ABSTRACT
Copper NiTi wires were This latest innovation in the evolutionary scale gives us the opportunity of choosing the force level by choosing the temperature at which the wires will deliver its optimum force level. With so many advantages and their ability to return to their original form coupled with the high cost of copper NiTi many clinicians started reusing the wire. This raises concern about disinfecting/sterilizing the wire before using in another patient for prevention of cross infection. Hence, various sterilization procedures like cold sterilization using 2% acidic Glutaraldehyde, dry heat sterilization and autoclaving were used to prevent this cross infection . Aim: The main aim of this study is used to evaluate the effects of different kinds of sterilization on Modulus of elasticity and surface topography of the 0.016 copper NiTi wires before and after sterilization procedure Materials and Methods: In the present study, Three point bending test along with tensile test was performed to evaluate the modulus of elasticity. Scanning electron microscope pictures were used to evaluate surface topography changes. Results: Pretreatment and post treatment values were statistically analyzed by one way ANOVA test. No detrimental changes were detected in tensile properties of copper NiTi were after single cycle of sterilization with any of the stated sterilants. Very minimal non significant changes occurred during the second cycle of sterilization procedure. There was no changes in surface topography of the wire either with dry heat or autoclaving. However, on second treatment cycle with 2% glutaraldehyde, some amount of surface pitting was seen. Conclusion: Dry heat sterilization and autoclaving have been found to have very minimal changes on the tensile properties of these wires after one or two cycles of sterilization procedures, but not statistically significant. No detrimental effect was found on surface topography with dry heat or autoclaving. Results support the use of these sterilization procedures as part of infection control process, if the clinician select to reuse these wires for one time only. However, of late, since there is easy availability and modest cost of these wires it is recommended to use new wires which are supplied sealed sterilized packs for each patient to comply with present admissible standard of hygiene and sterilization.
ABSTRACT
PROPOSIÇÃO: O objetivo desta pesquisa foi apresentar a magnitude e a constância das forças liberadas por fios ortodônticos de níquel-titânio, usados para a correção dos apinhamentos dentários. Outro objetivo foi comparar os dois meios mais utilizados de avaliação da deflexão elástica destes fios: o teste de 3 pontos e o dispositivo de simulação clínica. MATERIAL E MÉTODOS: Foram avaliados 11 grupos de fios de liga predominantemente de níquel-titânio, calibre 0,014, de 6 marcas diferentes (Abzil convencional e termoativado; GAC convencional e termoativado; Morelli convencional e termoativado; Ormco CuNiTi; Orthometric convencional e termoativado e Orthosource convencional e termoativado), em teste de deflexão elástica, nas deflexões de 0,5; 1; 2 e 3mm. Uma máquina de ensaio universal INSTRON 3342, com célula de carga de 10N foi utilizada e, como protocolo, foi seguida a norma ISO 15.841. Para a análise estatística dos resultados foram utilizados os testes: Kolmogorov-Smirnov, para conferir se havia normalidade; teste t independente, para comparação dos resultados do teste de 3 pontos e dos resultados do dispositivo; e o teste ANOVA seguido do teste de Tukey, para comparações entre grupos. RESULTADOS: Houve diferença estatística entre os resultados gerados pelo teste de 3 pontos e os gerados pelo dispositivo. Por ser o teste indicado pela norma ISO citada, somente os resultados do teste de 3 pontos foram considerados. Todos os fios estudados apresentaram pseudoelasticidade em uma faixa de variação de força de até 40cN. Os grupos Abzil convencional, GAC convencional, Morelli termoativado, Ormco CuNiTi e Orthometric convencional apresentaram força dentro de uma faixa considerada ótima para a indução da movimentação dentária (50cN-100cN). Os fios termoativados liberaram forças mais leves que seus pares convencionais. CONCLUSÕES: Dentre os grupos estudados, aqueles que apresentaram pseudoelasticidade...
OBJECTIVE: The purpose of this study was to present the magnitude and the constancy of the forces released by nickel-titanium orthodontic wires, used to treat dental crowding. Another purpose was to compare the most usual types of bending tests used to evaluate these wires: 3-point test and clinical simulation device. MATERIAL AND METHODS: Eleven groups of orthodontic nickel-titanium wires, caliber 0.014, of 6 different brands (Abzil conventional and heat-activated; GAC conventional and heat-activated; Morelli conventional and heat-activated; Ormco CuNiTi; Orthometric conventional and heat-activated and Orthosource conventional and heat-activated) were tested by bending test, at deflections of 0.5; 1; 2 and 3mm. A universal testing machine INSTRON 3342 with a 10N load cell was used and, in order to standardize the tests, the ISO 15.841 regulation was followed. Statistical analysis was performed using the subsequent tests: Kolmogorov-Smirnov to verify normality; independent t test to compare the results of the 3-point test and the results derived from the device, and ANOVA followed by the Tukey test for intergroup comparisons. RESULTS: There were significant differences between the results of the 3-point test and the device. As indicated by the ISO regulation, only the results from the 3-point bending test were considered. All groups were classified as pseudoelastic, within a load range of 40cN, at maximum. The groups Abzil conventional, GAC conventional, Morelli heat-activated, Ormco CuNiTi and Orthometric conventional released load within optimum range (50cN-100cN). Heatactivated wires released lower load compared to conventional wire of the same brand. CONCLUSIONS: Among the groups evaluated those that presented pseudoelasticity, load within a range considered optimal, in a homogeneous manner, were Morelli heat-activated and Ormco CuNiTi.
Subject(s)
Humans , Nickel/chemistry , Orthodontic Wires , Titanium/chemistry , Elastic Modulus , Materials Testing , Malocclusion/therapy , Statistics, NonparametricABSTRACT
PROPOSIÇÃO: O objetivo desta pesquisa foi apresentar a magnitude e a constância das forças liberadas por fios ortodônticos de níquel-titânio, usados para a correção dos apinhamentos dentários. Outro objetivo foi comparar os dois meios mais utilizados de avaliação da deflexão elástica destes fios: o teste de 3 pontos e o dispositivo de simulação clínica. MATERIAL E MÉTODOS: Foram avaliados 11 grupos de fios de liga predominantemente de níquel-titânio, calibre 0,014, de 6 marcas diferentes (Abzil convencional e termoativado; GAC convencional e termoativado; Morelli convencional e termoativado; Ormco CuNiTi; Orthometric convencional e termoativado e Orthosource convencional e termoativado), em teste de deflexão elástica, nas deflexões de 0,5; 1; 2 e 3mm. Uma máquina de ensaio universal INSTRON 3342, com célula de carga de 10N foi utilizada e, como protocolo, foi seguida a norma ISO 15.841. Para a análise estatística dos resultados foram utilizados os testes: Kolmogorov-Smirnov, para conferir se havia normalidade; teste t independente, para comparação dos resultados do teste de 3 pontos e dos resultados do dispositivo; e o teste ANOVA seguido do teste de Tukey, para comparações entre grupos. RESULTADOS: Houve diferença estatística entre os resultados gerados pelo teste de 3 pontos e os gerados pelo dispositivo. Por ser o teste indicado pela norma ISO citada, somente os resultados do teste de 3 pontos foram considerados. Todos os fios estudados apresentaram pseudoelasticidade em uma faixa de variação de força de até 40cN. Os grupos Abzil convencional, GAC convencional, Morelli termoativado, Ormco CuNiTi e Orthometric convencional apresentaram força dentro de uma faixa considerada ótima para a indução da movimentação dentária (50cN-100cN). Os fios termoativados liberaram forças mais leves que seus pares convencionais. CONCLUSÕES: Dentre os grupos estudados, aqueles que apresentaram pseudoelasticidade...
OBJECTIVE: The purpose of this study was to present the magnitude and the constancy of the forces released by nickel-titanium orthodontic wires, used to treat dental crowding. Another purpose was to compare the most usual types of bending tests used to evaluate these wires: 3-point test and clinical simulation device. MATERIAL AND METHODS: Eleven groups of orthodontic nickel-titanium wires, caliber 0.014, of 6 different brands (Abzil conventional and heat-activated; GAC conventional and heat-activated; Morelli conventional and heat-activated; Ormco CuNiTi; Orthometric conventional and heat-activated and Orthosource conventional and heat-activated) were tested by bending test, at deflections of 0.5; 1; 2 and 3mm. A universal testing machine INSTRON 3342 with a 10N load cell was used and, in order to standardize the tests, the ISO 15.841 regulation was followed. Statistical analysis was performed using the subsequent tests: Kolmogorov-Smirnov to verify normality; independent t test to compare the results of the 3-point test and the results derived from the device, and ANOVA followed by the Tukey test for intergroup comparisons. RESULTS: There were significant differences between the results of the 3-point test and the device. As indicated by the ISO regulation, only the results from the 3-point bending test were considered. All groups were classified as pseudoelastic, within a load range of 40cN, at maximum. The groups Abzil conventional, GAC conventional, Morelli heat-activated, Ormco CuNiTi and Orthometric conventional released load within optimum range (50cN-100cN). Heatactivated wires released lower load compared to conventional wire of the same brand. CONCLUSIONS: Among the groups evaluated those that presented pseudoelasticity, load within a range considered optimal, in a homogeneous manner, were Morelli heat-activated and Ormco CuNiTi.
Subject(s)
Humans , Nickel/chemistry , Orthodontic Wires , Titanium/chemistry , Elastic Modulus , Materials Testing , Malocclusion/therapy , Statistics, NonparametricABSTRACT
Copper NiTi wires were introduced by Sachdeva R and Miyasaki S in 1994. This latest innovation in the evolutionary scale gives us the opportunity of choosing the force level by choosing the temperature at which the wires will deliver its optimum force level. With so many advantages and their ability to return to their original form coupled with the high cost of copper NiTi many clinicians started reusing the wire. This raises concern about disinfecting/sterilizing the wire before using in another patient for prevention of cross infection. Hence, various sterilization procedures like cold sterilization using 2% acidic glutaraldehyde, dry heat sterilization and autoclaving were used to prevent this cross infection..Aim: The main aim of this study is used to evaluate the effects of different kinds of sterilization on load characteristics and tensile properties of copper Ni Ti wire. Materials and Methods: In the present study, selected mechanical properties like load deflection characteristics, ultimate tensile strength of the 0.016 copper NiTi wires were studied before and after sterilization procedure. Three point bending test was performed to evaluate the load deflection characteristics and tensile test were evaluated to determine other mechanical properties. Pretreatment and post treatment values were statistically analyzed by one way ANOVA test. Results: On the load deflection characteristics, even though there was an increase in the loading and unloading forces, statistically significant changes in the forces are seen only when the wires were subjected to two cycles of sterilization with autoclave and dry heat. No detrimental changes were detected in tensile properties of copper NiTi were after single cycle of sterilization with any of the stated sterilants. Very minimal non significant changes occurred during the second cycle of sterilization procedure. Conclusion: Pronounced changes in load deflection characteristics have been found in the wires which have undergone two cycles of sterilization with either dry heat or autoclave implying that there was loss in pseudoplastic and pseudoelastic properties of wires and increase in stiffness of wires.
ABSTRACT
Objetivou-se nessa pesquisa comparar oito tipos de fios de NiTi superelásticos e termoativos, de seis empresas comerciais (GAC, TP, ORMCO, MASEL, MORELLI e UNITEK) àqueles com adição de cobre (CuNiTi 27 e 35OC, ORMCO), observando se as propriedades mecânicas dos dois últimos justificariam sua escolha clínica. Para tal foram realizados ensaios de tração e microscopia eletrônica de varredura. Os ensaios de tração foram realizados em máquina de ensaios mecânicos da marca EMIC, modelo DL10000, de 10 toneladas de capacidade, no Instituto Militar de Engenharia (IME). A composição química e a topografia superficial dos fios foram determinadas através da microscopia eletrônica de varredura em microscópio da marca JEOL, modelo JSM-5800 LV com sistema de microanálise EDS (energy dispersive spectroscopy). Os resultados mostraram que, de forma geral, os fios de NiTi termoativados apresentaram cargas mais suaves de desativação em relação aos superelásticos. Entre os fios que apresentaram as cargas biologicamente mais adequadas de desativação estão os termoativados da GAC e da UNITEK. Entre os fios de NiTi superelásticos, os de CuNiTi 27ºC da ORMCO foram os que apresentaram as cargas mais suaves de desativação, sendo semelhantes, estatisticamente (ANOVA), às apresentadas pelos fios de NiTi termoativados da UNITEK para a deformação de 4%. Quando comparados os fios de CuNiTi a 27 e a 35ºC, observou-se que os primeiros apresentaram forças de desativação de, aproximadamente, 1/3 das apresentadas pelos últimos, para a deformação de 4%. Quando analisada a microscopia eletrônica de varredura de superfície, os fios de NiTi superelásticos que apresentaram melhores acabamentos foram os da MASEL e MORELLI e os que apresentaram os piores acabamentos foram os de NiTi e CuNiTi 27ºC da ORMCO...
Leveling and aligning orthodontic wires must be able to generate light and continuous forces. Thus need to have high springback and flexibility. For this purpose it was suggested a variety of supereslatic and termoactivated Nickel-Titanium (NiTi) wires that may offer a load-deformation curve, in a constant plataform. Copper NiTi wires are presented as exhibiting better thermoactivating properties for optimum-forces system with better dental movement control. The aim of this study was to compare 8 NiTi superelastic and thermoactivated wires of six different brands (GAC, TP, ORMCO, MASEL, MORELLI and UNITEK) to Copper addicted wires (CuNiTi 270C and 350C, ORMCO) to verify if the mechanical properties of Copper NiTi would support its clinical use. Stress-strain tests were done in Engeneering Military Institute (IME-Brazil), through test machine (EMIC- DL 10000 model). Scanning electronic microscope with energy dispersive spectroscopy (JOEL, JSM-5800 LV model) was used to determine chemical composition and superficial topography of the wires. Results showed that, in general, thermoactivated NiTi wires exhibited lower deactivation loads when compared to NiTi superelastics. Among the thermoactivated, the GAC and UNITEK ones are the lighter ones. Among the superelastics, the Copper NiTi 270C (ORMCO) were the lighter ones, statistically similar (ANOVA) to thermoactivated NiTi from UNITEK, for 4% strain. Once Copper NiTi 270C showed deactivated loads 62% lower than Copper NiTi 350C , under 4% strain. As regard to Scanning Electronic Microscopy results for superelastic NiTi wires, better superficial burnishing were found for MASEL and MORELLI ones...