Scanning Electron Microscopy Evaluation Research Articles

Nintedanib alleviates polypropylene mesh-induced adhesion in rabbit ventral herniorrhaphy

Abstract BACKGROUND: Nintedanib (previously known as BBIF 1120) was approved by the United States Food and Drug Administration and European Medical Agency to treat idiopathic lung fibrosis in the year 2014 and 2015, respectively. It is now gaining interest for its anti-fibrotic activity in other organs and disease conditions. Although a surgical mesh is used as a mainstay therapy for herniorrhaphy, postoperative peritoneal adhesion with a polypropylene mesh is a significant drawback. This study aims to assess the efficacy of nintedanib in preventing postoperative adhesion incited with a polypropylene mesh in a rabbit model of ventral hernia. MATERIALS AND METHODS: Ventral hernia was induced surgically in ten adult healthy New Zealand White rabbits of either sex. Hernioplasty was performed with a polypropylene mesh, and the rabbits were randomly allocated into two groups to receive either oral 1 ml sterile water or 100 mg nintedanib in 1 ml of sterile water for 7 days. The adhesion of the implanted mesh with the intra-abdominal organs was assessed clinically, by histological and ultrastructural studies with scanning electron microscopy (SEM) at 30 days postoperatively. RESULTS: All rabbits were clinically healthy for 30 days post-surgery with no complication at the site of surgery. The incidence of peritoneal adhesion and tenacity was less in the nintedanib group versus the control group (P = 0.00105). Histopathological and SEM evaluations also indicated less fibrosis and adhesion in the nintedanib-treated group versus control. CONCLUSION: Our results show successful prevention of mesh-associated adhesion with nintedanib, but further studies on the mechanistic pathway, pharmacokinetics, dose standardization, and evaluation of systemic side effects are warranted.

Electrospun chitosan//ethylcellulose-vitamin E//ethylcellulose-curcumin tri-chamber eccentric Janus nanofibers for a joint antibacterial and antioxidant performance

Multifunctional materials with both antibacterial and antioxidant properties are highly desired in many scientific applications. The combination of polysaccharide and multi-chamber nanostructures offers a novel perspective for developing antibacterial and antioxidant nanomaterials. In this study, a new kind of tri-chamber eccentric Janus nanostructures (TEJNs) was fabricated through a single-step and straight forward tri-fluid side-by-side electrospinning. The all-in-one TEJNs contained an outer chitosan (CS) chamber, a middle and an inner ethylcellulose (EC)-based chamber loaded with curcumin (Cur) and vitamin E (VE), respectively. The side-by-side multiple-fluid electrospinning processes were implemented robustly and continuously based on a homemade spinneret. Transmission electron microscope and scanning electron microscope evaluations demonstrated the tri-chamber inner structures of TEJNs and the linear morphologies, respectively. The Fourier transform infrared and X-ray diffraction results verified that the components were compatible and coexisted in an amorphous state. In vitro dissolution tests indicated that the TEJNs could provide a sustained release of 90 % of the loaded Cur and VE for 34.30 h and 24.86 h, respectively. Antibacterial and antioxidant experiments demonstrated that the TEJNs were able to provide enhanced antibacterial and antioxidant effects compared to the traditional electrospun homogeneous nanofibers. In the future, the Janus nanofibers can be further developed for several human health applications, such as wound dressings, active food packaging membranes, dental implants and cosmetic films.

Scanning Electron Microscopic Evaluation of Surface Defects of Remover Retreatment File After Single and Multiple Uses.

This study aimed to evaluate surface defects of Remover rotary Nickel-Titanium (NiTi) files after single and multiple uses in conventional endodontic retreatment procedures using scanning electron microscopy (SEM). Eighty acrylic blocks, simulating root canals with a 1.5 mm internal diameter, a 5 mm radius of curvature, and a 55° curvature, were utilized. After chemomechanical preparation and obturation, 24 new Remover files (N30, 7%, L23) were randomly assigned to three groups: single use, triple use, and six uses. The files were operated at 600 rpm with a torque of 2.5 Ncm, cleaned, and sterilized after each use. SEM analysis at magnifications of 100x, 250x, and 500x revealed surface defects, including tip deformation, microcracks, fracture, unwinding, surface pitting, and blade disruption. Deformation was observed in 75% of the files after a single use and in 100% of the files after three and six uses. Microcracks were absent after single use but appeared in 25% and 87.5% of files after three and six uses, respectively, showing a statistically significant increase (p < 0.001). Surface pitting also significantly increased among groups (p = 0.004). No fractures were observed in any group. The most common defects were tip deformation (91.7%) and surface pitting (70.8%). The findings suggest that repeated use of NiTi files significantly increases surface defects, elevating the risk of fatigue fractures. Thus, the results recommend limiting the reuse of Remover files to a maximum of 3x. Further research is needed to correlate defect types with anatomical factors and to assess file effectiveness in retreatment scenarios.

Emotion Recognition Using EEG Signals through the Design of a Dry Electrode Based on the Combination of Type 2 Fuzzy Sets and Deep Convolutional Graph Networks.

Emotion is an intricate cognitive state that, when identified, can serve as a crucial component of the brain-computer interface. This study examines the identification of two categories of positive and negative emotions through the development and implementation of a dry electrode electroencephalogram (EEG). To achieve this objective, a dry EEG electrode is created using the silver-copper sintering technique, which is assessed through Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Analysis (EDXA) evaluations. Subsequently, a database is generated utilizing the designated electrode, which is based on the musical stimulus. The collected data are fed into an improved deep network for automatic feature selection/extraction and classification. The deep network architecture is structured by combining type 2 fuzzy sets (FT2) and deep convolutional graph networks. The fabricated electrode demonstrated superior performance, efficiency, and affordability compared to other electrodes (both wet and dry) in this study. Furthermore, the dry EEG electrode was examined in noisy environments and demonstrated robust resistance across a diverse range of Signal-To-Noise ratios (SNRs). Furthermore, the proposed model achieved a classification accuracy of 99% for distinguishing between positive and negative emotions, an improvement of approximately 2% over previous studies. The manufactured dry EEG electrode is very economical and cost-effective in terms of manufacturing costs when compared to recent studies. The proposed deep network, combined with the fabricated dry EEG electrode, can be used in real-time applications for long-term recordings that do not require gel.

A scanning electron microscope evaluation of surface roughness of different clear aligners – A comparative in-Vitro study

Clear aligner are thermoplastic polyurethane materials which produces small increments of tooth movements by each aligner tray. Clinical effectiveness of the treatment largely depend on the mechanical properties of the material. The use of scanning electron microscopy (SEM) in invitro environment allows to evaluate the surface morphology of the aligners The aim of the study is to compare the surface roughness of different types of clear aligners after thermoforming and after invitro aging. A sample of 15 aligners from Group A (DURAN), Group B (ERKODUR), Group C (MONOFLEX) were taken for this study. After screening the subjects were scanned by intraoral scanner and STL file were imported to Maestero 3D software. Then resin models were printed and aligners were fabricated in the models by thermoforming machine. The first set of aligners were scanned by Scanning Electron Microscope and another set of aligners were placed in chewing simulator for simulating intraoral environment. Then the second set of aligners were sent for SEM evaluation. Mean comparison of surface roughness and root mean square surface roughness was compared by paired t test and comparison among the groups was done by one way ANOVA test. The surface roughness of both aligners increased after thermoforming. This could be due to thermoforming process which could be due to temperature variation. After the ageing of the aligners in the invitro environment, there is homogenous and smooth layer of the aligner surfaces which could be due to adhesion of biofilm and polishing effect by chewing strokes.

Adsorption of Pb(II) ions using a biosorbent derived from pineapple peel

Abstract The potential of pineapple peel as a biosorbent for a heavy metal, Pb(II), was investigated. The experiment was carried out at various contact times, doses of adsorbent, and pH of the solution. Results obviously showed that pineapple peel biosorbent has potential for removing Pb(II) ions from aqueous solutions. The adsorption of Pb(II) ions depended on the pH of the solution. No significant difference was observed when the adsorption was performed at pH of 4.0 and 5.0. The scanning electron microscope (SEM) evaluation indicated that the surface of pineapple peel (PP) biosorbent is arranged like flakes and fractures, in addition some pores are also present. The biosorbent made from pineapple peel showed a cloud-like layer in the SEM image after adsorption, showing that the Pb(II) ions were successfully adsorbed. About &gt;90% of 100 ppm Pb(II) ions were adsorbed within 5 minutes, indicating that the biosorbent derived from pineapple peel has a fast adsorption capacity. In conclusion, our investigation clearly showed the potential of biosorbent-derived pineapple peel to remove heavy metals, including Pb(II) ions, from solutions.

Scanning Electron Microscopy (SEM) Evaluation of the Ultrastructural Effects on Conjunctival Epithelial Cells of a New Multiple-Action Artificial Tear Containing Cross-Linked Hyaluronic Acid, Cationic Liposomes and Trehalose.

The authors performed an ex vivo and in vivo evaluation of the ultrastructural effects on the conjunctival epithelial cells of a new multiple-action tear substitute containing cross-linked hyaluronic acid, lipids and trehalose (Trimix®), using scanning electron microscopy (SEM) with conjunctival impression cytology. The ex vivo study highlights the persistence and distribution of the product at 5 and 60 min on a monolayer of conjunctival epithelial cells and an increase in microvilli density at the 60 min evaluation. In vivo examination was conducted on three subjects with different grades of ocular surface inflammation, treated with one drop of the product twice daily for thirty days. At the baseline (T0) and twelve hours after the last administration of the tear drop (T30), impression cytology of the upper bulbar conjunctiva for SEM evaluation of conjunctival epithelial cells was carried out. Slit lamp examination (SLE), corneal and conjunctival Fluotest, tear film break-up time (TBUT), and ocular surface disease index (OSDI) questionnaires were also performed to correlate the ultrastructural results with the clinical findings. After 30 days of treatment, a significant improvement in all clinical and symptomatic parameters and in the condition of the ocular surface was detected, with microvillar regeneration and strengthening in all the patients, and a complete restoration in 2/3 of them. The persistence and distribution of the product on the epithelial cells was also noted 12 h after the last administration. The results, therefore, suggest a marked epitheliotropic effect along with a high residence time of the tear substitute.

Evaluation of flexural strength and microhardness in Vaccinium macrocarpon (cranberry)-added self-cure polymethyl methacrylate dental resin: An in vitro study.

Occurrence of denture stomatitis and prosthesis breakage are common problems faced by elderly people wearing removable dentures. To overcome this, several attempts are made to improve the denture material by addition of antimicrobials without compromising original properties. The aim of the study was to evaluate flexural strength and microhardness of self-cured polymethyl methacrylate (PMMA) denture base resin after addition of Vaccinium macrocarpon (commonly called as cranberry), extract as antimicrobial, at varying proportions. Experimental in vitro study. Frozen cranberry fruits were subjected to extraction process in the presence of aqueous solvents. Lyophilized extract was added in proportions of 0, 0.5, 1.0, 1.5, and 2.0 dry wt/wt % into polymer of self-cure PMMA denture base resin. Based on cranberry inclusion, the study comprised one control (0%) and four test groups (0.5%-2%) with total of 100 samples. A three-point bending test for flexural strength was done for fifty study samples (n = 10). Surface of fractured samples was analyzed using a scanning electron microscope (SEM). Microhardness was determined using Vickers hardness test. One-way statistical ANOVA test was done to find the difference between groups, followed by Tukey's post hoc test for multiple pairwise comparison. Flexural strength ranged from 66.80 to 69.28 MPa, and a statistically insignificant difference was observed between groups (P > 0.05). SEM evaluation showed uniformly dispersed strands of cranberry extract in PMMA matrix. With higher concentration, less voids were seen. Vickers microhardness value significantly decreased from 15.96 in the control group to 14.57 with 2% cranberry addition (P < 0.05). Incorporation of cranberry extract into self-cure PMMA denture base resin, up to 2 dry wt %, did not decline the flexural strength. However, there was a significant decrease in Vickers microhardness values when compared against the control group (0% cranberry inclusion).

Three Self-Adhesive Resin Cements and Their Influence on the Marginal Adaptation of Zirconia-Reinforced Lithium Silicate Single Crowns: An In Vitro Scanning Electron Microscope Evaluation.

Background: In everyday dentistry, monolithic single crowns can be cemented with self-adhesive resin cements. The aim of this in vitro study was to evaluate how the marginal adaptation of full monolithic zirconia-reinforced lithium silicate (ZLS) single crowns is influenced by three different self-adhesive resin cements. Methods: Forty-five typodont teeth fully prepared for full monolithic crowns were divided into three groups (fifteen each) for the use of three different self-adhesive resin cements. A fourth control group (Temp-bond) was created by taking five teeth from each group before cementation with self-adhesive resin cements. All forty-five abutments were scanned using a Primescan intra-oral scanner (IOS), followed by computer-aided design (CAD) and computer-aided manufacturing (CAM) of zirconia-reinforced lithium silicate (ZLS) full crowns using a four-axis machine. Initially, the crowns of the control group were fixed to the abutments using Temp-bond, and the marginal gap was evaluated using a scanning electron microscope (SEM). After removing the control group crowns from the abutments, fifteen crowns in each group were cemented using a different self-adhesive resin cement and observed under SEM for evaluation of the marginal gap. A Kolmogorov-Smirnov test was performed, indicating no normal distribution (p < 0.05), followed by Mann-Whitney tests (α = 0.05). Results: The total mean marginal gap of the temp-bond control group was significantly lower compared to all three groups of self-adhesive resin cement (p < 0.0005). The total mean marginal gap of the G-cem ONE group was significantly lower compared to the TheraCem group (p < 0.026) and RelyX U200 group (p < 0.008). The total mean marginal gap of the TheraCem group was significantly higher than the G-cem ONE group (p < 0.026) but showed no significant difference with the RelyX U200 group (p > 0.110). Conclusions: All four groups showed a clinically acceptable marginal gap (<120 microns). Although all three groups of self-adhesive resin cement showed a significant increase in the marginal gap compared to the temp-bond control group, they were within the limits of clinical acceptability. Regarding the marginal gap, in everyday dentistry, it is acceptable to use all three self-adhesive resin cements, although the G-cem ONE group exhibited the lowest marginal gap for ZLS single crowns.

Revitalising Dentin Surfaces: Unlocking Periodontal Regeneration Potential through Cutting-edge Citric Acid Techniques

Introduction: Teeth affected by periodontitis exhibit an increased mineral content and endotoxins. They do not harmonise with the neighbouring periodontal cells, whose growth is essential for periodontal regeneration. This scanning electron microscope (SEM) study evaluated and compared the in vitro effects of different citric acid application techniques on naturally preserved dentin slabs. Materials and Methods: Thirty-two dentinal slabs were prepared for experimentation, with one group undergoing various treatments and a control group left untreated. The citric acid solution, with a pH of 1.0, was meticulously prepared and used in four different application methods on the experimental group. The dentin slabs were prepared for SEM evaluation, which assessed parameters such as exposed dentinal tubules, the surface area occupied by tubule orifices, the demineralised zone’s width and the exposed tubules’ morphological characteristics. Results: The data present the mean number of exposed dentinal tubules for different application techniques and the width of the demineralised zone. While the f-test did not show significant differences in the width of the demineralised zone, the number of exposed dentinal tubules varied significantly. Immersion treatment resulted in the highest number of open tubules, followed by cotton pellet placement and brushing. Conclusions: The study suggests that in periodontal regenerative procedures, passive citric acid application may be more effective than vigorous methods like burnishing for exposing inter-tubular fibrils and dentinal openings.

Evaluation of canal patency and cleanliness following retreatment of bioceramic sealer-obturated root canals using three different irrigant activation protocols.

This study evaluated the effectiveness of three different irrigant activation techniques in cleaning and establishing patency during retreatment of root canals obturated with gutta-percha and bioceramic sealer. 60 extracted premolars with oval-shaped canals were instrumented and obturated with gutta-percha and EndosequenceBC sealer using the 'warm hydraulic condensation' technique. The teeth were retreated using Protaper Universal Retreatment and XP-Endo Shaper system and divided into four groups according to the irrigant activation protocol used: control, passive ultrasonic irrigation (PUI), Endovac irrigation (EVI) and XP-Endo Finisher R (XPFR). Apical patency was achieved in all the samples of the XPFR group (100%), which showed a significantly higher success rate compared with the control (73.3%) and EVI groups (73.3%) (p < 0.05). The scanning electron microscopic evaluation revealed significantly cleaner middle and apical third root canals in the PUI and XPFR groups compared with the control group (p < 0.05). These findings suggest that XPFR effectively cleans and establishes patency in root canals filled with bioceramic sealers.

Evaluating Bacterial Spore Preparation Methods for Scanning Electron Microscopy.

Scanning electron microscopy (SEM) can reveal the ultrastructure of bacterial spores, including morphology, surface features, texture, spore damage, germination, and appendages. Understanding these features can provide a basis for adherence, how physical and environmental stressors affect spore viability, integrity, and functionality, as well as the distribution and function of surface appendages. However, the spore sample preparation method can significantly impact the SEM images' appearance, resolution, and overall quality. In this study, we compare different spore preparation methods to identify optimal approaches for preparation time, spore appearance and resolved features, including the exosporium and spore pili, for SEM imaging. We use Bacillus paranthracis as model species and evaluate the efficacy of preparation protocols using different fixation and drying methods, as well as imaging under room- and cryogenic temperatures. We compare and assess method complexity to the visibility of the spore exosporium and spore appendages across different methods. Additionally, we use Haralick texture features to quantify the differences in spore surface appearance and determine the most suitable method for preserving spore structures and surface features during SEM evaluation. The findings from this study will help establish protocols for preparing bacterial spores for SEM and facilitating accurate and reliable analysis of spores' characteristics.

H-ras-targeted genetic therapy remarkably surpassed docetaxel treatment in inhibiting chemically induced hepatic tumors in rats

AimsHepatocellular carcinoma (HCC) is still a leading cause of cancer-related death worldwide. But its chemotherapeutic options are far from expectation. We here compared H-ras targeted genetic therapy to a commercial docetaxel formulation (DXT) in inhibiting HCC in rats. Main methodsAfter the physicochemical characterization of phosphorothioate-antisense oligomer (PS-ASO) against H-ras mutated gene, the PS-ASO-mediated in vitro hemolysis, in vivo hepatic uptake, its pharmacokinetic profile, tissue distribution in some highly perfused organs, its effect in normal rats, antineoplastic efficacy in carcinogen-induced HCC in rats were evaluated and compared against DXT treatment. Mutated H-ras expression by in situ hybridization, hep-par-I, CK-7, CD-15, p53 expression patterns by immunohistochemical methods, scanning electron microscopic evaluation of hepatic architecture, various hepatic marker enzyme levels and caspase-3/9 apoptotic enzyme activities were also carried out in the experimental rats. Key findingsPS-ASO showed low in vitro hemolysis (<3 %), and had a sustained PS-ASO blood residence time in vivo compared to DTX, with a time-dependent hepatic uptake. It showed no toxic manifestations in normal rats. PS-ASO distribution was although initially less in the lung than liver and kidney, but at 8 h it accumulated more in lung than kidney. Antineoplastic potential of PS-ASO (treated for 6 weeks) excelled in inhibiting chemically induced tumorigenesis compared to DTX in rats, by inhibiting H-ras gene expression, some immonohistochemical modulations, and inducing caspase-3/9–mediated apoptosis. It prevented HCC-mediated lung metastatic tumor in the experimental rats. SignificancePS-ASO genetic therapy showed potential to inhibit HCC far more effectively than DXT in rats.

Modified Bamboo Shoots Flour Derived from the Ampel Gading Bamboo (Bambusa vulgaris Schrad var. Striata): Physicochemical Properties and Potential Applications as a Thickening Agent

Modified flour is widely used in the food industry to enhance viscosity and texture. Previous research has investigated fermenting Bamboo Shoots Flour from Ampel Gading Bamboo which is rich in fiber. Physical process combination, like temperature changes, and chemical modifications using acids or bases, may alter the flour's gel-forming properties, thereby expanding its applications, including as a thickening agent. The objective of this study is to evaluate the physicochemical properties and potential applications of Modified Bamboo Shoots Flour (MBFS) as a thickening agent. The analysis demonstrated that MBSF comprises 28.41% carbohydrates, with 4.88% crude fiber and 18.68% starch, featuring 4.74% amylose and 13.94% amylopectin (wet basis). Additionally, it contains 28.10% protein and 11.17% fat (wet basis), maintaining the characteristic form of MBSF. Scanning Electron Microscope (SEM) evaluation revealed the presence of ovate-shaped, rough and irregular surface starch granules. Heating a 2% MBSF suspension to 100°C increases viscosity, solubility, and swelling power. Low acidity (pH 10) enhances swelling power without affecting viscosity significantly. Both low acidity and heat treatments enhance the thickening properties of the MBFS. This study offers fundamental insights into the physical and chemical characteristics of MBFS, thereby facilitating its potential application in final products.

Development of ZTA (80% Al2O3/20% ZrO2) pre-sintered blocks for milling in CAD/CAM systems

The present work aims to develop a production method of pre-sintered zirconia-toughened-alumina (ZTA) composite blocks for machining in a computer-aided design and computer-aided manufacturing (CAD-CAM) system. The ZTA composite comprised of 80% Al2O3 and 20% ZrO2 was synthesized, uniaxially and isostatically pressed to generate machinable CAD-CAM blocks. Fourteen green-body blocks were prepared and pre-sintered at 1000 °C. After cooling and holder gluing, a stereolithography (STL) file was designed and uploaded to manufacture disk-shaped specimens projected to comply with ISO 6872:2015. Seventy specimens were produced through machining of the blocks, samples were sintered at 1600 °C and two-sided polished. Half of the samples were subjected to accelerated autoclave hydrothermal aging (20h at 134 °C and 2.2 bar). Immediate and aged samples were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Optical and mechanical properties were assessed by reflectance tests and by biaxial flexural strength test, Vickers indentation and fracture toughness, respectively. Samples produced by machining presented high density and smooth surfaces at SEM evaluation with few microstructural defects. XRD evaluation depicted characteristic peaks of alpha alumina and tetragonal zirconia and autoclave aging had no effect on the crystalline spectra of the composite. Optical and mechanical evaluations demonstrated a high masking ability for the composite and a characteristic strength of 464 MPa and Weibull modulus of 17, with no significant alterations after aging. The milled composite exhibited a hardness of 17.61 GPa and fracture toughness of 5.63 MPa m1/2, which remained unaltered after aging. The synthesis of ZTA blocks for CAD-CAM was successful and allowed for the milling of disk-shaped specimens using the grinding method of the CAD-CAM system. ZTA composite properties were unaffected by hydrothermal autoclave aging and present a promising alternative for the manufacture of infrastructures of fixed dental prostheses.

Innovative Formulations for Building Construction Bricks: Integration of Marble Dust and Lime as Alternatives to Clay for Improved Construction Brick Fabrication

This research offers a comprehensive examination of the production of bricks with leftover powdered marble and lime as eco-friendly materials. Different replacement percentages of leftover marble powder and lime (3%, 6%, 9%, and 12%) were applied to the soil to create bricks. Through a series of laboratory experiments, including compression tests, heat transfer tests, and scanning electron microscope (SEM) evaluations, the mechanical, thermal, and microstructural characteristics of the bricks produced were carefully evaluated. Bricks with increasing percentages of waste marble powder and lime replacement were found to have significantly changed physical, mechanical, and microstructural qualities. The findings offer valuable insights into the potential use of leftover marble powder and lime as environmentally friendly additives in brick manufacturing, with a focus on opportunities to enhance both sustainability and usability.

SEM Evaluation of the Marginal Gap of Zirconia-Reinforced Lithium Silicate Full Crowns and the Effect of Post Crystallization: An In Vitro Study.

This study compared the influence of crystallization on marginal gap adaptation by using computer-aided design and manufacturing (CAD-CAM) for producing monolithic zirconia-reinforced lithium silicate (ZLS) ceramic crowns. A total of 25 plastic teeth were scanned using a Primescan intra-oral scanner (IOS), and ZLS crowns were ground. For each unit (abutment and crown), the marginal gap was evaluated pre crystallization and post crystallization at four regions of interest through the use of a scanning electron microscope (SEM). To compare the marginal gap between the two groups, a Kolmogorov-Smirnov test performed on the study variables indicated a normal distribution (p > 0.05) followed by paired samples T-tests (α = 0.0005). After crystallization, there were significantly higher circumferential marginal gaps (CMGs) for all four surfaces (distal (p = 0.0005), mesial (p = 0.0005), palatal (p = 0.0005), and buccal (p = 0.0005)). The total mean marginal gap (MMG) revealed a significantly higher result for the post-crystallization group (79.82 ± 7.86 μm) compared to the pre-crystallization group (24.25 ± 5.49 μm). The post-crystallization group showed a significantly higher marginal gap compared to the pre-crystallization group in all parameters, but both groups were in the clinically accepted threshold (<120 microns). In terms of the marginal gap, it is arguable whether to carry out post-crystallization for CELTRA® DUO crowns and achieve better mechanical properties but significantly increase the marginal gap.

Changes in physical properties of universal composites and CAD/CAM materials after bleaching and antioxidant applications: Scanning electron microscope and atomic force microscope evaluation.

To evaluate the effects of vital bleaching agents and the subsequent application of ascorbic acid (AA) to universal composites and resin-based CAD/CAM blocks on the physical properties of materials. In the study; G-enial A'chord (GCA), Filtek Ultimate (FU), Clearfil Majesty (CM) composites, and LAVA Ultimate (LU), Cerasmart (GCC) CAD/CAM blocks were used. The materials were divided into two subgroups based on the applied bleaching type (n = 30/group): office bleaching (OB) and home bleaching (HB). After bleaching, AA was applied to the samples. Surface roughness, microhardness, and color change values of all samples were measured at three stages: initial (I), post-bleaching (B), and post-bleaching+AA application (BA). Statistical analysis was performed using 3-way Mixed ANOVA with Bonferroni correction (p < .05). The BA of the HB group of CM; the B of the HB group of LU; the B roughness values of both the OB and HB groups of GCC were significantly lower than I. The microhardness values of all the materials examined decreased significantly after both bleaching (p < .05). With regard to the AA application, it significantly decreased Ra values in the HB group of CM. In addition, it significantly increased the microhardness values in the HB groups of CM and GCC. Also, the ΔE001 and ΔE002 values for the FU and GCC HB groups were significantly higher than in the OB groups (p < .05). Bleaching and AA application affected the physical properties of the materials. The physical properties of the materials either remained unchanged or improved with the application of AA after bleaching. RESEARCH HIGHLIGHTS: This article presents in vitro results of a new approach that has not been studied before. Ascorbic acid, used to increase the bond strength between the material-tooth after bleaching, was used to eliminate the adverse effects of bleaching on the physical properties of aesthetic restorative materials. Additionally, the effects of all procedures on the materials were examined using scanning electron microscopy (SEM) and atomic force microscopy (AFM). As a result of the study, it was concluded that the application of ascorbic acid after bleaching improved the physical properties of some of the materials.

Ultrathin Feldspathic Ceramic Veneers: A Pilot SEM Evaluation of Etched Intaglio Surfaces.

Ultrathin ceramic veneers are a viable therapeutic option to manage esthetic challenges in the anterior zone. Proper conditioning of the intaglio surface of porcelain veneers is essential to achieve an adequate bonding. In clinical practice, this is typically done with chemical etching using an acid-containing agent, such as hydrofluoric acid. While it is well established that the etching effect is dependent on etching time and the acid concentration, little is known about the impact of etching time and the veneer fabrication method. The purpose of this pilot study was to evaluate, using scanning electron microscopy (SEM), the effect that different etching-time protocols have on the intaglio surface characteristics of ultrathin ceramic veneers fabricated with either the platinum foil technique or the refractory die technique. Several replicas of an ultrathin feldspathic ceramic veneer for a maxillary central incisor were fabricated. Individual specimens were processed according to different intaglio surface-etching protocols: no etching, etching for 90 seconds, etching for 120 seconds, and etching for 150 seconds (9.6% hydrofluoric acid used for all etching groups). It was observed that the 120-second etching protocol resulted in a favorable microroughness surface pattern in the platinum foil group. This pattern was comparable to that obtained by etching for 90 seconds with hydrofluoric acid the intaglio surface of veneers fabricated with the refractory die technique. Increasing the etching time to 150 seconds did not result in a more favorable roughness pattern.

Infrastructure in the Age of Pandemics: Utilizing Polypropylene-Based Mask Waste for Durable and Sustainable Road Pavements.

When navigating the environmental exigencies precipitated by global pandemics, the escalation of mask waste presents a multifaceted dilemma. In this avant-garde research, we unveil a novel approach: harnessing the sterilized shredded mask residues (SMRs), predominantly composed of 100 wt. % polypropylene, as pioneering modifiers for asphalt. Distinct proportions of SMR (e.g., 3, 6, and 9 wt. %) were judiciously integrated with fresh-virgin base AP-5 asphalt and subjected to an extensive suite of state-of-the-art examinations, encompassing thin-layer chromatography-flame ionization detection (TLC-FID), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and specific rheological metrics. The TLC-FID diagnostic trajectories highlighted the nuanced rejuvenating influence of SMR on the binder, a facet reinforced by a pronounced elevation in the thermodynamic stability index (IC). The FT-IR spectra elucidated SMR's preeminent role as a filler, negating notions of chemical reactivity. The TGA analyses unveiled an elevated thermal onset of degradation, signposting enhanced thermal resilience, whereas the DSC readings illuminated a superior thermal comportment at lower extremities. The SEM evaluations rendered a clearer panorama: there was heightened textural perturbation at escalated SMR incorporations, yet the 3 wt. % concoction showcased an optimal, coherent microtexture symbiosis with asphalt. The rheological scrutinies revealed a systematic trajectory: a diminishing penetration and ductility countered by ascending softening points and viscosity metrics. The coup de maître stemmed from the DSR analyses, unequivocally validating SMR's unparalleled prowess in curtailing rutting distress. This seminal inquiry not only posits a blueprint for refined pavement longevity but also champions a sustainable countermeasure to pandemic-propelled waste, epitomizing the confluence of environmental prudence an d infrastructural fortitude.