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1.
Bol. latinoam. Caribe plantas med. aromát ; 20(3): 226-243, may. 2021. ilus, tab
Article in English | LILACS | ID: biblio-1342815

ABSTRACT

Several species of the Myrcia genus have been used in folk medicine to treat diabetes. Therefore, the aim of this work was to investigate the inhibitory activity of α-glucosidase and pancreatic lipase in the crude extract (EBF) and in the ethyl acetate fraction (FFA) of Myrcia hatschbachii, as well as to identify isolated phenolic compounds and to evaluate the antioxidant property and preliminary in vitro toxicity against Artemia salina. EBF (IC50: 3.21 µg/mL) and FFA (IC50: 1.14 µg/mL) showed inhibitory activity superior to acarbose (IC50: 193.65 µg/mL). In addition, they showed inhibitory effects of pancreatic lipase (IC50: 556.58 µg/mL for EBF and 532.68 µg/mL for FFA), antioxidant potential, absence of preliminary toxicity and presence of gallic andellagic acids in FFA. The relevant results in the inhibition of α-glucosidase and pancreatic lipase motivate new studies for the development of herbal medicines that assist in the treatment of diabetic patients.


Varias especies del género Myrcia se han utilizado en la medicina popular para tratar la diabetes. Por lo tanto, el objetivo de este trabajo fue investigar la actividad inhibitoria de la α-glucosidasa y la lipasa pancreática en el extracto crudo (EBF) y en la fracción de acetato de etilo (FFA) de Myrcia hatschbachii, así como identificar compuestos fenólicos aislados y evaluar la propiedad antioxidante y toxicidad in vitro preliminar contra Artemia salina. EBF (IC50: 3.21 µg/mL) y FFA (IC50: 1.14 µg/mL) mostraron una actividad inhibitoria superior a la acarbosa (IC50: 193.65 µg/mL). Además, mostraron efectos inhibitorios de la lipasa pancreática (IC50: 556.58 µg/mL para EBF y 532.68 µg/mL para FFA), potencial antioxidante, ausencia de toxicidad preliminar y presencia de ácidos gálico y elágico en FFA. Los resultados relevantes en la inhibición de la α-glucosidasa y la lipasa pancreática motivan nuevos estudios para el desarrollo de medicamentos a base de hierbas que ayudan en el tratamiento de pacientes diabéticos.


Subject(s)
Plant Extracts/pharmacology , Myrtaceae/chemistry , Glycoside Hydrolase Inhibitors/pharmacology , Lipase/drug effects , Antioxidants/pharmacology , Pancreas/enzymology , Phenols/analysis , X-Ray Diffraction , In Vitro Techniques , Plant Extracts/toxicity , Plant Extracts/chemistry , Free Radical Scavengers , Complex Mixtures , Ellagic Acid , Gallic Acid , Antioxidants/chemistry
2.
Braz. dent. sci ; 24(2): 1-9, 2021. tab, ilus
Article in English | LILACS, BBO | ID: biblio-1177588

ABSTRACT

Objective: The purpose of the present study was to synthesize and characterize lithium disilicate glass-ceramics through the Li2O-SiO2system for determining the most satisfactory sintering parameter by evaluating the crystalline composition, microstructure and mechanical properties. Material and methods: The glass-ceramics were prepared from a glass precursor by means of the melting/cooling technique with a composition of 33.33 Li2O and 66.67 SiO2 (mol.%). The specimens were compressed by the uniaxial pressing technique and three different thermal treatments were used for sintering: 850 °C (Group 1), 900 °C (Group 2), and 950 °C (Group 3), which were determined based on the differential scanning calorimetry (DSC) result. The glass-ceramics were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Archimedes method, microhardness and biaxial flexural strength analyses. Results: The results regarding XRD predominantly showed lithium disilicate phase for all the heat treatments performed. Moreover, grains with a needle form were more predominantly observed in the SEM images for Group 3, as well as a higher densification and consequently higher mechanical properties. In contrast, Group 1 presented the lowest mechanical properties and densification, as well as the highest porosity. Conclusion: The present study demonstrated how extremely important it is to follow the heat treatment recommended by the manufacturers of ceramics, including time and temperature, which possess direct effects in the crystalline phase formation, as well as in the material's microstructure and mechanical properties (AU)


Objetivo: O presente estudo teve como objetivo sintetizar e caracterizar uma vitrocerâmica de dissilicato de lítio através do sistema Li2O-SiO2para determinar o parâmetro de sinterização mais satisfatório através da avaliação da composição cristalina, microestrutura e propriedades mecânicas. Material e Métodos: As vitrocerâmicas foram preparadas a partir de um vidro precursor pelo método fusão/resfriamento utilizando a composição de 33.33 Li2O e 66.67 SiO2 (mol.%). As amostras foram prensadas utilizando uma técnica de prensagem uniaxial e três tratamentos térmicos diferentes foram utilizadas para sinterização: 850 °C (Grupo 1), 900 °C (Grupo 2), e 950 °C (Grupo 3), que foram determinados através do resultado da análise diferencial de calorimetria. As vitrocerâmicas foram caracterizadas através das análises de difração de raios X (DRX), microscopia eletrônica de varredura (MEV), métodos de Arquimedes, microdureza e ensaio de flexão biaxial. Resultados: Os resultados de DRX mostraram predominantemente a fase de dissilicato de lítio para todos os tratamentos realizados. Além disso, grãos com forma agulhada foram mais predominantemente observados por MEV no grupo 3, assim como uma densificação maior e consequentemente valores maiores das propriedades mecânicas. Em contraste, o grupo 1 apresentou os menores valores de propriedades mecânicas e densificação, e também a maior porosidade. Conclusão: O presente estudo demonstrou como é extremamente importante seguir o tratamento térmico recomendado pelos fabricantes de cerâmica, incluindo tempo e temperatura, que possuem efeitos diretos na formação da fase cristalina, assim como na microestrutura do material e propriedades mecânicas. (AU)


Subject(s)
X-Ray Diffraction , Microscopy, Electron, Scanning , Crystallization
3.
Braz. dent. sci ; 24(3): 1-9, 2021. tab, ilus, graf
Article in English | LILACS, BBO | ID: biblio-1281728

ABSTRACT

Objective: The present study aimed to evaluate the effect of repressing and different surface treatment protocols on the shear bond strength of lithium disilicate glass-ceramics. Material and Methods: A total of 52 lithium disilicate glass-ceramic discs (IPS emax Press, Ivoclar Vivadent) were fabricated using the heat-press technique. The discs were divided into two groups; group (P): discs fabricated from new e.max ingots (n=26), group (R): discs fabricated from reused e.max buttons (n=26). Each group was subdivided into subgroup (E): discs were etched with hydrofluoric acid (9.5%) (n=13), subgroup (S): discs were air-abraded with 110 µm alumina particles. All specimens were subjected to X-ray Diffraction analysis, Scanning Electron Microscope, Energy Dispersive X-Ray, Thermo-Cycling, and Shear Bond Strength Testing. Results: Repressed Etched subgroup (RE) recorded the statistically highest shear bond strength value, followed by the Pressed Etched subgroup (PE), while the statistically lowest shear bond strength value was recorded for the Pressed Air-Abraded subgroup (PS) and Repressed Air-Abraded subgroup (RS). Conclusion: Repressing the leftover buttons for the construction of new lithium disilicate glass-ceramic restorations has no adverse effect on the bond strength of the resin cement to the ceramic. Hydrofluoric acid surface treatment improves the shear bond strength and durability of resin cement bond to both pressed and repressed lithium disilicate glass-ceramic. Air-abrasion cannot be considered as a reliable surface treatment when bonding to lithium disilicate glass-ceramics. (AU)


Objetivo: O presente estudo teve como objetivo avaliar o efeito da reprensagem e de diferentes protocolos de tratamento de superfície na resistência ao cisalhamento de vitrocerâmica de dissilicato de lítio. Materiais e Métodos: Um total de 52 discos de vitrocerâmica de dissilicato de lítio (IPS emax Press, Ivoclar Vivadent) foram fabricadas usando a técnica de prensagem quente. Os discos foram divididos em dois grupos: grupo (P): discos fabricados a partir de novo lingotes de e-max (n=26), grupo (R): discos fabricados a partir de botões de emax reutilizados (n=26). Cada grupo foi subdividido em subgrupo (E): discos condicionados com ácido fluorídrico (9,5%) (n=13), subgrupo (S) discos foram abrasivos com partícula 110 µm de alumínio. Todos os espécimes foram submetidos a analise de difração de raio-x, microscópio eletrônico de varredura, raio-x de energia dispersiva, termociclagem e teste de resistência de cisalhamento. Resultados: O subgrupo Reprensado-condicionado (RE) registrou o valor estatisticamente mais alta em relação a resistência ao cisalhamento, seguido pelo subgrupo Prensado-condicionado (PE), enquanto o valor estatisticamente mais baixo de resistência ao cisalhamento foi o subgrupo Prensado-Jateado (OS) e o subgrupo Reprensado-Jateado (RS). Conclusão: A reprensagem dos botões restantes para a construção de novas restaurações vitrocarâmicas de dissilicato de lítio não apresentou efeitos adversos na resistência de unicãp do cimento resinoso à cerâmica. O tratamento de superfície com ácido fluorídrico melhora a resistência ao cisalhamento e a durabilidade do cimento resinoso para vitrocerâmica de dissilicato de lítio prensada e reprimida. A abrasão por ar não pode ser considerada um tratamento de superfície confiável quanto a colagem da vitrocerâmica de dissilicato de lítio (AU)


Subject(s)
X-Ray Diffraction , Resin Cements , Shear Strength , Microscopy, Electrochemical, Scanning
4.
Article in English | WPRIM | ID: wpr-811435

ABSTRACT

PURPOSE: The aim of this study was to investigate the effect of different numbers of heat treatments applied to superstructure porcelain on optical, thermal, and phase formation properties of zirconia.MATERIALS AND METHODS: Forty zirconia specimens were prepared in the form of rectangular prism. Specimens were divided into four groups (n = 10) according to the number of firing at heating values of porcelain. Color differences and translucency parameter were measured, and X-ray diffraction (XRD) analysis and differential scanning calorimetry (DSC) were performed. Data were analyzed with analysis of variance (ANOVA).RESULTS: There were no statistically significant differences in ΔE, TP, L, a, and b value changes of the zirconia specimens as a result of repetitive firing processes (P>.05).CONCLUSION: Although additional firing processes up to 4 increase peak density in thermal analysis, additional firing processes up to 4 times can be applied safely as they do not result in a change in color and phase character of zircon frameworks.


Subject(s)
Calorimetry, Differential Scanning , Dental Porcelain , Fires , Heating , Hot Temperature , X-Ray Diffraction
5.
J. appl. oral sci ; 28: e20190371, 2020. tab, graf
Article in English | LILACS, BBO | ID: biblio-1056595

ABSTRACT

Abstract Objective This study aims to evaluate the influence of different air-abrasion pressures and subsequent heat treatment on the flexural strength, surface roughness, and crystallographic phases of highly translucent partially stabilized zirconia (Y-PSZ), and on the tensile bond strength of resin cement to Y-PSZ. Methodology Fully sintered zirconia specimens were ground with SiC paper (control) and/or air-abraded with 50 µm particles of alumina at 0.1, 0.15, 0.2, or 0.3 MPa or left as-sintered. After air-abrasion at 0.2 MPa (0.2AB), additional specimens were then heated to 1500°C, and held for one hour at this temperature (0.2AB+HT1h). Flexural strength and surface roughness were evaluated. Crystalline phase identification was also carried out using X-ray diffraction. Bonded zirconia specimens with self-adhesive resin cement were stored in distilled water at 37°C for 24 h, either with or without aging (thermal cycling 4-60°C/20000). Results were analyzed statistically by ANOVA and Tukey-Kramer tests. Results The flexural strength decreased with the increase in air-abrasion pressure, while in contrast, the surface roughness increased. The lowest flexural strength and the highest roughness value were found for the 0.2AB and 0.3AB groups, respectively. All groups contained cubic-, tetragonal ( t )-, and rhombohedral ( r )-ZrO2 phases with the exception of the as-sintered group. Upon increasing the air-abrasion pressure, the relative amount of the r -ZrO2 phase increased, with a significant amount of r -ZrO2 phase being detected for the 0.2AB and 0.3AB groups. The 0.2AB+HT1h group exhibited a similar flexural strength and t -ZrO2 phase content as the as-sintered group. However, the 0.2AB group showed a significantly higher tensile bond strength (p<0.05) than the 0.2AB+HT1h group before and after aging. Conclusion Micromechanical retention by alumina air-abrasion at 0.2 MPa, in combination with chemical bonding of a resin to highly translucent Y-PSZ using a MDP-containing resin cement may enable durable bonding.


Subject(s)
Zirconium/chemistry , Dental Bonding/methods , Resin Cements/chemistry , Air Abrasion, Dental/methods , Aluminum Oxide/chemistry , Reference Values , Surface Properties , Tensile Strength , X-Ray Diffraction/methods , Materials Testing , Reproducibility of Results , Analysis of Variance , Microscopy, Confocal/methods , Flexural Strength , Hot Temperature
6.
Braz. oral res. (Online) ; 34: e004, 2020. tab, graf
Article in English | LILACS | ID: biblio-1055523

ABSTRACT

Abstract The aim of this study was to analyze the structural, morphological and mechanical properties of two different lithium disilicate glass-reinforced ceramics for CAD-CAM systems (IPS e.max CAD and Rosetta SM). Five methodologies were used for both ceramics: microstructure (n = 2) was analyzed using x-ray diffraction (XRD); morphological properties (n = 2) were analyzed by scanning electron microscopy (SEM), with and without hydrofluoric etching; porosity (n = 3) was assessed using 3D micro-computed tomography (micro-CT); flexural strength was measured (n =1 0) using the three-point bending test; and bond strength was determined with self-adhesive resin cement (n = 10), using a microshear bond test. After performing all the tests, the data were analyzed using t-Student test and two-way ANOVA. All the tests used a significance level of α = 0.05. High peak positions corresponding to standard lithium metasilicate and lithium disilicate with similar intensities were observed for both ceramics in the XRD analysis. Morphological analysis showed that the crystalline structure of the two ceramics studied showed no statistical difference after acid etching. Additionally, no significant differences were recorded in the number or size of the pores for the ceramics evaluated. Moreover, no differences in flexural strength were found for the ceramic materials tested, or in the bond strength to ceramic substrates for the resin cements. Based on the study results, no significant differences were found between the two CAD-CAM lithium disilicate glass-reinforced ceramics tested, since they presented similar crystalline structures with comparable intensities, and similar total porosity, flexural strength and bond strength.


Subject(s)
Ceramics/chemistry , Computer-Aided Design , Dental Porcelain/chemistry , Glass/chemistry , Reference Values , Surface Properties , X-Ray Diffraction , Materials Testing , Microscopy, Electron, Scanning , Reproducibility of Results , Analysis of Variance , Porosity , Dental Bonding/methods , Resin Cements/chemistry , Shear Strength , Flexural Strength
7.
Braz. dent. j ; 30(5): 453-458, Sept.-Oct. 2019. graf
Article in English | LILACS | ID: biblio-1039141

ABSTRACT

Abstract The aim of this study was to analyze the effects of MTA on the structure and enzymatic activity of sPLA2 in order to provide subsidies for improvement in the formulation of the product. MTA powder was incubated for 60 min in the presence of sPLA2 and was analyzed by chromatography, electrospray mass (ESI-MS) and small-angle X-ray scattering (SAXS). It was find that the elution profile, retention time, and fragmentation of sPLA2 were altered after treatment with MTA. Calcium was the MTA component that most amplified the inflammatory signal. Significant interactions were found between MTA and sPLA2, which could aid in our understanding of the mechanisms of action of MTA during the inflammatory process and it may facilitate the structural modification of MTA, thereby improving its biological safety and consequently the rate of the treatment success.


Resumo O objetivo deste estudo foi analisar os efeitos do MTA na estrutura e atividade enzimática da sPLA2 a fim de fornecer subsídios para melhoria na formulação do produto. O MTA em pó foi incubado por 60 min na presença de sPLA2 e analisado por cromatografia, espectroscopia de massa por eletropulverização (ESI-MS) e espalhamento de raios-X de baixo ângulo (SAXS). Encontrou-se que o perfil de eluição, o tempo de retenção e a fragmentação da sPLA2 foram alterados após o tratamento com MTA. O cálcio foi o componente do MTA que mais ampliou o sinal inflamatório. Encontraram-se interações significativas entre o MTA e o sPLA2, o que poderia auxiliar na compreensão dos mecanismos de ação do MTA durante o processo inflamatório e facilitar a modificação estrutural do MTA, melhorando sua segurança biológica e consequentemente a taxa de sucesso do tratamento.


Subject(s)
Root Canal Filling Materials , Oxides , X-Ray Diffraction , Silicates , Calcium Compounds , Aluminum Compounds , Drug Combinations , Scattering, Small Angle
8.
Rev. biol. trop ; 67(1): 83-93, Jan.-Mar. 2019. tab, graf
Article in English | LILACS | ID: biblio-1041896

ABSTRACT

Abstract The solubility equilibrium of calcite is influenced by physicochemical, climatic and biological factors. Annual cycles of exceptionally prolonged drought, in conjunction with naturally occurring diffuse organic pollution, generate the unique conditions for the precipitation of lithified carbonate structures (microbialites). The aim of this article is to analyze the possible implications of calcite precipitation produced in mats of Cladophora sp. in an Andean subtropical basin, considering it is the first time this phenomenon is described for the region. We collected samples from selected sites at the Lules River Basin, in four sampling dates between the years 2003 and 2004, within a monitoring work of 15 years. Samples were analyzed using an electron microscope and X-ray diffraction analysis. We found that Gomphonema sp. attached to Cladophora sp. contributes to precipitation of calcite and formation of microbialite like structures, in the studied area. This work presents an initial discussion of the discovery of microbialites-like structures attached to Cladophora sp. mats in a subtropical Andean stream and the environmental conditions that lead to their production, as well as the possible ecological implications of these microbialites.(AU)


Resumen La fase sólida de las sales de los cuerpos de agua juega un papel importante en la concentración de los elementos mayoritarios. El equilibrio de solubilidad de la calcita está influenciado por factores fisicoquímicos, climáticos y biológicos. Los ciclos anuales de sequía excepcionalmente prolongada, junto con la contaminación orgánica difusa de origen natural, generan condiciones únicas para la precipitación de estructuras de carbonato litificado (microbialitos). El objetivo de este artículo es analizar las posibles implicaciones de la precipitación de calcita producida en Cladophora sp. en una cuenca subtropical andina, considerando que es la primera vez que se describe este fenómeno para la región. Recolectamos muestras en sitios seleccionados en la Cuenca del Río Lules, en cuatro fechas de muestreo entre 2003 y 2004, en el marco de un trabajo de monitoreo de quince años. Usamos red Surber para realizar los muestreos. Las muestras de algas, una vez libres de macroinvertebrados, se secaron y pesaron. Analizamos utilizando microscopía electrónica y difracción de rayos X. Encontramos que Gomphonema sp. unido a Cladophora contribuye a la precipitación de calcita y la formación de estructuras similares a microbialitos, en el área estudiada. Este trabajo presenta una discusión inicial sobre el descubrimiento de estructuras similares a microbialitos unidas a filamentos de Cladophora sp. en una cuenca andina subtropical y las condiciones ambientales que conducen a su producción, así como las posibles implicaciones ecológicas de lo mencionado anteriormente.(AU)


Subject(s)
Lithium Carbonate/analysis , Diatoms/chemistry , Environmental Pollution , Droughts , Argentina , X-Ray Diffraction/instrumentation , Microscopy, Electron/instrumentation , Sampling Studies
9.
Article in Chinese | WPRIM | ID: wpr-773102

ABSTRACT

The single-factor test was used to optimize the high-pressure homogenization method to prepare the phenolic extract nanosuspensions(DBNs). The physicochemical properties of the obtained nanosuspensions were characterized and the cumulative release in vitro was evaluated. The results showed that the drug concentration was 0.5 g·L~(-1), the mass concentrations of PVPK30 and SDS were 0.5 and 0.25 g·L~(-1), respectively, the probe ultrasonic time was 5 min, the homogenization pressure was 900 bar, and the number of homogenization was 2 times. The prepared DBNs had an average particle size of(168.80±0.36) nm, polydispersity index(PDI) of 0.09±0.04, stability index(SI) of 0.85, and DBNs were stable for storage within 30 days. Scanning electron microscopy showed that the particle size of the dragon's blood extract was reduced and the uniformity was improved in the obtained nanosuspensions. X-ray diffraction pattern and differential scanning calorimetry showed that the phenolic extract of dragon's blood was still in an amorphous state after being prepared into nanosuspensions. The results of saturated solubility measurement showed that the solubility of DBNs lyophilized powder reached 6.25 g·L~(-1), while the solubility of DB raw powder was only 28.67 mg·L~(-1). The in vitro dissolution experiments showed that DBNs lyophilized powder accumulated in gastrointestinal fluid for 8 h. The release amount was 90%,the cumulative release of the raw powder in the gastrointestinal fluid for 24 h was less than 1%, and the solubility and dissolution rate of the DBNs lyophilized powder were significantly higher than the DB raw powder. The method is simple in process and convenient in operation, and can successfully prepare uniform and stable nanosuspensions to improve its solubility, and provides a research basis for solving the application limitation of dragon's blood extract.


Subject(s)
Calorimetry, Differential Scanning , Nanoparticles , Particle Size , Plant Extracts , Chemistry , Solubility , Suspensions , X-Ray Diffraction
10.
Article in Chinese | WPRIM | ID: wpr-777475

ABSTRACT

The powder X-ray diffraction(PXRD) technique was used to investigate fourteen kinds of Ranunculaceae herbal decoction pieces(RHDP) recorded in Chinese Pharmacopoeia and to explore a novel PXRD quality control method for RHDP. The results indicated that only three RHDP-Paeoniae Radix Alba, Paeoniae Radix Rubra, and Moutan Cortex, contained calcium oxalate monodydrate(COM), whereas no COM existed in other eleven kinds of RHDP. The difference in PXRD for Paeoniae Radix Alba and Paeoniae Radix Rubra from different growing areas were investigated. The quantitative analysis method for COM was discussed by considering the water-boiling manufacturing process of herbal decoction pieces. The water-boiling experiments revealed that the PXRD peaks from COM crystals in RHDP were enhanced significantly after boiling. Paeoniae Radix Alba, Paeoniae Radix Rubra, Moutan Cortex, Aconiti Lateralis Radix Praeparata, Aconiti Radix, Aconiti Kusnezoffii Radix, and Anemone Raddeanae Rhizoma exhibited a similar series of broader peaks in the 2θ region of 15° to 35°, whose origins were discussed on the basis of chemical constituents RHDP reported by other researchers. These diffraction broader peaks most likely originated from periodic orientation of benzene ring in organic molecular crystals of aconitine-and paeonolum-based alkaloids and glycosides chemical constituents, subsequently, possibly from some other organic constituents. The PXRD technique can be used to rapidly identify Cimicifuga heracleifolia with an amorphous dispersion peak and C. dahurica with a sharp-peak feature. Climatidis Radix et Rhizoma exhibited a series of sharp PXRD peaks. The PXRD method can provide a valuable quality control method for RHDP.


Subject(s)
Aconitum , Chemistry , Drugs, Chinese Herbal , Chemistry , Paeonia , Chemistry , Phytochemicals , Ranunculaceae , Chemistry , Rhizome , Chemistry , X-Ray Diffraction
11.
Article in English | WPRIM | ID: wpr-742083

ABSTRACT

PURPOSE: The purpose of this study was to evaluate the effects of various protocols and systems for finishing and polishing monolithic zirconia on surface topography, phase transformation, and bacterial adhesion. MATERIALS AND METHODS: Three hundred monolithic zirconia specimens were fabricated and then treated with three finishing and polishing systems (Jota [JO], Meisinger [ME], and Edenta [ED]) using four surface treatment protocols: coarse finishing alone (C); coarse finishing and medium polishing (CM); coarse finishing and fine polishing (CF); and coarse finishing, medium polishing, and fine polishing (CMF). Surface roughness, crystal phase transformation, and bacterial adhesion were evaluated using atomic force microscopy, X-ray diffraction, and streptococcal biofilm formation assay, respectively. One-way and two-way analysis of variance with Tukey post hoc tests were used to analyze the results (α=.05). RESULTS: In this study, the surface treatment protocols and systems had significant effects on the resulting roughness. The CMF protocol produced the lowest roughness values, followed by CM and CF. Use of the JO system produced the lowest roughness values and the smallest biofilm mass, while the ME system produced the smallest partial transformation ratio. The ED group exhibited the highest roughness values, biofilm mass, and partial transformation ratio. CONCLUSION: Stepwise surface treatment of monolithic zirconia, combined with careful polishing system selection, is essential to obtaining optimal microstructural and biological surface results.


Subject(s)
Bacterial Adhesion , Biofilms , Clinical Protocols , Dental Polishing , Microscopy, Atomic Force , X-Ray Diffraction
12.
Article in English | WPRIM | ID: wpr-759675

ABSTRACT

There has been increasing use of the H₂O₂-based teeth bleaching agents. The purpose of this study was to evaluate the bleaching effectiveness of the laser irradiation combined with nitrogen doped-TiO₂ nanoparticles (NPs) on the stained resin. Nitrogen (N) doped-TiO₂ NPs were prepared under sol-gel method. Light absorbance, X-ray diffraction patterns of NPs, and bleaching of methylene blue and stained resins were evaluated. For bleaching of stained resin, NPs-containing gel was used. For irradiation, light of two different wavelengths was used. Unlike TiO₂, N-TiO₂ showed high absorbance after 400 nm. N-TiO₂, which have used TiN as a precursor, showed a new rutile phase at the TiN structure. For methylene blue solution, N-TiO₂ with 3% H₂O₂ resulted in the greatest absorbance decrease after laser irradiation regardless of wavelength. For stained resin test, N-TiO₂ with 3% H₂O₂ resulted in the greatest color difference after laser irradiation, followed by group that used N-TiO₂ without 3% H₂O₂.


Subject(s)
Methods , Methylene Blue , Nanoparticles , Nitrogen , Tin , Tooth Bleaching Agents , X-Ray Diffraction
13.
Article in English | WPRIM | ID: wpr-764043

ABSTRACT

In the present study, rutile phase titanium dioxide nanoparticles (R-TiO₂ NPs) were prepared by hydrolysis of titanium tetrachloride in an aqueous solution followed by calcination at 900℃. The composition of R-TiO₂ NPs was determined by the analysis of X-ray diffraction data, and the characteristic features of R-TiO₂ NPs such as the surface functional group, particle size, shape, surface topography, and morphological behavior were analyzed by Fourier-transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy, transmission electron microscopy, dynamic light scattering, and zeta potential measurements. The average size of the prepared R-TiO₂ NPs was 76 nm, the surface area was 19 m²/g, zeta potential was −20.8 mV, and average hydrodynamic diameter in dimethyl sulfoxide (DMSO)–H₂O solution was 550 nm. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and morphological observations revealed that R-TiO₂ NPs were cytocompatible with oral cancer cells, with no inhibition of cell growth and proliferation. This suggests the efficacy of R-TiO₂ NPs for the aesthetic white pigmentation of teeth.


Subject(s)
Dimethyl Sulfoxide , Dynamic Light Scattering , Hydrodynamics , Hydrolysis , Microscopy, Electron, Scanning , Microscopy, Electron, Transmission , Mouth Neoplasms , Nanoparticles , Particle Size , Pigmentation , Spectrometry, X-Ray Emission , Spectrum Analysis , Titanium , Tooth , X-Ray Diffraction
14.
J. appl. oral sci ; 27: e20180247, 2019. tab, graf
Article in English | LILACS | ID: biblio-975879

ABSTRACT

Abstract Objective This study aimed to investigate the effects of dodecacalcium hepta-aluminate (C12A7) content on some physicochemical properties and cytocompatibility of tricalcium silicate (C3S) cement using human dental pulp cells (hDPCs). Material and Methods High purity C3S cement was manufactured by a solid phase method. C12A7 was mixed with the cement in proportions of 0, 5, 8, and 10 wt% (C12A7-0, −5, −8, and −10, respectively). Physicochemical properties including initial setting time, compressive strength, and alkalinity were evaluated. Cytocompatibility was assessed with cell viability tests and cell number counts. Statistical analysis was performed by using one-way analysis of variance (ANOVA) and Tukey's test (p<0.05). Results The initial setting time of C3S-based cement was shorter in the presence of C12A7 (p<0.05). After 1 day, C12A7-5 showed significantly higher compressive strength than the other groups (p<0.05). After 7 days, the compressive strength of C12A7-5 was similar to that of C12A7-0, whereas other groups showed strength lower than C12A7-0. The pH values of all tested groups showed no significant differences after 1 day (p>0.05). The C12A7-5 group showed similar cell viability to the C12A7-0 group (p>0.05), while the other experimental groups showed lower values compared to C12A7-0 group (p<0.05). The number of cells grown on the C12A7-5 specimen was higher than that on C12A7-8 and −10 (p<0.05). Conclusions The addition of C12A7 to C3S cement at a proportion of 5% resulted in rapid initial setting time and higher compressive strength with no adverse effects on cytocompatibility.


Subject(s)
Humans , Silicates/chemistry , Calcium Compounds/chemistry , Aluminum Compounds/chemistry , Dental Cements/chemistry , Dental Pulp Cavity/cytology , Particle Size , Reference Values , Time Factors , X-Ray Diffraction , Biocompatible Materials/pharmacology , Biocompatible Materials/chemistry , Materials Testing , Microscopy, Electron, Scanning , Cell Survival/drug effects , Cells, Cultured , Reproducibility of Results , Silicates/pharmacology , Calcium Compounds/pharmacology , Aluminum Compounds/pharmacology , Compressive Strength , Dental Cements/pharmacology , Dental Pulp Cavity/drug effects
15.
Braz. arch. biol. technol ; 62: e19180266, 2019. tab, graf
Article in English | LILACS | ID: biblio-1055379

ABSTRACT

Abstract Phytochemical content of plant extracts can be used effectively to reduce the metal ions to nanoparticles in one-step green synthesis process. In this study, six plant extracts were used for the synthesis of silver nanoparticles (AgNPs). Biologically synthesized AgNPs was characterized using UV-Vis Spectrophotometer, Field Emission Scanning Electron Microscope (FE-SEM), X-ray diffraction (XRD), Energy Dispersive X-ray spectroscopy (EDX) and Fourier Transform Infrared (FTIR) spectroscopy. The individual and combined effects of AgNPs and tetracycline against S. aureus and K. pneumoniae were assessed. Ginger, onion and sidr extracts supported AgNPs formation while arak, garlic and mint extracts failed to convert the silver ions to AgNPs. The present findings revealed significant differences between the tested plant extracts in supporting AgNPs synthesis. AgNPs synthesized by ginger showed the highest individual and combined activity against tested strains followed by AgNPs prepared by sidr then that synthesized by onion. AgNPs significantly enhanced tetracycline activity (p≤0.05) against S. aureus and K. pneumoniae. The results of this study demonstrated that the combination of tetracycline and biologically synthesized AgNPs presented a useful therapeutically method for the treatment of bacterial infection and counterattacking bacterial resistance.


Subject(s)
Silver/pharmacology , Staphylococcus aureus/drug effects , Tetracycline/biosynthesis , Plant Extracts/biosynthesis , Klebsiella pneumoniae/drug effects , Spectrometry, X-Ray Emission/instrumentation , X-Ray Diffraction/instrumentation , Spectrophotometers/methods , Spectroscopy, Fourier Transform Infrared/instrumentation
16.
Article in English | WPRIM | ID: wpr-761906

ABSTRACT

BACKGROUND: Nowadays, production of nanocomposite scaffolds based on natural biopolymer, bioceramic, and metal ions is a growing field of research due to the potential for bone tissue engineering applications. METHODS: In this study, a nanocomposite scaffold for bone tissue engineering was successfully prepared using collagen (COL), beta-tricalcium phosphate (β-TCP) and strontium oxide (SrO). A composition of β-TCP (4.9 g) was prepared by doping with SrO (0.05 g). Biocompatible porous nanocomposite scaffolds were prepared by freeze-drying in different formulations [COL, COL/β-TCP (1:2 w/w), and COL/β-TCP-Sr (1:2 w/w)] to be used as a provisional matrix or scaffold for bone tissue engineering. The nanoparticles were characterized by X-ray diffraction, Fourier transforms infrared spectroscopy and energy dispersive spectroscopy. Moreover, the prepared scaffolds were characterized by physicochemical properties, such as porosity, swelling ratio, biodegradation, mechanical properties, and biomineralization. RESULTS: All the scaffolds had a microporous structure with high porosity (~ 95–99%) and appropriate pore size (100–200 µm). COL/β-TCP-Sr scaffolds had the compressive modulus (213.44 ± 0.47 kPa) higher than that of COL/β-TCP (33.14 ± 1.77 kPa). In vitro cytocompatibility, cell attachment and alkaline phosphatase (ALP) activity studies performed using rat bone marrow mesenchymal stem cells. Addition of β-TCP-Sr to collagen scaffolds increased ALP activity by 1.33–1.79 and 2.92–4.57 folds after 7 and 14 days of culture, respectively. CONCLUSION: In summary, it was found that the incorporation of Sr into the collagen-β-TCP scaffolds has a great potential for bone tissue engineering applications.


Subject(s)
Alkaline Phosphatase , Animals , Biopolymers , Bone and Bones , Bone Marrow , Collagen , Fourier Analysis , Freeze Drying , In Vitro Techniques , Ions , Mesenchymal Stem Cells , Nanocomposites , Nanoparticles , Porosity , Rats , Spectrum Analysis , Strontium , X-Ray Diffraction
17.
Article in English | WPRIM | ID: wpr-761422

ABSTRACT

PURPOSE: To evaluate the influence of cyclic loading on phase transformation of zirconia abutments and to compare the effectiveness of three different quantitative ageing assessment techniques. MATERIALS AND METHODS: Thirty two Y-TZP prostheses fabricated from two brands, InCoris ZI and Ceramill ZI, were cemented to titanium bases and equally divided into two subgroups (n=8): control group without any treatment and aged group with cyclic loading between 20 N and 98 N for 100,000 cycles at 4 Hz in distilled water at 37℃. The tetragonal-to-monoclinic phase transformation was assessed by (i) conventional x-ray diffraction (XRD), (ii) micro x-ray diffraction (µXRD), and (iii) micro-Raman spectroscopy. The monoclinic-phase fractions (M%) were compared by two-way ANOVA. RESULTS: InCoris Zi presented significantly higher M% than Ceramill Zi in both control and aged groups (P<.001). Both materials exhibited significant phase transformation with monoclinicphase of 1 to 3% more in aged groups than controls for all thre e assessment techniques. The comparable M% was quantified by both µXRD and XRD. The highest M% was assessed with micro-Raman. CONCLUSION: Cyclic loading produced significant phase transformation in tested Y-TZP prostheses. The micro-Raman spectroscopy could be used as an alternative to XRD and µXRD.


Subject(s)
Prostheses and Implants , Spectrum Analysis , Titanium , Water , X-Ray Diffraction
18.
Article in English | WPRIM | ID: wpr-750278

ABSTRACT

The calcium phosphate coating on various pretreated metals was prepared by soaking in modified simulated body fluid (m-SBF) solution. The coating structure and its surface morphologies were determined by x-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. The results revealed significant differences in morphology and composition of the calcium phosphate coatings with and without chitosan and NaOH-pretreated commercially pure titanium (cp-Ti) substrate. The calcium phosphates formed on chitosan coated-Ti pretreated with NaOH were ~ 350 nm-sized resulting in strong bonding of the apatite layer with the substrates and a uniform gradient of stress transfer from coating materials to the Ti-substrate. After NaOH pretreatment, the hydroxyl groups bind to Ca²⁺ to attract PO₄³⁻ anions, eventually resulting in a continuous layer of calcium phosphate on chitosan coated-Ti substrate during immersion in m-SBF solution. The chitosan coated-Ti showed hydrophobic surface while NaOH pretreatment resulted in maximum hydrophilicity to the Ti substrate. Due to improved wettability of Ti by NaOH pretreatment before chitosan coating, aggregation of calcium phosphate was prevented and size-controlled composite materials were obtained.


Subject(s)
Anions , Body Fluids , Calcium Phosphates , Calcium , Chitosan , Clothing , Hydrophobic and Hydrophilic Interactions , Immersion , Metals , Microscopy, Electron, Scanning , Spectroscopy, Fourier Transform Infrared , Titanium , Wettability , X-Ray Diffraction
19.
Article in English | WPRIM | ID: wpr-765145

ABSTRACT

BACKGROUND: Alendronate (AL), a drug for inhibiting osteoclast-mediated bone-resorption, was intercalated into an inorganic drug delivery nanovehicle, layered double hydroxide (LDH), to form a new nanohybrid, AL-LDH, with 1:1 heterostructure along the crystallographic C-axis. Based on the intercalation reaction strategy, the present AL-LDH drug delivery system (DDS) was realized with an enhanced drug efficacy of AL, which was confirmed by the improved proliferation and osteogenic differentiation of osteoblast-like cells (MG63). METHODS: The AL-LDH nanohybrid was synthesized by conventional ion-exchange reaction and characterized by powder X-ray diffraction (PXRD), high-resolution transmission electron microscopy (HR-TEM), and Fourier transform infrared (FT-IR) spectroscopy. Additionally, in vitro efficacy tests, such as cell proliferation and alkaline phosphatase (ALP) activity, were analyzed. RESULTS: The AL was successfully intercalated into LDH via ion-exchange reaction, and thus prepared AL-LDH DDS was X-ray single phasic and chemically well defined. The accumulated AL content in MG63 cells treated with the AL-LDH DDS nanoparticles was determined to be 10.6-fold higher than that within those treated with the intact AL after incubation for 1 hour, suggesting that intercellular permeation of AL was facilitated thanks to the hybridization with drug delivery vehicle, LDH. Furthermore, both in vitro proliferation level and ALP activity of MG63 treated with the present hybrid drug, AL-LDH, were found to be much more enhanced than those treated with the intact AL. This is surely due to the fact that LDH could deliver AL drug very efficiently, although LDH itself does not show any effect on proliferation and osteogenic differentiation of MG63 cells. CONCLUSION: The present AL-LDH could be considered as a promising DDS for improving efficacy of AL.


Subject(s)
Alendronate , Alkaline Phosphatase , Cell Proliferation , Drug Delivery Systems , Fourier Analysis , In Vitro Techniques , Microscopy, Electron, Transmission , Nanoparticles , Spectrum Analysis , X-Ray Diffraction
20.
Braz. dent. j ; 29(5): 483-491, Sept.-Oct. 2018. tab, graf
Article in English | LILACS | ID: biblio-974179

ABSTRACT

Abstract It evaluated the effect of aging by Low Temperature Degradation (LTD), executed after post- processing surface treatments (polishing, heat treatment and glazing), on the surface characteristics (micromorphology and roughness) and on the structural stability (phase transformation and mechanical behavior-flexural strength and structural reliability) of a ground yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramic. Discs of Y-TZP (VITA In-Ceram YZ) were manufactured (ISO:6872-2015; 15 mm in diameter and 1.2 ± 0.2 mm in thickness) and randomly assigned into 10 groups according two factors: "aging" in 2 levels (with or without) and "surface treatment" in 5 levels (Ctrl: as-sintered; Gr: grinding with coarse diamond bur; Gr + HT: grinding plus heat treatment; Gr + Pol: grinding plus polishing; Gr + Gl: grinding plus glazing). Roughness (n=30), biaxial flexural test (n=30), phase transformation (n=2), and surface topography (n=2) analyses were performed. Aging led to an intense increase in monoclinic (m) phase content for all the tested conditions, being the as-sintered samples (Ctrl= 65.6%) more susceptible to the t-m phase transformation. Despite of increasing the m-phase content, aging was not detrimental for characteristic strength (except to the grinding condition). There was no significant reduction in the Weibull modulus after surface treatments. Additionally, heat treatment and glazing after grinding led to a decrease in characteristic strength, while polishing presented the highest characteristic strength values. Thus, polishing is mandatory after grinding the Y-TZP ceramic, while performing glazing or heat-treatment alone after grinding lead to the worst mechanical performance.


Resumo Este estudo avaliou o efeito do envelhecimento através da degradação a baixas temperaturas (low temperaturare degradation - LTD) após a realização de tratamentos de superfície pós- sinterização (polimento, tratamento térmico e glaze) nas características superficiais (micromorfologia e rugosidade), e na estabilidade estrutural (transformação de fase e comportamento mecânico - resistência flexural e confiabilidade estrutural) de uma cerâmica de zircônia tetragonal policristalina estabilizada por ítria (Y-TZP) desgastada. Discos de cerâmica Y-TZP (VITA In-Ceram YZ) foram confeccionados (ISO:6872-2015; 15mm de diâmetro e 1,2 ± 0,2mm de espessura) e randomicamente divididos em 10 grupos de acordo com dois fatores: "envelhecimento" (com e sem) e "tratamento de superfície" (Ctrl - sem tratamento; Gr - desgaste com ponta diamantada grossa; Gr + HT - desgaste mais tratamento térmico; Gr + Pol - desgaste mais polimento; Gr + Gl - desgaste mais glazeamento). Foram realizadas as análises de rugosidade (n=30), flexão biaxial (n=30), transformação de fase (n=2) e topografia de superfície (n=2). O envelhecimento levou a um aumento intenso no conteúdo de fase monoclínica (m) em todas as condições testadas, sendo observada uma maior susceptibilidade de transformação de fase t-m nas amostras do grupo controle (Ctrl= 65.6%). Apesar de provocar elevada transformação de fase, o envelhecimento não apresentou efeitos negativos nos desfechos avaliados. Não houve redução significativa do módulo de Weibull após os tratamentos. Além disso, o tratamento térmico e o glaze após desgaste levaram a uma redução da resistência característica, enquanto que o grupo polimento apresentou o mais alto valor de resistência característica. O glaze e o tratamento térmico geraram o pior desempenho mecânico, portanto a realização do polimento após desgaste de uma cerâmica Y-TZP é obrigatória.


Subject(s)
Yttrium/chemistry , Zirconium/chemistry , Dental Materials/chemistry , Dental Polishing/methods , Surface Properties , X-Ray Diffraction , Materials Testing , Microscopy, Electron, Scanning , Microscopy, Atomic Force , Flexural Strength , Hot Temperature
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