, ¹H NMR, ¹³C NMR spectra, and C. H. N. analyses, and the catalyst structure was confirmed by FT-IR, XRD, SEM, EDX, TGA and VSM techniques.

In this protocol, a novel nanocatalyst was very effective in progression of the reaction and increasing efficiency. This green approach in aqueous media has several advantages compared with the reported methods.