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Resumen: Existe en el mercado una gran cantidad de alambres de aleaciones de níquel-titanio; sin embargo, no todos poseen las características ideales de memoria de forma y superelasticidad para ser utilizados en ortodoncia. El objetivo de este estudio fue encontrar la temperatura austenitica final de estos arcos con la finalidad de determinar la fase de transformación para su mejor uso clínico en Ortodoncia. Métodos: Se estudiaron once alambres de níquel-titanio más utilizados en Ortodoncia y se evaluó la fase de transformación utilizando la prueba de calorimetría de barrido diferencial. Conclusiones: Este estudio muestra cómo algunos arcos de NiTi en Ortodoncia presentan resultados contrarios a los que promocionan.
Abstract: There are many nickel-titanium alloy wires available in the market. Nevertheless not all of them possess the ideal characteristics of shape memory and super-elasticity to be used in orthodontic treatment. The aim of the present study was to find austenitic final temperature of these archwires so as to determine the transformation phase in order to better use them in orthodontics. Methods: Eleven nickel-titanium orthodontic wires were selected. Transformation phase was assessed using differential scanning calorimetry method. Conclusions: The present study illustrates how some orthodontic Ni-Ti wires elicit results contrary to those advertised.
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Titanium and its alloys are being extensively researched and are applied relatively in different fields of dentistry since 1970s. Every property of this metal has proven to be useful in allied branches of dentistry like casting of removable partial denture frameworks, endosseous implants, in surgical reconstruction and orthodontics. Its inherent advantages like high strength, ductility, formability and weldability, low modulus of elasticity, ease of formation of oxidized surface layer, ability to retain mechanical integrity after autoclave and relatively low toxicity has led to extensive application of titanium and its alloys. The success of the treatment modality relies anyways on the knowledge of the properties required to employ them at the right situation. This article provides an insight into the properties of titanium and its alloys employed as a biomaterial for variety of purposes in dentistry with its definitive pros and cons.
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Objective To improve the long-term biocompatibility and mechanical stability of Titanium alloy implants. Method micro-nano patterned TiO2 thin films have been prepared on TC4 substrates via a sol-gel dip-coating method with Ti(OC4H9)4 (TEOT) as precursor and polyethylene glycol (PEG) as organic template. The influence of PEG concentration upon the morphology of the target films has been studied by using AFM. The wettability and tribological properties of the target films have been studied by means of optical contact angle measuring instrument and UMT-2. Results When increasing the PEG concentration to 3.5g/100mL, a parallel arranged groove structure can be obtained on the surface of the sample; compare with TiO2 sol-gel film without adding organic template, the wear resistance of the patterned film is better. Conclusions The feature of the patterned TiO2 films can be controlled by adding different amount of organic template; and it has been proved that a certain kind of patterned structure can improve the wear resistance of the film.
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Objective To improve the long-term biocompatibility and mechanical stability of Titanium alloy implants.Method Micro-nano patterned TiO_2 thin films have been prepared on TC4 substrates via a sol-gel dipcoating method with Ti(OC_4H_9)_4(TEOT)as precursor and polyethylene glycol(PEG)as organic template.The Influence of PEG concentration upon the morphology of the target films has been studied by using AFM.The wettability and tribological properties of the target films have been studied by means of optical contact angle measuring instrument and UMT-2.Results When increasing the PEG concentration to 3.5 g/100 mL,a parallel arranged groove structure can be obtained on the surface of the sample;compared with TiO_2 sol-gel film without adding organic template,the wear resistance of the patterned film is better.Conclusions The feature of the patterned TiO_2 films can be controlled by adding different amount of Organic template;and it has been proved that a certain kind of patterned structure can imeprove the wear resistance of the film.
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Objective To improve the long-term biocompatibility and mechanical stability of Titanium alloy implants.Method Micro-nano patterned TiO_2 thin films have been prepared on TC4 substrates via a sol-gel dipcoating method with Ti(OC_4H_9)_4(TEOT)as precursor and polyethylene glycol(PEG)as organic template.The Influence of PEG concentration upon the morphology of the target films has been studied by using AFM.The wettability and tribological properties of the target films have been studied by means of optical contact angle measuring instrument and UMT-2.Results When increasing the PEG concentration to 3.5 g/100 mL,a parallel arranged groove structure can be obtained on the surface of the sample;compared with TiO_2 sol-gel film without adding organic template,the wear resistance of the patterned film is better.Conclusions The feature of the patterned TiO_2 films can be controlled by adding different amount of Organic template;and it has been proved that a certain kind of patterned structure can imeprove the wear resistance of the film.
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Objective To improve the long-term biocompatibility and mechanical stability of Titanium alloy implants.Method Micro-nano patterned TiO_2 thin films have been prepared on TC4 substrates via a sol-gel dipcoating method with Ti(OC_4H_9)_4(TEOT)as precursor and polyethylene glycol(PEG)as organic template.The Influence of PEG concentration upon the morphology of the target films has been studied by using AFM.The wettability and tribological properties of the target films have been studied by means of optical contact angle measuring instrument and UMT-2.Results When increasing the PEG concentration to 3.5 g/100 mL,a parallel arranged groove structure can be obtained on the surface of the sample;compared with TiO_2 sol-gel film without adding organic template,the wear resistance of the patterned film is better.Conclusions The feature of the patterned TiO_2 films can be controlled by adding different amount of Organic template;and it has been proved that a certain kind of patterned structure can imeprove the wear resistance of the film.
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Introdução: A capacidade de aderência de Candida albicans é um dos seus principais fatores de virulência. Superfícies de materiais diferentes podem propiciar condições para maior ou menor aderência e maior virulência dos microrganismos. Objetivo: Avaliar a aderência de Candida albicans em ligas de titânio e cobalto-cromo, com diferentes desgastes. Material e métodos: Foram confeccionados 24 corpos-deprova (CPs) cilíndricos, 12 de titânio e 12 de cobalto-cromo, divididos em 4 grupos de seis. Todos foram polidos de forma habitual pelo mesmo técnico. Os CPs foram lixados em torno de alta rotação por 15 segundos cada lixa, por toda a sua superfície. Um grupo de cada metal foi lixado apenas com lixa para metal número 80. Os dois outros grupos foram lixados conforme a seqüência (granulação decrescente): 80, 150 e 220. Os CPs foram esterilizados e posicionados em placas de cultura de células. Em cada poço da placa foi adicionada quantidade padronizada de caldo Sabouraud e suspensão contendo 106 céls./mL de C. albicans (ATCC 18804). Após incubação, o número de células aderidas por mm2 foi obtido pelo método de semeadura em placa de Petri. Os valores encontrados foram tabulados e submetidos aos testes de ANOVA e Tukey, com nível de significância de 5%. Resultados: Houve diferença estatística para a granulação de lixas, e não houve diferença quando foram comparados os metais. Conclusão: Quanto maior ?? a granulação final da lixa maior é a aderência, e o tipo de metal não influenciou no resultado.
Introduction: The capacity of Candida albicans adherence is one of its main factors of virulence. Surfaces of different materials can propitiate conditions for higher or lower adherence and greater virulence of the microorganisms. Objective: Evaluate the adherence of Candida albicans in cobalto-chromium and titanium alloys, with different sandpapering. Material and methods: Twenty-four cylindrical samples have been constructed, 12 of titanium and 12 of cobalt-chromium, divided in 4 groups of six. All have been polished in the habitual form by the same technician. Samples have been sandpapered at about high rotation for 15 seconds each sandpaper, on all its surface. A group of each metal was sandpapered only with sandpaper for metal number 80. The two other groups have been sandpapered in agreement with the sequence (decreasing granulation): 80, 150 and 220. Samples have been sterilized and located in plates of cells culture. In each well of the plate was added standardized amount of Sabouraud broth and suspension containing 106 cells per milliliter of C. albicans (ATCC 18804). After incubation, the number of adhered cells per mm2 was obtained by the method of sowing in plate of Petri. The obtained values have been tabulated and submitted to the tests of ANOVA and Tukey, with level of significance of 5%. Results: There was statistical difference for the granulation of sandpapers, what not occurred when considering metals. Conclusion: The bigger the final granulation of sandpaper, the greater the adherence and the type of metal did not influence in the result.