Producción científica sobre el abordaje de la fricción en ortodoncia. Estudio de revisión con indicadores bibliométricos / Scientific production on friction in orthodontics. Review study with bibliometric indicators

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.

Pain Perception and Rate of Canine Retraction Through Self-Ligating Brackets and Conventional Elastomeric Ligation System: A Split Mouth Study

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.

Evaluation of friction on self-ligating and conventional brackets associated with different types of archwires submitted to sliding mechanics

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

Tratamiento de Clase II con Ortodoncia Sistema Damon y gomas intermaxilares en etapas tempranas de tratamiento / Treatment of Class II with Orthodontics Damon System and elastics in early stages of treatment

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)

Estudio en el microscopio electrónico de barrido de los brackets zafiro / Scanning electron microscopic study of the sapphire brackets

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.

A biomechanical case study on the optimal orthodontic force on the maxillary canine tooth based on finite element analysis / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Excessive forces may cause root resorption and insufficient forces would introduce no effect in orthodontics. The objective of this study was to investigate the optimal orthodontic forces on a maxillary canine, using hydrostatic stress and logarithmic strain of the periodontal ligament (PDL) as indicators. Finite element models of a maxillary canine and surrounding tissues were developed. Distal translation/tipping forces, labial translation/tipping forces, and extrusion forces ranging from 0 to 300 g (100 g=0.98 N) were applied to the canine, as well as the force moment around the canine long axis ranging from 0 to 300 g·mm. The stress/strain of the PDL was quantified by nonlinear finite element analysis, and an absolute stress range between 0.47 kPa (capillary pressure) and 12.8 kPa (80% of human systolic blood pressure) was considered to be optimal, whereas an absolute strain exceeding 0.24% (80% of peak strain during canine maximal moving velocity) was considered optimal strain. The stress/strain distributions within the PDL were acquired for various canine movements, and the optimal orthodontic forces were calculated. As a result the optimal tipping forces (40-44 g for distal-direction and 28-32 g for labial-direction) were smaller than the translation forces (130-137 g for distal-direction and 110-124 g for labial-direction). In addition, the optimal forces for labial-direction motion (110-124 g for translation and 28-32 g for tipping) were smaller than those for distal-direction motion (130-137 g for translation and 40-44 g for tipping). Compared with previous results, the force interval was smaller than before and was therefore more conducive to the guidance of clinical treatment. The finite element analysis results provide new insights into orthodontic biomechanics and could help to optimize orthodontic treatment plans.

Sliding resistance of rectangular vs. beveled archwires in two self-ligating brackets: a finite element study

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)

Fricción en ortodoncia / Friction in orthodontic

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)

Understanding the basis of space closure in Orthodontics for a more efficient orthodontic treatment

ABSTRACT Introduction: Space closure is one of the most challenging processes in Orthodontics and requires a solid comprehension of biomechanics in order to avoid undesirable side effects. Understanding the biomechanical basis of space closure better enables clinicians to determine anchorage and treatment options. In spite of the variety of appliance designs, space closure can be performed by means of friction or frictionless mechanics, and each technique has its advantages and disadvantages. Friction mechanics or sliding mechanics is attractive because of its simplicity; the space site is closed by means of elastics or coil springs to provide force, and the brackets slide on the orthodontic archwire. On the other hand, frictionless mechanics uses loop bends to generate force to close the space site, allowing differential moments in the active and reactive units, leading to a less or more anchorage control, depending on the situation. Objective: This article will discuss various theoretical aspects and methods of space closure based on biomechanical concepts.

RESUMO Introdução: O fechamento de espaços é um dos processos mais desafiadores na Ortodontia e requer uma compreensão sólida de conceitos biomecânicos, a fim de se evitar efeitos colaterais indesejáveis. Compreender o fundamento biomecânico do fechamento de espaços possibilita uma melhor definição das opções de ancoragem e tratamento, por parte dos clínicos. Apesar de haver uma variedade de desenhos de aparelhos ortodônticos, o fechamento de espaços pode ser realizado por meio da mecânica com atrito ou sem atrito, e cada técnica apresenta vantagens e desvantagens. A mecânica com atrito, ou mecânica de deslizamento, é atraente em virtude de sua facilidade, o espaço é fechado por meio do uso de elásticos ou molas helicoidais, que produzem força, fazendo com que os braquetes deslizem no arco ortodôntico. Por outro lado, a mecânica sem atrito se utiliza de dobras em alças para gerar força para fechar o espaço, possibilitando momentos diferenciais nas unidades ativa e reativa, induzindo a uma ancoragem mais ou menos controlada, dependendo da situação. Objetivo: o presente artigo discutirá vários aspectos teóricos e métodos de fechamento de espaços, baseando-se em conceitos biomecânicos.

Fricção superficial dos bráquetes autoligados / Surface friction of self-ligated brackets

Este trabalho avalia a fricção superficial dos bráquetes autoligados e bráquetes convencionais, suas vantagens e desvantagens. Alguns estudos avaliaram fatores como: os materiais dos fios e dos bráquetes, as condições da superfície dos fios e do encaixe do bráquete, a secção do fio, o torque na interface fio-bráquete, a angulação dos bráquetes, o tipo e a força da ligadura, a salina e as funções bucais. Estes fatores influenciam na fricção tanto dos bráquetes autoligados como dos bráquetes convencionais, porém todos os bráquetes autoligados mostraram valores de fricção inferiores aos dos bráquetes convencionais, tanto no atrito estático como cinético.

The present paper compares the friction surface of self-ligated brackets and conventional brackets, their advantages and disadvantages, based in studies wich evaluates such factors as the materials of wires and brackets, the surface condition of the wires and the brackets fit, the cable section, the torque on the bracket-wire interface, the angle of the brackets and strength of their ligations, the saline and oral functions. These factors influence the friction of both self-ligated brackets and conventional brackets, but all self-bonded brackets showed lower friction values compared to those of conventional brackets in both (static and kinetic) frictions.