ABSTRACT
Introducción: es importante para el ortodoncista conocer la resistencia al deslizamiento (RD) generada por el método de ligado usado durante la fase de cierre de espacio con mecánica de deslizamiento. El objetivo es comparar in vitro la RD de un tipo de bracket de autoligado con un tipo de bracket convencional combinado con ligaduras elastoméricas de baja fricción y ligaduraelastomérica convencional. Métodos: se utilizaron brackets de autoligado SmartClip (3M®) y brackets convencionales Gemini (3M®), dostipos de ligadura elastomérica de baja fricción Slide (Leone®), Synergy (RMO®) y un tipo de ligadura elastomérica convencional Sani-Tie(GAC®). Los sistemas de ligación de los brackets fueron probados con alambre de acero inoxidable calibre 0,019 × 0,025″. La resistencia al deslizamiento de la combinación bracket/alambre/ligadura fue medida con un modelo experimental de tres brackets cementados en una placa acrílica, montada en una máquina Instron. Cada combinación fue probada 9 veces consecutivas en estado seco. Resultados: los brackets Gemini (3M®) con ligadura convencional Sani-tie (GAC®), reportaron valores promedio de 67,3 g y los brackets Gemini (3M®) con ligadura de baja fricción siliconada Synergy (RMO®) de 84,6 g. Los brackets SmartClip (3M®) y Gemini (3M®) con ligadura elastomérica debaja fricción Slide (Leone®) tuvieron valores promedio similares de 5,0 y 5,4 g, respectivamente, sin diferencias significativas (p = 0,999).Conclusiones: las ligaduras elastoméricas de baja fricción Slide (Leone®), mostraron fuerzas de resistencia al deslizamiento similares alos brackets de autoligado Smartclip (3M).
Introduction: It is important for the orthodontist to be familiar with the sliding resistance (SR) generated by the ligation method used during the space closure phase with sliding mechanics. The objective of this article is to make an in vitro comparison of the SR produced by a self-ligating bracket and a conventional bracket in combination with low-friction and conventional elastomeric ligatures. Methods: SmartClip (3M®) self-ligating brackets and Gemini (3M®) conventional brackets were used, as well as two typesof low-friction elastomeric ligature: Slide (Leone®) and Synergy (RMO®), and one type of conventional elastomeric ligature: Sani-Tie(GAC®).The brackets ligation systems were tested with stainless steel wire of 0.019 × 0.025 caliber. Sliding resistance of the bracketwire-ligature combination was measured with an experimental model of three brackets bonded in an acrylic plate mounted on an Instron machine. Each combination was tested nine consecutive times in dry state. Results: The Gemini (3M®) brackets with a conventionalSani-Tie (GAC®) ligature reported mean values of 67.3 g, while the Gemini (3M®) brackets with low-friction Synergy (RMO®) silicone ligature obtained mean values of 84.6 g. The SmartClip (3M®) and Gemini (3M®) brackets with low-friction Slide (Leone®) elastomeric.
Subject(s)
Friction , OrthodonticsABSTRACT
Context: Tensile properties of elastomeric ligatures become important when efficiency of orthodontic appliances is considered. Aims: The aim of this study was to compare tensile strength, extension to tensile strength, toughness and modulus of elasticity of elastomeric ligatures in both the as-received condition and after 28 days of immersion in the simulated oral environment. Furthermore, the changes that occurred in tensile properties of each brand of ligatures after 28 days were evaluated. Setting and Design : Experimental-laboratory based. Materials and Methods: Elastomeric ligatures were obtained from different companies and their tensile properties were measured using Zwick testing machine in both the as-received condition and after 28 days of immersion in the simulated oral environment. Statistical Analysis Used: The data were analyzed using independent sample t-tests, analysis of variance and Tukey tests. Results: After 28 days, all the ligatures experienced a significant decrease in tensile strength, extension to tensile strength and toughness ( P < 0.05), whereas modulus of elasticity increased in some groups and decreased in others. There were significant differences in tensile properties of different brands of ligatures in both conditions ( P < 0.05), with the exception of modulus of elasticity after 28 days. Conclusions : The decrease in strength properties of elastomeric ligatures shows that they should be replaced at each appointment to reduce the risk of rupture. There are significant differences in tensile properties of different brands of ligatures, which should be considered during selection of these products.
Subject(s)
Analysis of Variance , Dental Stress Analysis , Elastic Modulus , Elastomers , Orthodontic Appliances , Saliva, Artificial , Statistics, Nonparametric , Tensile StrengthABSTRACT
OBJETIVO: avaliar ligaduras elásticas da marca Morelli, dos tipos modular e bengala, nas cores cinza e cristal para determinação do percentual de degradação das forças geradas pelas mesmas. METODOLOGIA: as ligaduras elásticas foram estiradas em estiletes de aço inoxidável com diâmetro de 4mm, imersas em solução de saliva artificial a 37ºC, sendo a intensidade das forças liberadas medidas nos tempos de zero hora, 24 horas, 1 semana, 2 semanas, 3 semanas e 4 semanas, em máquina de ensaios de tração. RESULTADOS E CONCLUSÕES: as ligaduras do tipo bengala liberaram, em média e no período de 4 semanas, maior intensidade de força que as do tipo modular. O percentual de degradação das forças liberadas por todas as ligaduras aumentou de forma acentuada entre zero e 24 horas e de forma gradativa após este período, com exceção do 28º dia quando, provavelmente, houve perda das propriedades elásticas das ligaduras. Não foi observado um comportamento constante das ligaduras bengala e modular em relação às cores cinza e cristal.
PURPOSE: to evaluate gray and clear module and cane-loaded elastomeric ligatures of the brand Morelli to determine the percentage of decay of the forces they deliver. METHODS: the elastomeric ligatures were stretched over 4mm diameter stainless steel dowels and placed in synthetic saliva bath at 37ºC. The intensity of the forces delivered were taken at start, after 24 hours, one week, two weeks, three weeks and four weeks at a tensile test machine. RESULTS AND CONCLUSIONS: the cane-loaded ligatures delivered, in a period of 4 weeks, in average, greater force intensity than the modules. The percentage of force decay of all ligatures increased rapidly between zero and 24 hours and gradually after that period, except for the 28th day, when probably there was a loss of elastic properties of the ligatures. The researchers did not note any constant behavior in the cane-loaded and module ligatures in relation to the colors: gray and clear.