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Objetivo: Avaliar e comparar o atrito entre braquetes ortodônticos (convencional e impressos) e fio de aço. A hipótese nula (H0) é que a média de forças de atrito sejam iguais entre os grupos. Material e Método: O ensaio mecânico foi realizado com 3 grupos de braquetes distintos. Sendo eles: Grupo de braquetes convencional como referência o ClarityTM Advanced (3M Unitek), comparado com dois grupos de braquetes impressos em impressora 3D o Lightforce White (Lightforce Orthodontics) e Lightforce Translucent (Lightforce Orthodontics). As amostras de cada grupo possuem um N=10; os braquetes usados são referentes ao dente 23 (U23) com slot 0.022 e prescrição MBT. O fio ortodôntico foi o de aço inoxidável (CrNi) com calibre de 0.019"x 0.025". O conjunto braquete/fio, unido por ligadura elastomérica, foi colado ao dispositivo de teste, desenvolvido em CAD e impresso em 3D com resina sensível a luz UV, totalizando 30 amostras. Cada amostra foi adaptada a máquina universal de ensaio (EMIC DL ­ 2000) com deslocamento de 2,0mm e velocidade de 1,0mm/min, para mensurar o atrito causado pelo deslize. A força (N) representada pelo pico de cada amostra e, então, realizados a média e o desvio padrão. A comparação foi realizada em nível de significância α = 0,05. A análise de variância ANOVA foi usada para determinar se houve diferenças entre as amostras e o teste post-hoc Tukey. Resultados: µ=0,121N para o Clarity, µ=0,173N para o Lightforce White e µ=0,189N para o Lightforce Translucent. Conclusão: Os braquetes impressos não apresentaram diferença significativa entre eles, porém houve uma pequena diferença para os braquetes do grupo controle que apresentaram uma resistência menor ao deslize do arco (AU)

Purpose: To evaluate and compare the friction between orthodontic brackets (conventional and imprinted) and steel wire. The null hypothesis (H0) is that the average friction forces between the groups are equal. Material and method: The mechanical test was performed with 3 different groups of brackets. These are: Conventional bracket group as reference, ClarityTM Advanced (3M Unitek), compared to two groups of 3D printer printed brackets, Lightforce White (Lightforce Orthodontics) and Lightforce Translucent (Lightforce Orthodontics). The samples from each group have an N=10, and the brackets used are for tooth 23 (U23) with slot 0.022 and MBT prescription. The orthodontic wire was stainless steel (CrNi) with a thickness of 0.019" x 0.025". The bracket/wire set, connected by an elastic ligature, was bonded to the test fixture, which was designed in CAD and 3D printed with UV light-sensitive resin. A total of 30 specimens were fabricated. Each specimen was mounted on a universal testing machine (EMIC DL - 2000) with a displacement of 2.0 mm and a speed of 1.0 mm/min to measure the friction caused by the slide. The force (N) represented by the peak value of each sample, mean and standard deviation were calculated. The comparison was performed with a significance level of α = 0.05. The ANOVA analysis of variance was used to determine if there were differences between samples, and the Tukey test was performed post hoc. Results: µ=0.121N for Clarity, µ=0.173N for Lightforce White, and µ=0.189N for Lightforce Translucent. Conclusion: The printed brackets did not show significant differences. However, there was a small difference in the brackets of the control group, which showed less resistance to arch wire slippage (AU)

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This study aimed to evaluate possible changes in final retention after nine sequences of insertion and removal (SIR) of a frictional Morse taper implant/abutment system, evaluating the force required for dissociating this set between sequences, and verifying possible deformations in the implant heads. Ten implants, 13 mm long and 3.3 mm in diameter, were coupled to a universal mechanical testing machine. Ten anti-rotational abutments, 13 mm long and 3.5 mm in diameter, were connected to the implants parallel to the long axis, using an instrument called beat-connection, and subjected to tensile tests and SEM analysis. The results were analyzed using the Kruskal-Wallis test with Dunn's post-test, and the significance level was set at 5 %. There was no statistically significant difference in final retention among the nine SIRs evaluated. The force needed to uncouple the abutment from the implant increased as SIRs were performed on all ten implants, and an increase of 29.03 % was observed in the ninth SIR compared to the first SIR. After SEM analysis, no significant deformations, fractures, or cracks were observed in the implant heads.

Este estudio tuvo como objetivo evaluar los posibles cambios en la retención final después de nueve secuencias de inserción y extracción (SIR) de un sistema de implante / pilar de cono de fricción Morse, evaluando la fuerza necesaria para disociar este conjunto entre secuencias y verificando posibles deformaciones en las cabezas de los implantes. Se acoplaron diez implantes, de 13 mm de largo y 3,3 mm de diámetro, a una máquina universal de ensayos mecánicos. Se conectaron a los implantes en paralelo al eje largo diez pilares antirrotacionales, de 13 mm de largo y 3,5 mm de diámetro, mediante un instrumento llamado beat-connection, y se sometieron a pruebas de tracción y análisis SEM. Los resultados se analizaron mediante la prueba de Kruskal-Wallis con la prueba posterior de Dunn, y el nivel de significancia se estableció en 5 %. No hubo diferencias estadísticamente significativas en la retención final entre los nueve SIR evaluados. La fuerza necesaria para desacoplar el pilar del implante aumentó a medida que se realizaban SIR en los diez implantes, y se observó un aumento del 29,03 % en el noveno SIR en comparación con el primer SIR. Después del análisis SEM, no se observaron deformaciones, fracturas o grietas significativas en las cabezas de los implantes.

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Objetivo: analizar la producción de literatura científica respecto a la fricción en ortodoncia en los últimos 10 años, a través del estudio de indicadores bibliométricos, tales como: producción anual de artículos, revistas; autores, cooperación entre autores, países que cooperan, instituciones asociadas a las investigaciones, análisis de citas y co-ocurrencia. Métodos: se realizó un estudio bibliométrico descriptivo, retrospectivo de las bases de datos Web of Science y Pubmed, con una ventana de tiempo de 2010 a 2019. Luego de identificar todos los artículos sobre fricción en ortodoncia, se revisaron las variables de producción anual de artículos, revistas, autores, cooperación, países, instituciones, análisis de citas y co-ocurrencia. Para el análisis se utilizó Excel 2013 y VOSviewer 1.6.15, este último es un software gratuito para el análisis de datos bibliométricos. Resultados: para ambas bases de datos, el año de mayor producción en el tema fue 2015; la revista identificada con mayor cantidad de artículos fue Angle Orthodontics; Bourauel Christoph es el principal autor. Brasil fue el país con más publicaciones asociadas a este tema. Las instituciones que más publicaron para Web of Science y Pubmed fueron la Universidad de Bonn y la Universidad Nacional de Seoul. Respecto al análisis de co-ocurrencia, en ambas bases se encontró como variable común el bracket de autoligado, movimiento, tratamiento, sistema, y superficie. Conclusión: la actual producción de publicaciones sobre la fricción en ortodoncia indica una pobre producción de publicaciones en la temática. De esta manera, se destaca que la investigación en fricción sigue en desarrollo gracias a un grupo mínimo de científicos productivos que abordan aspectos que podrían ser de interés para otros investigadores.

Objective: To analyze with some bibliometric indicators (annual production of articles, journals, authors, cooperation, countries, institutions, citation analysis and co-concurrency) production in the scientific literature on the subject of friction in orthodontics over the past 10 years. Methods: A descriptive, retrospective bibliometric study of two databases Web of Science and PubMed with time window 2010 to 2019 was performed. All articles on friction in orthodontics were identified and the variables of annual article production, journals, authors, cooperation, countries, institutions, citation analysis and co-occurrence were reviewed. Excel 2013, VOSviewer 1.6.15 which is a free software for bibliometric data analysis was used for the analysis. Results: The year of the highest production on the subject since the period studied was 2015 and the magazine with the most articles is the Angle Orthodontics for both databases. Bourauel Christoph is the main author. Brazil is the country with the most publications. Among the institutions that publish the most for Web of Science is the University of Bonn and Seoul National University for Pubmed. In co-occurrence analysis, it was found in common for both self-ligating bracket, movement, treatment, system, and surface databases. Conclusion: There is an output of publications on friction in orthodontics that indicates little relevance to the current topic. In this way it is emphasized that frictional research is still in development with a minimal group of productive scientists in aspects that may be of interest to other researchers.

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Abstract Objective: To evaluate the rate of tooth movement and the pain perception via self-ligating (SL) and conventional elastomeric ligation brackets (CB) system. Material and Methods: This study has been conducted at the Orthodontic Department of Baqai Dental College, Baqai Medical University. The sample size of this study comprised 40 patients, falling between the age of 12-30 years without any sex discrimination. Shapiro-Wilk was used to check the distribution of data. Non-parametric Mann Whitney U test was applied to evaluate the pain associated with SL and CB brackets system. To analysis the canine retraction Wilcoxon test was applied for the comparison of CB and SL brackets system. For all statistical analyses, the p-value of <0.05 was considered significant. Results: Pain level associated with retraction via CB and SL shows significant differences. However, the rate of canine retraction via CB and SL shows no significant differences at stages T0-T1 and T1-T2. However, stage T2-T3 shows a significant difference. Conclusion: As pain during orthodontic treatment is mostly associated with the level of compression of the periodontal ligament, it may be hypothesized that lower frictional forces generate less compression of the periodontal ligament and blood vessels, and so alter the type of pain experienced.

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O objetivo do estudo foi comparar a força de atrito de três diferentes marcas de bráquetes convencionais (prescrição Roth) com fio de aço inoxidável 0.019" x 0.025". Num total de 60 bráquetes metálicos de segundos pré-molares superiores com prescrição Roth, sendo 20 bráquetes do modelo Standart (Morelli, São Paulo, Brasil), 20 bráquetes do modelo Agile (Abzil, São Paulo, Brasil) e 20 bráquetes do modelo Synergy (Rock Mountain Orthodontics, Colorado, EUA), slot 0.022" x 0.028", foram colados em um cilindro metálico e posteriormente tracionado por uma máquina Universal Instron DL 100KN para tração (EMIC, Paraná, Brasil), com velocidade de 10 mm/min a uma distância de 10 mm. A análise estatística empregou o teste de Kruskal-Wallis com nível de significância de 5%. Os bráquetes da marca Abzil demostraram o maior valor médio de força de atrito (1,5N) em relação aos bráquetes das outras marcas testadas. Os bráquetes da marca Morelli demostraram um valor intermediário, significativamente diferente, em relação às demais marcas (1,15N), e os bráquetes da marca Rock Mountain Orthodontics, o menor valor médio (0,90N). Os bráquetes da marca Rock Mountain Orthodontics apresentaram o menor valor de força de atrito em relação às outras duas marcas testadas, e os bráquetes da marca Abzil o maior valor. Contudo, não foi observada diferença estatisticamente significativa entre as marcas Morelli e Rock Mountain Orthodontics, no que se refere à força de atrito.(AU)

The objective of this study was to compare frictional force of three different brands of standard brackets with 0.019" x 0.025" stainless steel wire (Roth prescription). A total of 60 conventional upper premolar standard brackets with Roth prescription, 20 Standard brackets (Morelli, São Paulo, Brasil), 20 Agile brackets (Abzil, São Paulo, Brasil), and 20 Synergy brackets (Rock Mountain Orthodontics, Colorado, USA), slot 0.022" x 0.028" were bonded to a metallic cylinder and sequentially tractioned tested for frictional resistance by a Universal Instron DL 100KN machine (EMIC, Paraná, Brasil) for traction, with 10 mm/min speed and 10 mm distance. Statistical analysis employed Kruskal-Wallis test with 5% level of confidence. Abzil brackets demonstrated the highest average frictional force (1,5N) when related to other brands tested. Morelli brackets demonstrated an intermediate value, significantly different (1,5N) in relation to other brands. Rock Mountain Orthodontic brackets demonstrated the smallest mean value (0,90N). Rock Mountain Orthodontics brackets presented the smallest frictional force when compared to the two other brands tested in the study, and Abzil brackets presented the highest value. However, there was no statistical difference between Morelli and Rock Mountain Orthodontics regarding to frictional force.(AU)

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Aim: The aim of this study was to verify the frictional force during sliding mechanics in orthodontic tooth movement, using conventional metal brackets of the active and passive self-ligating types with stainless steel and copper nickel titanium archwires. Methods: This experimental in vitro study was conducted with conventional metal (Morelli, Sorocaba, SP, Brazil) brackets, active self-ligated (SLI Morelli, Sorocaba, SP, Brazil) and passive self-ligated (SLP Morelli, Sorocaba, SP, Brazil), with slot 0.022 x 0.028 inches and Roth prescription. The brackets were tested with rectangular section 0.019 x 0.025 inch copper nickel titanium and stainless steel archwires. For each type of bracket, 10 sets of plate/bracket/archwire segment (n=10) were fabricated. Non-parametric Kruskal Wallis and Dunn tests were used for comparison between types of brackets and Wilcoxon tests for comparison between types of archwires. Results: The results showed that the frictional force values were higher with copper nickel titanium than with stainless steel archwires (p<0.05). When copper nickel titanium archwires were used, the active self-ligating brackets showed higher frictional force values than the other types, followed by the conventional brackets. Lower frictional force values were observed with passive self-ligating brackets. For stainless steel archwires, no difference was observed between conventional and active self-ligating brackets, the passive self-ligating type presented lower frictional force values than the others. Conclusion: It was concluded that the higher frictional force was observed when active self-ligating brackets were associated with copper nickel titanium archwires. Lower frictional force was verified between passive self-ligating brackets combined with stainless steel archwires

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La técnica ortodóncica de baja fricción utiliza brackets pasivos de autoligado con una serie de arcos superelásticos que mantienen las fuerzas aplicadas sobre las piezas dentarias a nivel de la "biozona o zona fuerza óptima". La utilización de gomas intermaxilares ligeras (2 onzas o 56,68 g) en estos tratamientos, desde etapas iniciales, sobre todo en pacientes en crecimiento, permite obtener resultados muy favorables en cuanto a la resolución de la maloclusión de Clase II. Objetivo: evaluar el tratamiento de Ortodoncia de un paciente Clase II esqueletal con sobremordida, sin realizar exodoncias de premolares y utilizando elásticos intermaxilares en fases iniciales de tratamiento. Materiales y método: se presenta el caso clínico de un paciente de sexo masculino de 11 años, de Clase II esqueletal con sobremordida y apiñamiento dentario anterior superior e inferior moderado, con su diagnóstico y evaluación completos pre y post tratamiento y control y seguimiento al año. El tratamiento se realiza con brackets autoligantes (técnica de Damon). Resultados: se obtiene la corrección completa de la Clase II y la sobremordida, alcanzando los objetivos deseados de estética facial y función, en oclusión y desoclusiones, con buen desarrollo de las basales y conservación de la altura de las corticales alveolares a nivel de los caninos. Conclusión: Mediante los recursos terapéuticos disponibles en la actualidad y evaluando al niño en etapas tempranas, podremos combinar diferentes tratamientos para alcanzar los objetivos propuestos en menor tiempo y con óptimos resultados en una maloclusión de Clase II con sobremordida con biotipo mesofacial (AU)

The low friction orthodontic technique uses passive self-ligating brackets with a series of superelastic arches that maintain the forces applied to the dental pieces at the "Biozone or Optimal Force Zone". The use of inter maxillary light elastics (2 ounces or 56.68 yr.) from the initial stages in growing patients, yields very favorable results in terms of correction of Class II malocclusion. Objective: To assess the orthodontic treatment of a skeletal Class II patient with overbite, without extraction of premolars and using elastic in the early stages of treatment. Materials and methods: an 11 year old male skeletal Class II patient with overbite and moderate crowding in upper and lower anterior teeth, with complete diagnostic and evaluation before and after treatment and with annual control. For the treatment, self-ligating brackets (Damon technique) were employed. The results: Total correction of Class II condition and overbite was obtained. The desired goals of facial aesthetics and correct function were attained in occlusion and desocclusion, as well as development of the osseous basis and conservation of the canine alveolar cortical height. Conclusion: Through the employment of therapeutic resources available at present and following up the child through his developmental stages, it is possible to combine different treatments to achieve the proposed objectives in a shorter time with excellent results in mesofacial type patients with Class II malocclusion and deep overbite (AU)

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El movimiento ortodóncico es el resultado de la aplicación de fuerzas a las piezas dentarias a través de dispositivos diseñados para almacenar energía y devolverla y, así, producir el efecto deseado. El profesional actuante puede confeccionar un diagnóstico e implementar una técnica para concretar un plan de tratamiento y cumplir las satisfacciones estéticas del paciente eligiendo el zafiro como material de innovación. Sin embargo, si el bracket de zafiro no mantiene su integridad estructural en el slot donde se encuentra la información para el movimiento de la pieza dentaria, el ortodoncista debe hacer maniobras compensatorias en busca del movimiento dental óptimo para alcanzar el éxito deseado. El objetivo de este trabajo fue comparar la angulación de las paredes del slot de los brackets de zafiro y el desgaste en la superficie estructural del material en brackets sin uso clínico y utilizados luego de concluir un tratamiento. Para esto, se eligieron brackets de zafiro de todas las piezas dentarias de la arcada del maxilar superior y del inferior con uso y sin uso clínico y fueron observados al microscopio electrónico de barrido ambiental (MEB) FEI ESEM Quanta 200. Las muestras fueron lavadas con alcohol absoluto de 96 % de volumen, cepilladas de manera mecánica y secadas antes de ser introducidas en la cámara del MEB. En la etapa de observación se procedió a la construcción de medidas lineales en la imagen de la ranura del bracket desde una vista sagital. Se obtuvieron una medida interna, una media y una externa, cuyos resultados se analizaron mediante el test de normalidad de Shapiro-Wilk. En conclusión, mediante este estudio se observó que algunos brackets mantuvieron su estructura al inicio y al final de su utilización clínica, y otros presentaron una diferenciación en la medida inicial del grupo de brackets no usados clínicamente, que lleva a determinar un desgaste del ángulo interno del slot producto del deslizamiento del alambre durante el uso clínico.

The orthodontic movement is the result of the application of forces to the dental pieces through devices designed to store energy and return it and so to produce the desired effect. The acting professional can make a diagnosis and implement a technique to carry out a treatment plan and meet the aesthetic satisfactions of the patient choosing sapphire as an innovation material. However, if the sapphire bracket does not maintain its structural integrity in the slot where the information for the movement of the tooth is located, the orthodontist must make compensatory maneuvers in search of optimal dental movement to achieve the wanted success. The objective of this work was to compare the angulation of the sapphire brackets slot walls and the wear on the structural surface of the brackets material without clinical use and used after completing a treatment. For this, sapphire brackets were selected from all teeth of the upper and lower jaw arches with use and without clinical use and were observed under the environmental scanning electron microscope (ESEM) FEI ESEM Quanta 200. Samples were washed with absolute alcohol at 96% vol, mechanically brushed and dried before being introduced into the MEB chamber. In the observation phase it was carried out the construction of linear measurements in the image of the bracket slot from a sagittal view. They were obtained an internal, an average and an external measurements which results were analyzed by the Shapiro-Wilk Normality Test. In conclusion, through this study it was observed that some brackets maintained their structure at the beginning and end of their clinical use and others presented a differentiation in the initial measurement of the group of not used clinically brackets that leads to determine a wear of the internal angle of the slot owing to the sliding of the wire during clinical use.

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The aim of this study was to use a 3D finite element method (FEM) to compare the sliding resistance of 0.019"x0.025" stainless steel conventional archwires versus 0.019"x0.025" stainless steel beveled archwires in active (InOvation ® Dentsply) and passive (SmartClip®, 3M) selfligating brackets with 0.022" x 0.028" slots . A model was designed for each kind of bracket archwire system and the following parameters were introduced in the models: friction coefficient calculated for stainless steel bracketwire: 0.7 µm; Poisson ratio for stainless steel wire: 0.3, and elastic module: 205 GPa for bracket and 190 GPa for archwire. Static structural analysis was applied for homogeneous, linear and isotropic properties considering contacts between wire and bracket as frictional. The results indicate that the beveled archwire generates less stress than the rectangular wire in SmartClip® and InOvation ® brackets. Comparing brackets, SmartClip® generated less stress than InOvation ®. It is concluded that beveled rectangular arch wires provide the advantage of reduced sliding resistance, which is better in some clinical situations to improve orthodontic mechanics (AU)

El objetivo de este artículo fue comparar con el método tridimensional de elementos finitos (MEF) el comportamiento de la resistencia al deslizamiento expresado en esfuerzos de arcos de acero inoxidable 0.019"x0.025" convencionales y arcos de acero inoxidable con bisel de 0.019"x0.025" en brackets de autoligado slot 0.022" x 0.028" activo (InOvation ® "R" Dentsply) y pasivo (SmartClip® 3M). Se diseñó un modelo de los brackets de autoligado InOvation® "R" Dentsply, SmartClip® 3M y de los arcos de acero inoxidable convencionales y arcos de acero inoxidable con bisel, el análisis se calculó con el coeficiente de fricción para el bracket de acero inoxidable con el del arco de acero inoxidable: µ 0.7. La relación de Poisson 0.3 para el arco de acero inoxidable. El módulo de elasticidad del bracket: 205 GPa y del arco: 190 GPa. La aplicación del método se realizó para un análisis estructural estático con condiciones de material homogéneas, lineales e isotrópicas y con contactos de tipo fricción entre el arco y el bracket. Se observó que el arco biselado generó menos esfuerzo que el arco rectangular en el bracket SmartClip® y en el bracket InOvation ® "R", siendo el SmartClip® en el que se generó menor esfuerzo. Se encontró que existe una ventaja en el uso de los arcos rectangulares con bisel ya que presentan menor resistencia al deslizamiento optimizando en algunas situaciones clínicas las mecánicas ortodónticas (AU)

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La mecánica de deslizamiento es muy utilizada durante el tratamiento ortodóntico. Una de las desventajas de esta mecánica es l a fricción generada entre la interfaz del bracket y del arco, lo que puede reducir la cantidad de movimiento deseado. Debido a la aplicación y la gran aceptación de este tipo de mecanismos, la fricción en ortodoncia es de interés tanto para los ortodoncistas e investigadores en ortodoncia. El objetivo del presente trabajo fue, realizar una revisión de la literatura científica sobre "Fricción", y explicar cómo la fricción afecta al movimiento ortodóntico de los dientes, con una aproximación a sus implicancias clínicas, así como la evolución de los materiales dentales y sus propiedades en cuanto a la resistencia al deslizamiento. Describimos las propiedades físicas de fricción, los tipos de fricción, los factores biológicos, elementos que influyen en la fricción: material de ligadura, alambres y tipos de brackets. También describimos la fricción en las diferentes etapas del tratamiento ortodóntico: alineación y nivelación (fase inicial), cierre de espacios (fase intermedia), y finalización (fase final). La fricción en ortodoncia, representa un reto clínico para los ortodoncistas, porque los altos niveles de fricción pueden reducir la eficacia de la mecánica, disminuir la eficiencia delos dientes y complicar aún más el control de anclaje. La presente revisión de literatura busca aclarar los conceptos de fricción, buscando las condiciones ideales para realizar el movimiento dentario en la práctica diaria de la ortodoncia, seleccionando los materiales y aparatos adecuados, para aplicarlos en forma eficiente, eficaz y efectiva en la búsqueda de las condiciones ideales para el éxito del tratamiento ortodóntico. (AU)

The sliding mechanics is used during orthodontic treatment. A disadvantage of this mechanical friction is generated in the bra cket and interfacez of arc, which can reduce the amount of desired movement. Due to the wide acceptance and implementation of these mechanisms, friction in orthodontics has been of interest to both clinicians and scientists. The aim of this paper is a review of the scientific literature on "Friction" and explains how friction affects the orthodontic movement of teeth, with an approach to its clinical implications, and the evolution of dental materials and their properties regarding the resistance to sliding. Describes the physical properties of friction, friction rate, biological factors, and elements influencing the friction: ligature material, wires and brackets types. We also describe the friction in the different stages of orthodontic treatment: alignment and leveling (initial phase), space closure (intermediate phase), and end (final phase). The friction in orthodontics represents a clinical challenge for orthodontists, because high levels of friction can reduce the effectiveness of mechanical efficiency decrease teeth and further complicate anchorage control. This paper seeks to clarify the concepts of friction, looking for the ideal conditions for tooth movement in daily practice oforthodontics, selecting materials and equipment suitable for application in an efficien t, effective and efficient in finding the ideal conditions for orthodontic treatment success. (AU)

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