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CONTEXT: The smear layer may harbor many bacteria; hence, alternative methods are used to disrupt and remove biofilm. AIM: The aim of the study was to compare the effectiveness of EndoActivator, PATS Vario System, and XP-endo Finisher files on smear layer removal using a scanning electron microscope. SUBJECTS AND METHODS: Sixty single-rooted extracted premolars with Vertucci Type 1 configuration were decoronated and divided into four groups. The groups were instrumented with the rotary ProTaper file system. All specimens were flushed with 1 ml of 3% sodium hypochlorite. Group 1 was irrigated with a conventional needle and syringe. In Group 2, the irrigant was activated with an EndoActivator. In Group 3, the irrigant was activated with PATS Vario system, and in Group 4, XP-endo Finisher files were used after biomechanical preparation to remove debris and smear layer. All specimens were finally rinsed with 3 ml of 3% sodium hypochlorite. The teeth underwent longitudinal splitting and grooving in the coronal, middle, and apical thirds, and then, the samples were taken for scanning electron microscopy to evaluate the amount of smear layer removal in each third. RESULTS: The middle and coronal thirds Showed that almost similar efficacy to remove smear layer in both Group II and Group III. At the apical third, Group III showed comparatively better results than Group I, II, and IV, respectively. CONCLUSION: Equal amount of smear layer was seen with EndoActivator and PATS Vario system when used as sonic irrigation devices.
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Microscopía Electrónica de Rastreo , Preparación del Conducto Radicular , Capa de Barro Dentinario , Humanos , Preparación del Conducto Radicular/instrumentación , Preparación del Conducto Radicular/métodos , Diente Premolar , Hipoclorito de Sodio/uso terapéutico , Irrigantes del Conducto Radicular/uso terapéuticoRESUMEN
INTRODUCTION: Caries in primary teeth rapidly advances owing to its thin structure, thereby requiring restoration. However, restorations often fail due to various causes such as secondary caries and reduced microtensile bond strength (µTBS), which calls for the use of antimicrobial agents such as silver diamine fluoride (SDF). AIM: This study aims to measure and analyse the effect of SDF application on the µTBS of three regularly used restorative materials to dentin of primary teeth as well as compare the types of bond failure interfaces under SEM. MATERIALS AND METHODS: The study comprised 60 samples equally divided into six groups among three restorative materials, namely, glass ionomer cement (GIC, Groups I and II), resin-modified glass ionomer cement (RMGIC, Groups III and IV), and composite resin (Groups V and VI) with subdivisions of A and B, where A represented samples with SDF application and B represented samples without SDF application. RESULTS AND OBSERVATIONS: It was observed that µTBS of RMGIC to sound and carious dentin irrespective of SDF application was found to be statistically significant (P < 0.05), and when GIC, RMGIC, and composite resins were compared to both sound and carious dentin irrespective of SDF application, it was statistically significant (P < 0.05). SEM analysis revealed predominantly cohesive failures among all the groups. CONCLUSION: Based on the results, it was concluded that SDF has no adverse effect on the µTBS of GIC, RMGIC, and composite resin to both carious and sound dentin of primary teeth.
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Resinas Compuestas , Recubrimiento Dental Adhesivo , Fluoruros Tópicos , Cementos de Ionómero Vítreo , Compuestos de Amonio Cuaternario , Compuestos de Plata , Resistencia a la Tracción , Diente Primario , Humanos , Fluoruros Tópicos/farmacología , Resinas Compuestas/química , Cementos de Ionómero Vítreo/farmacología , Compuestos de Amonio Cuaternario/farmacología , Compuestos de Amonio Cuaternario/química , Recubrimiento Dental Adhesivo/métodos , Microscopía Electrónica de Rastreo , Dentina/efectos de los fármacos , Ensayo de Materiales , Restauración Dental Permanente/métodos , Caries Dental , Materiales Dentales/químicaRESUMEN
Nudibranchs, with their mesmerizing diversity and ecological significance, play crucial roles in marine ecosystems. Central to their feeding prowess is the radula, a chitinous structure with diverse morphologies adapted to prey preferences and feeding strategies. This study focuses on elucidating wear coping mechanisms in radular teeth of carnivorous molluscs, employing Dendronotus lacteus (Dendronotidae) and Flabellina affinis (Flabellinidae) as model species. Both species forage on hydrozoans. Through scanning electron microscopy, confocal laser scanning microscopy, nanoindentation, and energy-dispersive X-ray spectroscopy, the biomechanical and compositional properties of their teeth were analyzed. Notably, tooth coatings, composed of calcium (Ca) or silicon (Si) and high hardness and stiffness compared to the internal tooth structure, with varying mineral contents across tooth regions and ontogenetic zones, were found. The presence of the hard and stiff tooth coatings highlight their role in enhancing wear resistance. The heterogeneities in the autofluorescence patterns related to the distribution of Ca and Si of the coatings. Overall, this study provides into the biomechanical adaptations of nudibranch radular teeth, shedding light on the intricate interplay between tooth structure, elemental composition, and ecological function in marine molluscs.
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Gastrópodos , Diente , Animales , Gastrópodos/anatomía & histología , Gastrópodos/fisiología , Diente/anatomía & histología , Microscopía Electrónica de Rastreo , Espectrometría por Rayos X , Fenómenos BiomecánicosRESUMEN
The objective of this study was to study the impact of pressing time on the microstructure of goat cheese and its relationship with sensory attributes. The microstructure of the artisanal cheeses was performed by scanning electron microscopy and image analysis. The validation of the microstructural complexity was carried out experimentally with sensory attributes. The pressing time influenced the microstructural parameters Feretmax, Geodiam, and τ and the cheese type influenced the parameters Feretmax, Geodiam, and Geoelong. The correlation values between microstructural complexity and sensory attributes were 0.85 and 0.84 for fresh cheeses and matured cheeses, respectively. The pressure times of 12 and 18 h resulted in cheese microstructures with the highest complexity in terms of Feretmax, Geodiam, Geoelong, and τ parameters. The obtained results are supported by the correlation values between microstructural complexity and sensory attributes.
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Queso , Manipulación de Alimentos , Cabras , Microscopía Electrónica de Rastreo , Gusto , Queso/análisis , Animales , Humanos , Factores de Tiempo , PresiónRESUMEN
OBJECTIVE: Purpose of this research was to examine the onset, progression and wear rates of dental erosion in an established mouse model. MATERIAL AND METHODS: Dental erosion in mice was experimentally induced, and the acidic effects of cola drink on their teeth after 2, 4 and 6-weeks were closely analysed by scanning electron microscopy. The tooth height and enamel or dentin loss were established. Results: The dental erosion on the molars showed clear progression from 2 to 6 weeks. By the 2-week mark, a significant portion of enamel was already eroded, revealing the dentin on the lingual cusps. When adjusted for attritional wear, molars exposed to cola for 2 weeks showed a 35% drop in lingual tooth height compared to controls (533 µm vs. 818 µm). At 4 and 6 weeks, the cola-exposed group continued to display decreased lingual tooth heights by 40% (476 µm vs. 799 µm) and 43% (440 µm vs. 767 µm), respectively. CONCLUSION: This study revealed significant acidic effects of cola drink on mouse molars as early as 2 weeks. These findings highlight the challenge of monitoring dental erosion clinically and underscore the importance of early preventive and intervention measures.
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Modelos Animales de Enfermedad , Progresión de la Enfermedad , Erosión de los Dientes , Animales , Erosión de los Dientes/etiología , Erosión de los Dientes/patología , Ratones , Microscopía Electrónica de Rastreo , Bebidas Gaseosas/efectos adversos , Diente Molar , Masculino , Esmalte Dental/efectos de los fármacos , Esmalte Dental/patologíaRESUMEN
Laser lithotripsy mechanisms can cause the chemical decomposition of stone components and the emergence of different end products. However, the potentially toxic end products formed during thulium fiber laser (TFL) lithotripsy of cystine stones have not been sufficiently investigated. The aim of our in vitro study is to analyze the chemical content of the gas products formed during the fragmentation of cystine stone with TFL. Human renal calculi consisting of 100% pure cystine, calcium oxalate monohydrate, or uric acid were fragmented separately with TFL in experimental setups and observed for gas release. After the lithotripsy, only the cystine stones showed gas formation. Gas chromatography-mass spectrometry was used to analyze the gas qualitatively, and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) and X-ray diffraction was used to examine the dried cystine stone fragments. Fragmentation of the cystine stones released free cystine, sulfur, hydrogen sulfide, and carbon disulfide gas. The SEM-EDX and X-ray diffraction analyses revealed that the free cystine in the dried fragments contained 43.1% oxygen, 28.7% sulfur, 16.1% nitrogen, and 12.1% carbon atoms according to atomic weight. The detection of potentially toxic gases after lithotripsy of cystine stones with TFL indicates a risk of in vivo production. Awareness needs to be increased among healthcare professionals to prevent potential inhalation and systemic toxicity for patients and operating room personnel during TFL lithotripsy of cystine stones.
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Oxalato de Calcio , Cistina , Litotripsia por Láser , Microscopía Electrónica de Rastreo , Tulio , Ácido Úrico , Cistina/análisis , Cistina/química , Humanos , Oxalato de Calcio/análisis , Oxalato de Calcio/química , Litotripsia por Láser/métodos , Ácido Úrico/análisis , Tulio/química , Cálculos Renales/química , Cálculos Renales/terapia , Gases/análisis , Cromatografía de Gases y Espectrometría de Masas , Difracción de Rayos XRESUMEN
BACKGROUND: Dental implants are increasingly favored as a therapeutic replacement option for edentulism. Titanium (Ti), due to its excellent biocompatibility and unique osseointegration properties, is commonly used in dental implants. Various surface modifications have been explored to improve osseointegration outcomes. Graphene oxide (GO) is a promising material with various applications. Chitosan, found in the exoskeleton of crustaceans and in marine algae, has several biomedical applications. Silver (Ag) is another promising antibacterial agent that increases permeability and damages the bacterial cell membrane upon binding. OBJECTIVES: The present study applied a novel implant surface coating of Ag-decorated GO and chitosan on Ti implants to promote bone formation. We further analyzed the physiochemical and antibacterial properties of this surface coating. MATERIAL AND METHODS: A solution was prepared by mixing 3 mL of 1% chitosan solution with 10 mg of Ag-GO nanoparticles (NPs). Titanium metal was heated to 70-80°C on a hotplate and the solution was applied onto Ti to obtain an adhesive surface coating. The coated implant was further analyzed for surface properties, using scanning electron microscopy (SEM), the energy dispersive X-ray (EDX) analysis, the attenuated total reflectance-Fourier transform infrared (ATR-FTIR) technique, and the biocompatibility and corrosion analyses. RESULTS: The SEM analysis revealed a homogenously spread, rough, fibrillar and porous layer of coating on the metal surface. The EDX and ATR-FTIR analyses confirmed the successful coating of the implant surface with Ag-decorated GO and chitosan layers. The cell culture assay demonstrated excellent biocompatibility of the surface coating. The corrosion analysis showed improved corrosion resistance of the developed implant surface coating. CONCLUSIONS: The various analyses of the coating showed ideal properties for improved cell attachment, differentiation and proliferation while maintaining an antimicrobial environment on the implant surface.
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Quitosano , Materiales Biocompatibles Revestidos , Implantes Dentales , Grafito , Ensayo de Materiales , Plata , Propiedades de Superficie , Titanio , Quitosano/farmacología , Quitosano/química , Plata/farmacología , Corrosión , Antibacterianos/farmacología , Microscopía Electrónica de Rastreo , HumanosRESUMEN
Hyperspectral microscope imaging (HMI) technique was employed to assess the changes in physicochemical parameters and microstructure of 'Golden Delicious' apples flesh during storage. Four regions of interest (ROIs), including whole-cell ROI, intercellular space ROI, cytoplasm ROI, and cell wall ROI were investigated to assess their relationships with physicochemical parameters. Different ROIs presented similar vibrational profiles, but with slight differences in spectral intensity, especially in the range of 800-1000 nm. Spectral angle mapper (SAM) was applied to the HMI of apple tissues at different storage stages to clearly show the structural changes of parenchyma cells, while principal component analysis (PCA) could highlight the distribution of sugars, water and pigments in apple flesh at the cellular scale. Simultaneously with the degradation of acid-soluble pectin (ASP), middle lamella dissolution and increased intercellular space were observed using SEM and TEM. Single feature variables were used to construct linear models based on pearson correlation analysis, with R2 of 0.96 for moisture at 982 nm, 0.85 for water-soluble pectin (WSP) at 420 nm, 0.82 for L* at 946 nm, 0.77 for soluble solids content (SSC) at 484 nm, and 0.66 for firmness at 490 nm. This work demonstrated the great potential of HMI technology as a fast, accurate and efficient solution for assessing the quality of 'Golden Delicious' apples.
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Frutas , Imágenes Hiperespectrales , Malus , Pectinas , Malus/química , Frutas/química , Imágenes Hiperespectrales/métodos , Pectinas/química , Pectinas/análisis , Análisis de Componente Principal , Microscopía/métodos , Almacenamiento de Alimentos/métodos , Microscopía Electrónica de Rastreo , Pared Celular/químicaRESUMEN
Clematis, one of the largest genera of the family Ranunculaceae, has a wide array of morphological variation and is considered the most difficult group of taxa in terms of infrageneric discrimination. This study assessed the leaf micromorphological features of 19 Clematis taxa (16 species and three varieties) found in Korea. The leaf surface features were studied under scanning electron microscopy, and the stomatal counting and measurement were carried out under light microscopy. Clematis are hypostomatic, meaning the stomata are only found on the abaxial surface of the leaf. Observed taxa showed near uniformity in the epidermal cell type, structure, and morphology on both surfaces of the leaf. Differences were observed in the presence and absence and/or abundance of trichomes on both the adaxial and abaxial surfaces, the epidermal cell boundary, and the periclinal and anticlinal wall of the cells. Differences were also observed in the number of the epidermal cells connected with the stomata on the abaxial surface, with small differences noted in epidermal cell shapes. The ANOVA showed a significant variation in the stomata density in the studied taxa (P < 0.0001). The cluster analysis based on 13 leaf micromorphological features generated four major clusters. These results indicated similarities in certain key leaf micromorphological features among taxa from the Tubulosae, Clematis, and Virona sections. In the genus Clematis, as with other morphological characteristics, using leaf micromorphological characters alone, which possess limited taxonomic value, proves inadequate for resolving infrageneric relationships. However, incorporating certain features with other morphological characteristics offers a possible alternative means of determining the infrageneric relationships within the genus.
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Clematis , Microscopía Electrónica de Rastreo , Hojas de la Planta , Clematis/anatomía & histología , Hojas de la Planta/anatomía & histología , Hojas de la Planta/ultraestructura , República de Corea , Estomas de Plantas/ultraestructura , Estomas de Plantas/anatomía & histología , Epidermis de la Planta/ultraestructura , Epidermis de la Planta/anatomía & histología , Epidermis de la Planta/citología , Análisis por ConglomeradosRESUMEN
BACKGROUND: This study aimed to compare the marginal adaptation of a single customized gutta percha cone with calcium silicate-based sealer versus mineral trioxide aggregate (MTA) and Biodentine apical plugs in simulated immature permanent teeth. METHODS: Thirty-nine extracted human maxillary anterior teeth were selected, prepared to simulate immature permanent teeth with an apical diameter 1.1 mm, placed in moist foam and divided into three groups. Group 1: Obturation with a single customized gutta percha cone and calcium silicate sealer. Group 2: MTA apical plug. Group 3: Biodentine apical plug. After incubation, teeth were horizontally sectioned at 1 mm and 3 mm from the apex and marginal adaptation was evaluated using scanning electron microscope (SEM). RESULTS: Biodentine showed the least mean gap size at both 1 and 3 mm from the apex with no statistically significant differences compared to MTA (p > 0.05). The single customized cone with calcium silicate based sealer showed the greatest mean gap size at both 1 and 3 mm from the apex with a statistically significant difference compared to the other groups (p < 0.001). CONCLUSION: Biodentine and MTA apical plugs provide a significantly better marginal adaptation to the dentinal walls than a single customized gutta percha cone with calcium silicate based sealer in simulated immature permanent teeth.
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Compuestos de Aluminio , Compuestos de Calcio , Adaptación Marginal Dental , Combinación de Medicamentos , Gutapercha , Óxidos , Materiales de Obturación del Conducto Radicular , Silicatos , Humanos , Gutapercha/uso terapéutico , Técnicas In Vitro , Obturación del Conducto Radicular/métodos , Microscopía Electrónica de Rastreo , Ápice del Diente/efectos de los fármacos , Ensayo de MaterialesRESUMEN
Introduction: Our work aims at establishing a proof-of-concept for a method that allows the early prediction of the bactericidal and bacteriostatic effects of antibiotics on bacteria using scanning electron microscopy (SEM) as compared to traditional culture-based methods. Methods: We tested these effects using Imipenem (bactericidal) and Doxycycline (bacteriostatic) with several strains of sensitive and resistant Escherichia coli. We developed a SEM-based predictive score based on three main criteria: Bacterial Density, Morphology/Ultrastructure, and Viability. We determined the results for each of these criteria using SEM micrographs taken with the TM4000Plus II-Tabletop-SEM (Hitachi, Japan) following an optimized, rapid, and automated acquisition and analysis protocol. We compared our method with the traditional culture colony counting gold standard method and classic definitions of the two effects. Results: Our method revealed total agreement with the CFU method and classic definition by visualizing the effect of the antibiotic at 60 minutes and 120 minutes using SEM. Discussion: This early prediction allows a rapid and early identification of the bactericidal and bacteriostatic effects as compared to culture that would take a minimum of 18 hours. This has several future applications in the development of SEM-automated assays coupled to machine learning models that identify the antibiotic effect and facilitate determination of bacterial susceptibility.
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Antibacterianos , Doxiciclina , Escherichia coli , Imipenem , Pruebas de Sensibilidad Microbiana , Viabilidad Microbiana , Microscopía Electrónica de Rastreo , Antibacterianos/farmacología , Imipenem/farmacología , Doxiciclina/farmacología , Escherichia coli/efectos de los fármacos , Escherichia coli/ultraestructura , Viabilidad Microbiana/efectos de los fármacos , Recuento de Colonia MicrobianaRESUMEN
BACKGROUND: Different materials have been used as wound dressings after vital pulp therapies. Some of them have limitations such as delayed setting, difficult administration, slight degree of cytotoxicity, crown discoloration and high cost. Therefore, to overcome these disadvantages, composite scaffolds have been used in regenerative dentistry. This study aims to construct and characterize the physicochemical behavior of a novel injectable alginate hydrogel loaded with different bioactive glass nanoparticles in various concentrations as a regenerative pulpotomy filling material. METHODS: Alginate hydrogels were prepared by dissolving alginate powder in alcoholic distilled water containing mesoporous bioactive glass nanoparticles (MBG NPs) or boron-doped MBG NPs (BMBG NPs) at 10 and 20 wt% concentrations. The mixture was stirred and incubated overnight in a water bath at 50 0 C to ensure complete solubility. A sterile dual-syringe system was used to mix the alginate solution with 20 wt% calcium chloride solution, forming the hydrogel upon extrusion. Then, constructed hydrogel specimens from all groups were characterized by FTIR, SEM, water uptake percentage (WA%), bioactivity and ion release, and cytotoxicity. Statistical analysis was done using One-Way ANOVA test for comparisons between groups, followed by multiple pairwise comparisons using Bonferroni adjusted significance level (p < 0.05). RESULTS: Alginate/BMBG loaded groups exhibited remarkable increase in porosity and pore size diameter [IIB1 (168), IIB2 (183) (µm)]. Similarly, WA% increased (~ 800%) which was statistically significant (p < 0.05). Alginate/BMBG loaded groups exhibited the strongest bioactive capability displaying prominent clusters of hydroxyapatite precipitates on hydrogel surfaces. Ca/P ratio of precipitates in IIA2 and IIB1 (1.6) were like Ca/P ratio for stoichiometric pure hydroxyapatite (1.67). MTT assay data revealed that the cell viability % of human gingival fibroblast cells have declined with increasing the concentration of both powders and hydrogel extracts in all groups after 24 and 48 h but still higher than the accepted cell viability % of (Ë70%). CONCLUSIONS: The outstanding laboratory performance of the injectable alginate/BMBGNPs (20 wt%) composite hydrogel suggested it as promising candidate for pulpotomy filling material potentially enhancing dentin regeneration in clinical applications.
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Alginatos , Materiales Biocompatibles , Boro , Dentina , Hidrogeles , Nanopartículas , Alginatos/química , Humanos , Boro/química , Materiales Biocompatibles/química , Dentina/efectos de los fármacos , Porosidad , Supervivencia Celular/efectos de los fármacos , Regeneración/efectos de los fármacos , Ensayo de Materiales , Espectroscopía Infrarroja por Transformada de Fourier , Pulpa Dental/citología , Pulpa Dental/efectos de los fármacos , Microscopía Electrónica de Rastreo , Endodoncia Regenerativa/métodos , Vidrio/química , Fibroblastos/efectos de los fármacos , Cerámica/química , Agua/químicaRESUMEN
In this study, we conducted two heat treatment processes, namely double aging (DA) and solid solution followed by double aging (SA), on the Inconel 718 alloy fabricated by selective laser melting (SLM). The aim was to investigate the microstructure evolution and mechanical properties of Inconel 718 under different heat treatment conditions. To achieve this, we employed advanced techniques such as Scanning Electron Microscope (SEM), electron backscattered diffraction (EBSD), energy dispersive spectroscopy (EDS), x-ray diffraction (XRD), Tofwerk time-of-flight secondary ion mass spectrometer (TOF-SIMS), and transmission electron microscopy (TEM). Our experimental findings reveal the presence of cellular high-density dislocation substructures in the as-received (AR) specimens, with a significant accumulation of Laves phase precipitates at grain boundaries and subgrain boundaries. After the DA treatment, the cellular substructure persists, with higher concentrations of γ" and γ' strengthened phases compared to AR specimen. Conversely, the SA specimen undergoes almost complete recrystallization, resulting in the dissolution of brittle Laves phases and a substantial increase in the content of strengthening phase γ'' and γ'. As a consequence of the precipitation of the γ'' and γ' strengthened phase and the modification of the microstructure, the material exhibits enhanced strength and hardness, albeit at the expense of reduced plasticity. The investigation of the relationship between heat treatment processes and precipitation behavior indicates that the SA heat treatment yields favorable mechanical properties that strike a balance between strength and plasticity.
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Aleaciones , Calor , Rayos Láser , Aleaciones/química , Ensayo de Materiales , Difracción de Rayos X , Microscopía Electrónica de RastreoRESUMEN
Identifying evidence of human modification of extinct animal remains, such as Pleistocene megafauna, is challenging due to the similarity of anthropogenic and non-anthropogenic taphonomic features observed under optical microscopy. Here, we re-investigate a Late Pleistocene ground sloth tooth from northeast Brazil, previously suggested as human-modified based only on optical observation. To characterize the macro- and micro-morphological characteristics of the marks preserved in this tooth and evaluate potential human modification, we used stereomicroscope and scanning electron microscopy (SEM) supplemented by energy dispersive spectroscopy (EDS), UV photoluminescence (UV/PL), synchrotron-based X-ray fluorescence (SR-XRF), and synchrotron micro-computed tomography (SR-µCT). These methods allowed us to discriminate non-anthropogenic taphonomic features (root and sedimentary damage), anthropogenic marks, and histological features. The latter shows the infiltration of exogenous elements into the dentine from the sediments. Our evidence demonstrates the sequence of anthropogenic and non-anthropogenic taphonomic modification of this tooth and supports its initial intentional modification by humans. We highlight the benefits of emerging imaging and spectral imaging techniques to investigate and diagnose human modification in fossil and archaeological records and propose that human modification of tooth tissues should be further considered when studying possibly anthropogenically altered fossil remains.
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Fósiles , Perezosos , Diente , Microtomografía por Rayos X , Brasil , Diente/anatomía & histología , Animales , Humanos , Microscopía Electrónica de Rastreo , Espectrometría por Rayos XRESUMEN
Scanning Electron Microscope (SEM) is a crucial tool for studying microstructures of ceramic materials. However, the current practice heavily relies on manual efforts to extract porosity from SEM images. To address this issue, we propose PSTNet (Pyramid Segmentation Transformer Net) for grain and pore segmentation in SEM images, which merges multi-scale feature maps through operations like recombination and upsampling to predict and generate segmentation maps. These maps are used to predict the corresponding porosity at ceramic grain boundaries. To increase segmentation accuracy and minimize loss, we employ several strategies. (1) We train the micro-pore detection and segmentation model using publicly available Al2O3 and custom Y2O3 ceramic SEM images. We calculate the pixel percentage of segmented pores in SEM images to determine the surface porosity at the corresponding locations. (2) Utilizing high-temperature hot pressing sintering, we prepared and captured scanning electron microscope images of Y2O3 ceramics, with which a Y2O3 ceramic dataset was constructed through preprocessing and annotation. (3) We employed segmentation penalty cross-entropy loss, smooth L1 loss, and structural similarity (SSIM) loss as the constituent terms of a joint loss function. The segmentation penalty cross-entropy loss helps suppress segmentation loss bias, smooth L1 loss is utilized to reduce noise in images, and incorporating structural similarity into the loss function computation guides the model to better learn structural features of images, significantly improving the accuracy and robustness of semantic segmentation. (4) In the decoder stage, we utilized an improved version of the multi-head attention mechanism (MHA) for feature fusion, leading to a significant enhancement in model performance. Our model training is based on publicly available laser-sintered Al2O3 ceramic datasets and self-made high-temperature hot-pressed sintered Y2O3 ceramic datasets, and validation has been completed. Our Pix Acc score improves over the baseline by 12.2%, 86.52 vs. 76.01, and the mIoU score improves from by 25.5%, 69.10 vs. 51.49. The average relative errors on datasets Y2O3 and Al2O3 were 6.9% and 6.36%, respectively.
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Cerámica , Aprendizaje Profundo , Microscopía Electrónica de Rastreo , Cerámica/química , Porosidad , Calor , Óxido de Aluminio/químicaRESUMEN
During the investigation of firearm-related incidents, gunshot residues (GSR) can be collected on the scene and individuals (e.g., shooters or bystanders). Their analysis can give valuable information for the reconstruction of the events. Since GSR collection on persons of interest generally occurs a few minutes to hours after discharge, knowledge is needed to understand how organic (O), and inorganic (I) residues are transferred and persist. In this research, the quantities of OGSR and IGSR were assessed on the right and left hands, forearms, face, and nostrils of four shooters. Specimens were collected immediately before the discharge (shooter's blank specimens) and shortly after (30 min) using carbon adhesive stubs. Organic compounds were first extracted from the collection device and analysed using ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Subsequently, IGSR particles were detected on the same stub using scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM/EDS). Shooter's blank specimen analysis revealed background contamination of both O and IGSR in the shooter's environment, predominantly attributed to the presence of an indoor shooting range. However, the background quantities generally remained below the associated 30-minute specimen. Thirty minutes after a discharge, higher quantities were generally detected on the shooter's right and left hands than on other collection regions for both GSR types. Forearms and face emerged as interesting collection alternatives, especially in cases where a person of interest may have washed their hands in the interval between the discharge and collection. In contrast, very low amounts of GSR were detected in the nostrils. Furthermore, the results indicated that OGSR and IGSR have different transfer and persistence mechanisms.
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Armas de Fuego , Balística Forense , Mano , Humanos , Balística Forense/métodos , Cara/anatomía & histología , Microscopía Electrónica de Rastreo , Espectrometría por Rayos X , Nariz , Antimonio/análisis , Antebrazo , Espectrometría de Masas en Tándem , Bario/análisis , Heridas por Arma de Fuego , Cromatografía Líquida de Alta Presión , CiclohexanonasRESUMEN
BACKGROUND: Partial coverage concepts have met the main goal of conservative dentistry. Vonlays, which combine features of veneers and onlays, are a recent alternative to full coverage designs and overlay partial coverage restorations. This in vitro study was conducted to compare the fracture resistance of the newly introduced pressable zirconia-reinforced lithium silicate with pressable lithium disilicate ceramic and to determine the optimal preparation design for partial coverage on upper premolars. METHODS: Fifty-two duplicated epoxy resin dies were prepared following vonlay and overlay preparation guidelines. For each preparation (n = 26), the specimens were divided into two subgroups to be restored with lithium disilicate (IPS e.max Press) or zirconia-reinforced lithium silicate (Vita Ambria) (n = 13 each). Ceramic vonlays and overlays were bonded using dual cure resin cement, subjected to thermomechanical fatigue, and the load to fracture was tested by using a universal testing machine. The specimens were fractographically analyzed via scanning electron microscopy (SEM). The normality of the fracture resistance data was checked using the ShapiroâWilk test and QâQ plots, and two-way ANOVA was used to assess the effect of the type of preparation and ceramic material on the fracture resistance. RESULTS: The group of overlays restored with zirconia-reinforced lithium silicate showed the highest mean fracture load (1218.69 N), while the group of vonlays restored with lithium disilicate had the lowest mean fracture resistance (967.15 N). The effect of preparation design and material type on fracture resistance was significant for both factors, p = 0.003 and p < 0.0001, respectively. Different features of the fracture surfaces, such as arrest lines, hackles, and directions of crack propagation, were observed. CONCLUSIONS: Zirconia-reinforced lithium silicate exhibited greater resistance to fracture compared to lithium disilicate, making it a potential substitute for partial coverage restorations. Additionally, the overlay showed superior fracture resistance when compared to the vonlay preparation design.
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Diente Premolar , Cerámica , Porcelana Dental , Análisis del Estrés Dental , Ensayo de Materiales , Circonio , Cerámica/química , Porcelana Dental/química , Circonio/química , Humanos , Técnicas In Vitro , Fracaso de la Restauración Dental , Microscopía Electrónica de Rastreo , Maxilar , Diseño de Prótesis Dental , Incrustaciones , Coronas con Frente EstéticoRESUMEN
The studies presented in this paper constitute the first scientific attempt to interpret the manner whereby notched implements made of scapulae were made and used. These implements have been found at numerous European and non-European sites, usually dated to the Neolithic-Early Iron Age (predominantly the Early Bronze Age). Research has examined these products since the beginning of the 20th century, resulting in the development of several hypotheses regarding their functions. This paper presents the analysis results of 41 such artefacts from the early Bronze Age defensive settlement in Bruszczewo (central Poland). This is the largest collection of these products from a single site worldwide. The artefacts were subjected to multi-aspect traceological tests (both technological and functional) using optical, metallographic, and scanning electron microscopes. The residues identified on their surfaces were analysed using optical microscopy and scanning electron microscopy and energy dispersive X-rays spectroscopy. Moreover, the studies reported herein involved extensive experimental research. Consequently, the chain of operations followed in producing these tools was reconstructed and the use-wear traces present on their surfaces were classified; it was determined that these tools were most likely used for threshing cereals but might also have been used for threshing legumes. This is the first proof of threshing in central Europe in the Early Bronze Age and the first scientifically substantiated hypothesis regarding the function of these important artefacts.
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Arqueología , Grano Comestible , Microscopía Electrónica de Rastreo , Grano Comestible/química , Historia Antigua , Fabaceae/química , Europa (Continente) , Polonia , Humanos , Espectrometría por Rayos XRESUMEN
Nickel-titanium (NiTi) instruments offer many advantages during endodontic instrumentation; however, the fracture risk within the canal remains a concern. Manufacturers continuously develop and introduce instruments to the market with supposedly enhanced cyclic fatigue resistance and increased flexibility, achieved through different proprietary manufacturing processes, the details of which have not been made public. In recent years, two rotary systems specially designed for deciduous teeth have been commercially available, but information about their performance is lacking. This investigation aimed to identify which manufacturing process provides better cyclic fatigue resistance: the AF-H Wire technology used in the AF baby rotary files (AF-f) or the CM-Wire technology used in the i3 Gold deciduous teeth rotary files (i3G-f). Forty rotary International Organization for Standardization (ISO) 25/04 files were tested in artificial canals with a standard geometry of 60° angle and 2.5 mm radius until fracture. The number of cycles to fracture was calculated, and the length of the fragments was measured. A scanning electron microscope (SEM) was used to examine the fracture surfaces and fragments. Energy dispersive spectroscopy (EDS) was used to determine the percentage weight of NiTi in each file. The statistical analysis (Mann-Whitney test) showed that the cyclic fatigue resistance of the AF-f was significantly higher (p < 0.0001) than that of the i3G-f. Additionally, there was a significant difference (p = 0.0419) in the length of the fractured fragments. All instruments showed one or more types of manufacturing defects and presented similar NiTi percentages by weight. The manufacturing process is critical to cyclic fatigue resistance, and there seems to be responsible for the difference in cyclic fatigue resistance between these similar instruments.
Asunto(s)
Falla de Equipo , Calor , Níquel , Preparación del Conducto Radicular , Titanio , Preparación del Conducto Radicular/instrumentación , Níquel/química , Humanos , Titanio/química , Diseño de Equipo , Ensayo de Materiales , Instrumentos Dentales , Microscopía Electrónica de Rastreo , Aleaciones Dentales/química , Técnicas In Vitro , Análisis del Estrés DentalRESUMEN
To investigate the effects of lactic acid etching on the immediate and aged bond strength of the resin-dentin bonding interface, the resin-dentin bonding interface was evaluated 24 hours and 6 months later. A total of 42 isolated third molars were randomly divided into 6 experimental groups according to different lactate concentration (35%, 40%, 45%) and acid etching time (30 s, 45 s), with 37% phosphoric acid etching 15 s as a control. In each group, dentin samples were etched under different acidic conditions and bonded with Adper Single Bond 2 (3M ESPE) as directed. The immediate group was immediately stored in deionized water at 37 °C for 24 h, and the aging group was stored in artificial saliva at 37 °C for 6 months. Immediate and aged bond strengths were measured by a micro-tensile tester, and the specimen fracture surface was observed under a microscope. 14 isolated third molars were randomly divided into 7 groups, and each group was etched with acid. Collagen fibers morphology in dentin was examined after gradient dehydration with ethanol by scanning electron microscopy (SEM). Statistically, there was no difference between the resin-dentin immediate bonding strength of 35% lactic acid for 30 s and 37% phosphoric acid for 15 s, but the aged bond strength was greater than that of the phosphoric acid group. According to scanning electron microscope observations, the collagen fiber morphology in 35% and 40% lactate etching dentin 30 s groups was relatively intact compared with other groups. In conclusion, 35% lactic acid etching of dentin 30 s ensures both immediate and aged resin-dentin bond strength.