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This study aims to characterize a new Ti-25Ta-25Nb-5Sn alloy for biomedical application. Microstructure, phase formation, mechanical and corrosion properties, along with the cell culture study of the Ti-25Ta-25Nb alloy with Sn content 5 mass% are presented in this article. The experimental alloy was processed in an arc melting furnace, cold worked, and heat treated. For characterization, optical microscopy, X-ray diffraction, microhardness, and Young's modulus measurements were employed. Corrosion behavior was also evaluated using open-circuit potential (OCP) and potentiodynamic polarization. In vitro studies with human ADSCs were performed to investigate cell viability, adhesion, proliferation, and differentiation. Comparison among the mechanical properties observed in other metal alloy systems, including CP Ti, Ti-25Ta-25Nb, and Ti-25Ta-25-Nb-3Sn showed an increase in microhardness and a decrease in the Young's modulus when compared to CP Ti. The potentiodynamic polarization tests indicated that the corrosion resistance of the Ti-25Ta-25Nb-5Sn alloy was similar to CP Ti and the experiments in vitro demonstrated great interactions between the alloy surface and cells in terms of adhesion, proliferation, and differentiation. Therefore, this alloy presents potential for biomedical applications with properties required for good performance.
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Neoplasms are among the most impacting disease diagnoses in veterinary medicine and have become increasingly common due to the greater longevity of animals as living conditions improved. The Mongolian gerbil is a small rodent species that has become popular recently. In these animals, the occurrence of neoplastic processes is relatively common, mainly tumors of the ventral gland in males and ovarian tumors in females. This work aims to report an ovarian tumor in a Mongolian gerbil Meriones unguiculatus Milne-Edwards 1867 (Rodentia, Muridae). At the initial presentation, the animal had dyspnea, prostration, and increased abdominal volume in the topography of the right ovary of approximately 2 cm. The animal was submitted to exploratory laparotomy because of the emergency nature of the case and the owners' refusal of additional exams due to financial restrictions. Thus, an ovariohysterectomy was performed, followed by a histopathological examination. The histopathology revealed an ovarian papillary carcinoma affecting both ovaries and cystic endometrial hyperplasia. With surgical removal and drainage of the thoracic fluid, the animal showed good recovery, with general improvement and return to regular activity, with a life expectancy of two years. Currently, the demand for specialized veterinarians for unconventional pets is increasing. This condition allows owners to raise their animals more properly, favoring greater longevity. Knowledge about the prevalence and incidence of diseases in different species is of enormous relevance in establishing the appropriate therapy, improving life quality, and increasing life expectancy in animals' lives.(AU)
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Animais , Feminino , Carcinoma Papilar/fisiopatologia , Gerbillinae , Neoplasias/veterinária , Neoplasias Ovarianas/veterináriaRESUMO
The study of new metallic biomaterials for application in bone tissue repair has improved due to the increase in life expectancy and the aging of the world population. Titanium alloys are one of the main groups of biomaterials for these applications, and beta-type titanium alloys are more suitable for long-term bone implants. The objective of this work was to process and characterize a new Ti10Mo8Nb6Zr beta alloy. Alloy processing involves arc melting, heat treatment, and cold forging. The characterization techniques used in this study were X-ray fluorescence spectroscopy, X-ray diffraction, differential scanning calorimetry, optical microscopy, microhardness measurements, and pulse excitation technique. In vitro studies using adipose-derived stem cells (ADSC) were performed to evaluate the cytotoxicity and cell viability after 1, 4, and 7 days. The results showed that the main phase during the processing route was the beta phase. At the end of processing, the alloy showed beta phase, equiaxed grains with an average size of 228.7 µm, and low Young's modulus (83 GPa). In vitro studies revealed non-cytotoxicity and superior cell viability compared to CP Ti. The addition of zirconium led to a decrease in the beta-transus temperature and Young's modulus and improved the biocompatibility of the alloy. Therefore, the Ti10Mo8Nb6Zr alloy is a promising candidate for application in the biomedical field.
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Aim: To established a simple, controlled and reproducible method to synthesize gallium (Ga)-coated polydopamine (PDA) nanoparticles (NPs). Materials & methods: PDA NPs were synthesized in alkali medium with posterior Ga shell formation due to ion chelation on the NP surface. Results: The obtained results with energy-dispersive x-ray spectroscopy confirmed the incorporation of Ga on the PDA NP surface. The cytotoxicity of Ga-coated PDA NPs was evaluated in vitro at different concentrations in contact with human adipose-derived stem cells. Further cell analysis also demonstrated the benefit of Ga-coated PDA NPs, which increased the cell proliferation rate compared with noncoated PDA NPs. Conclusion: This study indicated that Ga could work as an appropriate shell for PDA NPs, inducing cell proliferation at the analyzed concentrations.
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Gálio , Indóis , Nanopartículas , Polímeros , Adipócitos , Humanos , Células-TroncoRESUMO
The polymer poly(ε-caprolactone) (PCL) has been used in the biomaterial field for its relatively inexpensive price and suitability for modification. Also, its chemical and biological properties are desirable for biomedical applications. The electrospinning process has been used for producing polymer fibers of PCL due in large part to an increased interest in nanoscale properties and technologies. Moreover, the use of biocompatible polymers for the viability of cell growth is a promising alternative to improve osseointegration. Characterization techniques such as scanning electron microscopy and contact angle were used for analyses of samples. Adult human dermal fibroblasts (neonatal) were utilized to evaluate the biocompatibility of the association of the electrospinning process of the biocompatible polymer (PCL) with TiO2 nanotubes on the Ti-30Ta alloy surface. The results of this study showed a favorable response for adhesion on the surface. This promising material is due to the modulation of the biological response.
Assuntos
Fibroblastos/efeitos dos fármacos , Nanofibras , Nanotubos , Tantálio , Titânio/farmacologia , Ligas , Materiais Biocompatíveis , Caproatos , Humanos , Lactonas , Teste de Materiais/métodos , Microscopia Eletrônica de Varredura , Polímeros , Pele/citologia , Pele/efeitos dos fármacos , Titânio/químicaRESUMO
This animal study evaluated the osseointegration level of a new nanotextured titanium surface produced by anodization. Ti-cp micro-implants (1.5 mm diameter by 2.5 mm in length) divided into two groups: titanium nanotextured surface treatment (Test Group) and acid etched surface treatment (Control Group). Surface characterization included morphology analysis using scanning electron microscopy and wettability by measuring contact angle. Sixteen Wistar rats were submitted to two micro implants surgical placement procedures. In each rat, one type of micro implant placed in each tibia. The animals sacrificed after two (T1) and six weeks (T2) post-implantation. After the euthanasia, tibias processed for histomorphometric analysis, which allowed the evaluation of bone to implant contact (BIC) and the bone area fraction occupancy between the threads (BAFO). Our surface analysis data showed that the Control Group exhibited an irregular and non-homogenous topography while the Test Group showed a nanotextured surface. The Test Group showed higher wettability (contact angle = 5.1 ± 0.7°) than the Control Group (contact angle = 75.5 ± 4.6°). Concerning the histomorphometric analysis results for T1, Control and Test groups showed BIC percentages of 41.3 ± 15.2% and 63.1 ± 8.7% (p < 0.05), respectively, and for BAFO, 28.7 ± 13.7% and 54.8 ± 7.5%, respectively (p < 0.05). For T2, the histomorphometric analysis for Control and Test groups showed BIC percentages of 51.2 ± 11.4% and 64.8 ± 7.4% (p < 0.05), respectively and for BAFO, 36.4 ± 10.3% and 57.9 ± 9.3% (p < 0.05), respectively. The findings of the current study confirmed that the novel nanotextured surface exhibited superior wettability, improved peri-implant bone formation, and expedited osseointegration.
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Aim: In dental implant treatment, there is a demand for mechanically stronger implants. Despite the existence of several studies showing the clinical success of narrow diameter implants, most of them are based on pure titanium (cpTi) alloys. There is a few clinical evidences of the success rate of titanium-zirconium (TiZr) narrow diameter implants. The aim of this study was to evaluate the stress distribution in the peri-implant area of narrow diameter cpTi and TiZr implants under axial and oblique loads. Methods: Photoelastic models were produced using epoxy resin (PL2, Vishay Precision Group) from a master model. The implants (cpTi and TiZr; Straumann AG) had 3.3 mm in diameter and 12 mm in height. Loads of 100 N and 200 N were applied to the abutment at angles of 0° (axial), 10°, 20°, and 30° (oblique). A circular polariscope (Eikonal) was used under dark field white-light configuration. The isochromatic fringes were analyzed in the peri-implant region in 5 areas, using ASTM table with isochromatic fringes; cervical-mesial, cervical-distal, mid-mesial, mid-distal and apical. Results: In general, under axial and oblique loads, the stress in the TiZr implant was lower than in the cpTi implant. The load of 200 N produced the highest stress values in cpTi and TiZr implants. In both implants and loads, the fringes were located more in apical area at all angles evaluated. Conclusion: It can be concluded that for small implants, the load inclination and intensity change the pattern of stress distribution and the cpTi implant exhibited the highest peri-implant stress
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Estresse Mecânico , Titânio , Implantes Dentários , Análise do Estresse DentárioRESUMO
Introduction: Adults with sequelae of periodontal disease tend to have bone loss, with consequent flaring of the maxillary incisors. Objective: The influence of bone loss and the inclination of the maxillary incisor in the distribution of stresses due to simulated bite forces was studied. Material and method: Models in epoxy resin were made in three conditions (without bone loss and with bone loss of 5mm and 8mm). Increases in the labial inclination of the maxillary incisor of 10° and 20° were obtained with a beveled metallic block. Loads of 100N were applied five times in each condition using a universal test machine. The models were observed and filmed with a circular polariscope. Orders of isochromatic fringes (stresses) on the labial, lingual, and apex surfaces were recorded. The agreement of the data was evaluated using the weighted kappa test, and the results were 0.89 and 0.82 for intra- and inter-examiners, respectively. Result: The results of the Kruskal-Wallis and SNK tests indicated higher stresses (2.0) with increased labial inclination in the labial surface; higher stresses (2.67) with increased bone loss; higher greater stresses with the association of bone loss and labial-inclination (3.6); and the highest stresses tended to concentrate on the labial surfaces, except in cases of normal inclination and without bone loss (0.45). Conclusion: It was concluded that increases in both the labial inclination of the maxillary incisors and bone loss increase periradicular stresses, and the combination of these factors further increases the stresses due to bite forces, with the highest concentration on the labial side.
Introdução: Adultos com sequelas de doenças periodontais tendem a apresentar perda óssea, com consequente vestibularização dos incisivos superiores. Objetivo: A influência da perda óssea e da inclinação do incisivo superior na distribuição de tensões devido a forças mastigatórias simuladas foram avaliadas nesse estudo. Material e método: Modelos em resina epóxi foram confeccionados em três condições (sem perda óssea e com perda óssea de 5mm e 8mm). Aumentos na inclinação vestibular do incisivo superior de 10° e 20° foram obtidos com um bloco metálico chanfrado. Cargas de 100N foram aplicadas cinco vezes em cada condição usando uma máquina de ensaio universal. Os modelos foram observados e filmados com um polariscópio circular. Ordens de franjas isocromáticas (tensões) nas faces vestibular, lingual e apical foram registradas. A concordância dos dados foi avaliada pelo teste kappa ponderado e os resultados foram 0,89 e 0,82 para intra e interexaminadores, respectivamente. Resultado: Os resultados dos testes de Kruskal-Wallis e SNK indicaram maiores tensões (2,0) com aumento da inclinação vestibular na face vestibular; maiores tensões (2,67) com aumento da perda óssea; maior tensão com a associação de perda óssea e inclinação vestibular (3,6); e as maiores tensões tenderam a concentrar-se na face vestibular, exceto em casos de inclinação normal e sem perda óssea (0,45). Conclusão: Concluiu-se que aumentos tanto da inclinação vestibular dos incisivos superiores quanto da perda óssea aumentam as tensões perirradiculares, e a combinação desses fatores aumenta ainda mais as tensões devido às forças mastigatórias, com a maior concentração na face vestibular.
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Doenças Periodontais , Força de Mordida , Perda do Osso Alveolar , Estatísticas não Paramétricas , Análise do Estresse Dentário , Incisivo , Reabsorção Óssea , Resinas EpóxiRESUMO
In this study, ordered and uniform TiO2 nanotubular structures were obtained on the surface of the Ti15Mo alloy by anodic oxidation. The amorphous state of TiO2 nanotubes formed under different anodization conditions was investigated. Crystallization of TiO2 into anatase phase occurs during annealing at temperatures of around 400°C, whereas anatase to rutile transformation starts around 500°C and is completed at 800°C. Phase transformations in annealed samples led to morphological changes of tubular nanostructures, suggesting that the oxide layer formed at the nanotube/substrate interface serves as nucleation sites for more stable phases of TiO2. The proliferation of fibroblasts cells under annealing conditions of 450°C, and of untreated samples (control group), was evaluated after 1, 4, and 7 days in cell culture using fluorescence microscopy images. A gradual increase in the number and size of cells was observed, indicating a non-toxic alloy. There was also better surface coverage on anodized samples compared with the untreated group; as well as increased development of the cytoskeleton in samples after anodization. The results of this study showed that the growth of TiO2 nanotubular structures associated with annealing allow better cell adhesion on the Ti15Mo alloy surface.
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Ligas/química , Molibdênio/química , Nanotubos/química , Titânio/química , Adesão Celular , Linhagem Celular , Cristalização , Eletrodos , Fibroblastos/citologia , Humanos , Oxirredução , Tamanho da Partícula , Propriedades de SuperfícieRESUMO
INTRODUCTION:: Plasma-polymerized film deposition was created to modify metallic orthodontic brackets surface properties in order to inhibit bacterial adhesion. METHODS:: Hexamethyldisiloxane (HMDSO) polymer films were deposited on conventional (n = 10) and self-ligating (n = 10) stainless steel orthodontic brackets using the Plasma-Enhanced Chemical Vapor Deposition (PECVD) radio frequency technique. The samples were divided into two groups according to the kind of bracket and two subgroups after surface treatment. Scanning Electron Microscopy (SEM) analysis was performed to assess the presence of bacterial adhesion over samples surfaces (slot and wings region) and film layer integrity. Surface roughness was assessed by Confocal Interferometry (CI) and surface wettability, by goniometry. For bacterial adhesion analysis, samples were exposed for 72 hours to a Streptococcus mutans solution for biofilm formation. The values obtained for surface roughness were analyzed using the Mann-Whitney test while biofilm adhesion were assessed by Kruskal-Wallis and SNK test. RESULTS:: Significant statistical differences (p< 0.05) for surface roughness and bacterial adhesion reduction were observed on conventional brackets after surface treatment and between conventional and self-ligating brackets; no significant statistical differences were observed between self-ligating groups (p> 0.05). CONCLUSION:: Plasma-polymerized film deposition was only effective on reducing surface roughness and bacterial adhesion in conventional brackets. It was also noted that conventional brackets showed lower biofilm adhesion than self-ligating brackets despite the absence of film.
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Aderência Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Braquetes Ortodônticos/microbiologia , Siloxanas/farmacologia , Streptococcus mutans/efeitos dos fármacos , Streptococcus mutans/fisiologia , Desenho de Aparelho Ortodôntico , Plasma , Polimerização , Streptococcus mutans/isolamento & purificação , Propriedades de SuperfícieRESUMO
ABSTRACT Introduction: Plasma-polymerized film deposition was created to modify metallic orthodontic brackets surface properties in order to inhibit bacterial adhesion. Methods: Hexamethyldisiloxane (HMDSO) polymer films were deposited on conventional (n = 10) and self-ligating (n = 10) stainless steel orthodontic brackets using the Plasma-Enhanced Chemical Vapor Deposition (PECVD) radio frequency technique. The samples were divided into two groups according to the kind of bracket and two subgroups after surface treatment. Scanning Electron Microscopy (SEM) analysis was performed to assess the presence of bacterial adhesion over samples surfaces (slot and wings region) and film layer integrity. Surface roughness was assessed by Confocal Interferometry (CI) and surface wettability, by goniometry. For bacterial adhesion analysis, samples were exposed for 72 hours to a Streptococcus mutans solution for biofilm formation. The values obtained for surface roughness were analyzed using the Mann-Whitney test while biofilm adhesion were assessed by Kruskal-Wallis and SNK test. Results: Significant statistical differences (p< 0.05) for surface roughness and bacterial adhesion reduction were observed on conventional brackets after surface treatment and between conventional and self-ligating brackets; no significant statistical differences were observed between self-ligating groups (p> 0.05). Conclusion: Plasma-polymerized film deposition was only effective on reducing surface roughness and bacterial adhesion in conventional brackets. It was also noted that conventional brackets showed lower biofilm adhesion than self-ligating brackets despite the absence of film.
RESUMO Introdução: a deposição de filme de polímero a plasma foi criada para modificar as propriedades de superfície dos braquetes ortodônticos metálicos, com o intuito de inibir a adesão bacteriana. Métodos: filmes finos de polímero de hexametildisiloxano (HMDSO) foram depositados em braquetes ortodônticos de aço inoxidável convencionais (n = 10) e autoligáveis (n = 10), utilizando a técnica de radiofrequência PECVD (Plasma-Enhanced Chemical Vapor Deposition). As amostras foram divididas em dois grupos, de acordo com o tipo de braquete, e dois subgrupos após o tratamento de superfície. A microscopia eletrônica de varredura (MEV) foi realizada para avaliar a presença de adesão bacteriana sobre as superfícies das amostras (região de ranhura horizontal e aletas) e a integridade da camada de filme. A Interferometria Confocal (CI) avaliou a rugosidade, e a molhabilidade superficial foi avaliada por goniometria. Para análise de adesão bacteriana, as amostras foram expostas durante 72 horas a uma solução de Streptococcus mutans, para formação de biofilme. Os valores obtidos para a rugosidade da superfície foram analisados pelo teste de Mann-Whitney, enquanto a adesão do biofilme foi avaliada pelos testes de Kruskal-Wallis e SNK. Resultados: observaram-se diferenças estatisticamente significativas (p <0,05) para a rugosidade superficial e redução da adesão bacteriana em braquetes convencionais após o tratamento da superfície, e entre braquetes convencionais e autoligáveis. Não foram observadas diferenças estatísticas significativas entre os grupos autoligáveis (p> 0,05). Conclusão: a deposição de polímero a plasma só foi efetiva na redução da rugosidade superficial e adesão bacteriana em braquetes convencionais. Observou-se, também, que os braquetes convencionais apresentaram menor adesão ao biofilme do que os braquetes autoligáveis, apesar da ausência de filme.
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Siloxanas/farmacologia , Streptococcus mutans/efeitos dos fármacos , Streptococcus mutans/fisiologia , Aderência Bacteriana/efeitos dos fármacos , Braquetes Ortodônticos/microbiologia , Biofilmes/efeitos dos fármacos , Plasma , Streptococcus mutans/isolamento & purificação , Propriedades de Superfície , Desenho de Aparelho Ortodôntico , PolimerizaçãoRESUMO
Archaeological research has identified the use of cultivated cotton (Gossypium barbadense) in the ancient Andes dating back to at least 7800 years ago. Because of unusual circumstances of preservation, 6000-year-old cotton fabrics from the Preceramic site of Huaca Prieta on the north coast of Peru retained traces of a blue pigment that was analyzed and positively identified as an indigoid dye (indigotin), making it the earliest known use of indigo in the world, derived most likely from Indigofera spp. native to South America. This predates by ~1500 years the earliest reported use of indigo in the Old World, from Fifth Dynasty Egypt [ca. 4400 BP (before present)]. Indigo is one of the most valued and most globally widespread dyes of antiquity and of the present era (it being the blue of blue jeans).
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Corantes/história , Gossypium/química , Índigo Carmim/história , Arqueologia/história , Corantes/química , Gossypium/crescimento & desenvolvimento , Hispânico ou Latino , História Antiga , Humanos , Índigo Carmim/química , Peru , Têxteis/históriaRESUMO
The aim of this study was to analyze, through Vickers hardness test and photoelasticity analysis, pre-bent areas, manually bent areas, and areas without bends of 10-mm advancement pre-bent titanium plates (Leibinger system). The work was divided into three groups: group I-region without bend, group II-region of 90° manual bend, and group III-region of 90° pre-fabricated bends. All the materials were evaluated through hardness analysis by the Vickers hardness test, stress analysis by residual images obtained in a polariscope, and photoelastic analysis by reflection during the manual bending. The data obtained from the hardness tests were statistically analyzed using ANOVA and Tukey's tests at a significance level of 5 %. The pre-bent plate (group III) showed hardness means statistically significantly higher (P < 0.05) than those of the other groups (I-region without bends, II-90° manually bent region). Through the study of photoelastic reflection, it was possible to identify that the stress gradually increased, reaching a pink color (1.81 δ / λ), as the bending was performed. A general analysis of the results showed that the bent plate region of pre-bent titanium presented the best results.
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Placas Ósseas , Teste de Materiais , Maxila/cirurgia , Estresse Mecânico , Elasticidade , Dureza , Osteotomia Maxilar/efeitos adversos , TitânioRESUMO
In this study, in vitro cytocompatibility was investigated in the Ti-30Ta alloy after two kinds of surfaces treatments: alkaline and biomimetic treatment. Each condition was evaluated by scanning electron microscopy/energy-dispersive X-ray spectroscopy. Cellular adhesion, viability, protein expression, morphology, and differentiation were evaluated with Bone marrow stromal cells (MSCs) to investigate the short and long-term cellular response by fluorescence microscope imaging and colorimetric assays techniques. Two treatments exhibited similar results with respect to total protein content and enzyme activity as compared with alloy without treatment. However, it was observed improved of the biomineralization, bone matrix formation, enzyme activity, and MSCs functionality after biomimetic treatment. These results indicate that the biomimetic surface treatment has a high potential for enhanced osseointegration.
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Ligas , Células-Tronco Mesenquimais/citologia , Tantálio , Titânio , Animais , Microscopia Eletrônica de Varredura , Ratos , Ratos Wistar , Propriedades de SuperfícieRESUMO
OBJECTIVE: The purpose of the present study was to evaluate the influence of radiation in osseointegrated dental implants installed in tibiae of rats. MATERIAL AND METHODS: Screw-shaped implants (2.5 mm diameter by 3.5 mm length) were custom made from commercially pure titanium bars. Titanium implants were blasted and sterilized before implantation. Animals were divided into two groups of 12 animals each and the rats were not paired after the groups' formation. The experimental group (group 1) received external irradiation 4 weeks after surgery while in the control group (group 2) animals were kept free of radiation. The shear strength required to detach the implant from bone was measured by push-out testing and osseointegration was histologically evaluated. RESULTS: Results showed that the compressive strength of irradiated implants (33.49 MPa) was significantly lower than the compressive strength of non-irradiated implants (48.05 MPa). CONCLUSIONS: We concluded that the mechanical strength bonding between implants and host tissues decreased after irradiation.
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Implantação Dentária Endóssea , Implantes Dentários , Osseointegração/efeitos da radiação , Tíbia/efeitos da radiação , Tíbia/cirurgia , Animais , Fenômenos Biomecânicos , Parafusos Ósseos , Planejamento de Prótese Dentária , Implantes Experimentais , Masculino , Distribuição Aleatória , Ratos , Ratos Wistar , Estatísticas não Paramétricas , Propriedades de Superfície , TitânioRESUMO
Diversos tratamentos da superfície dos implantes dentários têm sido desenvolvidos com o objetivo de garantir ancoragem ao tecido ósseo, otimização dos determinantes de estrutura eletrônica, cristalinidade, composição e propriedades. As técnicas de recobrimento têm sido propostas com o objetivo de criar união bioquímica capaz de acelerar as fases iniciais de formação do tecido ósseo, aliando as propriedades positivas do titânio e suas ligas à bioatividade dos materiais cerâmicos. Este trabalho aborda protocolo de manipulação do SBF para recobrimento de ligas de titânio. A obtenção do recobrimento com nucleação de apatita ocorre por imersão do substrato em solução sintética que simula o plasma sanguíneo (Simulated Body Fluid). O protocolo de manipulação da solução SBF permite estabelecer diretrizes racionalizadas quanto ao uso e organizadas de modo a tornar prática sua aplicação
Various surface treatments of dental implants have been developed in order to ensure anchorage to bone tissue, optimization of the determinants of electronic structure, crystallinity, composition and properties. Coating techniques have been proposed in order to create union biochemical able to accelerate the early stages of bone tissue, combining the positive properties of titanium and its alloys bioactivity of ceramic materials. This paper discusses protocol for handling the SBF coating of titanium alloys. The apatite phase nucleation occurs by immersing the substrate in synthetic solution simulating blood plasma (Simulated Body Fluid). The protocol allows manipulation of the SBF solution to establish guidelines regarding the use streamlined and organized to make practical application
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Durapatita , Implantes Dentários , Propriedades de SuperfícieRESUMO
The present study evaluated microstructure, microhardness and wear resistance of experimental titanium alloys containing zirconium and tantalum. Alloys were melted in arc melting furnace according to the following compositions: Ti-5Zr, Ti-5Ta and Ti-5Ta-5Zr (%wt). Hemispheres and disks were obtained from wax patterns that were invested and cast by plasma. Microstructures were evaluated using optical microscopy and X-ray diffraction (XRD) analysis and also Vickers microhardness was measured. Hemispherical samples and disks were used for 2-body wear tests, performed by repeated grinding of the samples. Wear resistance was assessed as height loss after 40,000 cycles. The data were compared using ANOVA and post-hoc Tukey test. Ti-5Zr presented a Widmanstätten structure and the identified phases were α and α' while Ti-5Ta and Ti-5Ta-5Zr presented α, ß, α' and α" phases, but the former presented a lamellar structure, and the other, acicular. The microhardness of Ti-5Zr was significantly greater than other materials and cp Ti presented wear resistance significantly lower than experimental alloys. It was concluded that wear resistance was improved when adding Ta and Zr to titanium and Zr increased microhardness of Ti-5Zr alloy.
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Ligas/química , Materiais Dentários/química , Fenômenos Mecânicos , Titânio/química , Dureza , Tantálio/química , Zircônio/químicaRESUMO
Várias ligas têm sido utilizadas na confecção de restaurações protéticas nos últimos anos. Essas ligas apresentam na sua composição ouro, paládio, prata, níquel, cobalto, cromo e titânio; quando na cavidade bucal são passíveis de corrosão, a qual pode empobrecer a estética e comprometer as propriedades físicas e biológicas. O objetivo deste trabalho foi avaliar a resistência a corrosão de duas ligas odontológicas, Ni-Cr e Ni-Cr-Ti em três tipos de colutórios bucais com diferentes ingredientes ativos: colutório I 0.5g/l de cloreto de cetilpiridíneo +0.05 de fluoreto de sódio; colutório II -0.05 de fluoreto de sódio + 0.03% de triclosan e colutório III 0.12% de diclonato de clorexidina. Curvas potenciodinâmicas foram realizadas por meio de potenciostato PAR283 e célula de vidro convencional de parede dupla para termostatização. Utilizou-se eletrodo de referência Ag/ AgCl, KClsat e auxiliar espiral de platina. A microestrutura das duas ligas foi observada por meio de microscopia ótica. Análise das curvas obtidas mostraram que a liga Ni-Cr foi menos reativa na presença de digluconato de clorexida a 0.12%, enquanto a liga Ni-Cr-Ti foi mais sensível para os outros dois tipos de colutório. Isto ocorreu, provavelmente, devido a presença de titânio na composição desta liga. Análise microestrutural revelou microsestrutura dendrítica na liga Ni-Cr e eutéticos na liga Ni-Cr-Ti
Several alloys have been used for prosthodontics restorations in the last years. These alloys have a number of metals that include gold, palladium, silver, nickel, cobalt, chromium and titanium and they are used in oral cavity undergo several corrosion. Corrosion can lead to poor esthetics, compromise of physical properties, or increased biological irritation. The objective of this study was evaluated corrosion resistance of two alloys Ni-Cr and Ni-Cr-Ti in three types of mouthwashes with different active ingredients: 0.5g/l cetylpyridinium chloride + 0.05% sodium fluoride, 0.05% sodium fluoride + 0.03% triclosan (with fluor) and 0.12% chlorohexidine digluconate. The potentiodynamic curves were performed by means of an EG&G PAR 283 potentiostat/galvanostat. The counter electrode was a platinum wire and reference electrode was an Ag/AgCl, KCl saturated. Before each experiment, working electrodes were mechanically polished with 600 and 1200 grade papers, rinsed with distilled water and dried in air. All experiments were carried out at 37.0oC in conventional three-compartment double wall glass cell containing mouthwashes. The microstructures of two alloys were observed in optical microscopy. Analysis of curves showed that Ni-Cr alloy was less reactive in the presence of 0.12% chlorohexidine digluconate while Ni-Cr-Ti alloy was more sensitive for others two types of mouthwashes (0.5g/l cetylpyridinium chloride + 0.05% sodium fluoride® and 0.05% sodium fluoride + 0.03% triclosan). This occurred probably due presence of titanium in this alloy. Microstructural analysis reveals the presence of dendritic and eutectic microstructures for NiCr and Ni-Cr-Ti, respectively
Assuntos
Antissépticos Bucais , Corrosão , TitânioRESUMO
The most commonly used titanium (Ti)-based alloy for biological applications is Ti-6Al-4V, but some studies associate the vanadium (V) with the cytotoxic effects and adverse reactions in tissues, while aluminum (Al) has been associated with neurological disorders. Ti-Nb alloys belong to a new class of Ti-based alloys with no presence of Al and V and with elasticity modulus values that are very attractive for use as a biomaterial. It is well known that the presence of interstitial elements (such as oxygen, for example) changes the mechanical properties of alloys significantly, particularly the elastic properties, the same way that heat treatments can change the microstructure of these alloys. This article presents the effect of heat treatment and oxygen doping in some mechanical properties and the biocompatibility of three alloys of the Ti-Nb system, characterized by density measurements, X-ray diffraction, optical microscopy, Vickers microhardness, in vitro cytotoxicity, and mechanical spectroscopy.
Assuntos
Ligas/química , Materiais Biocompatíveis , Temperatura Alta , Nióbio/química , Oxigênio/química , Titânio/química , Células 3T3 , Ligas/toxicidade , Animais , Adesão Celular , Proliferação de Células , Forma Celular , Sobrevivência Celular/efeitos dos fármacos , Módulo de Elasticidade , Dureza , Testes de Dureza , Teste de Materiais , Camundongos , Nióbio/toxicidade , Osteoblastos/fisiologia , Desenho de Prótese , Análise Espectral , Propriedades de Superfície , Titânio/toxicidade , Difração de Raios XRESUMO
Riscos de injúrias mecânicas contra indicam a escovação e elegem os agentes químicos como meios adequados para higienização diária de próteses removíveis reembasadas com materiais resilientes. Foi avaliado o efeito de agentes químicos de limpeza sobre a capacidade de umedecimento de uma marca comercial de reembasador resiliente acrílico (Dentusoft®) por uma marca comercial de gesso pedra tipo IV (Durone IV®). Utilizou-se 20 discos de resina acrílica termoativada (VipiCril®) com 30mm de diâmetro e 4mm de espessura, recobertos por 2mm de reembasador. Divididos em 4 grupos foram estocados em saliva artificial a 37+1ºC por 30dias, imersos diariamente por 15minutos em água destilada(GI), pastilhas efervescentes (Corega®Tabs) à base de peróxido (GII), solução de bicarbonato de sódio(GIII) ou solução de hipoclorito de sódio (GIV), após os quais, sobre o reembasador foram vertidos 2ml de gesso tipo IV (Durone IV®). Atingida a presa final do gesso os espécimes foram seccionados vertical e medianamente, regularizados com lixa de água nº400 e montados em dispositivo adequado para leitura (nos lados direito e esquerdo) do ângulo de contato em microscópio Carl Zeiss (precisão 0,001). Os resultados obtidos, submetidos à análise, mostraram distribuição não-normal, optando-se por teste não-paramétrico. Realizado teste de Kruskal Wallis a 5% de significância, verificou-se diferença estatística entre os grupos, com média menor do ângulo de contato para GII. Concluiu-se que o agente químico de limpeza Corega®Tabs permitiu a melhor adaptação do material reembasador pelo gesso estudado
Risk of mechanical injuries contraindicate brushing and elect chemical agents as appropriate for daily cleaning of dentures relined with resilient materials. It was evaluated the effect of denture cleansers on the wettability of denture relining material (Dentusoft, Dental Medrano). We used 20 discs of acrylic resin thermoactivated VipiCril® with 30mm diameter and 4mm thick, covered by 2mm Dentusoft®. Divided into 4grupos were stored in artificial saliva at 37 +1 ºC for 30 days, immersed daily for 15minutes in distilled water (GI), Corega®Tabs (GII), a solution of sodium bicarbonate (GIII) or solution of sodium hypochlorite (GIV) after which, on the soft liner were poured 2 ml of type IV gypsum (Durone IV, Dentsply). Reached the final setting of the gypsum specimens were sectioned vertically and medially, settled water with sandpaper No. 400 and mounted on suitable device for reading (in the right and left) of the contact angle Carl Zeiss microscope (precision, 001). The results were submitted to analysis, showed non-normal distribution, opting for non-parametric test. Kruskal Wallis test performed at 5% significance, there was statistical difference between the groups with lower average contact angle for GII. It was concluded that the chemical cleaning Corega Tabs® allowed a better adaptation of relining the gypsum studied