Clinical effect of a door shaped individualized dental archwire on the treatment of maxillary transposed canines / 口腔疾病防治

Objective @#To discuss the effectiveness and mechanism for movement of maxillary buccally transposed canines by using a door-shaped individualized dental archwire mechanic and to provide a reference for clinicians.@*Methods@#Eight patients with unilateral maxillary transposed canines were enrolled. All patients were treated with door-shaped individualized archwires. Before treatment (T1) and after the crowns of the transposed canines were moved to the right buccal positions in the dental arch during the treatment (T2), orthopantomograms were taken both at T1 and T2 to compare the linear changes (distance changes of the crown and root apex) and angular changes to study the mechanisms of tooth movement. The probing depth and buccal crown height were measured using a periodontal probe to compare periodontal changes before treatment (T1) and after treatment (T3) between the transposed canines and contralateral canines. @*Results@# All eight transposed canines were successfully brought back to their normal dental arch position but were made more buccal by using the door-shaped individualized dental archwire, with a mean of (11.5 ± 2.7) months. The average overall duration was (28.3 ± 4.7) months. The crown distance changes of the canines from T1 to T2 (8.1 mm) were greater than those of the root apexes (1.5 mm) (P<0.05). The mean angulation changes of the long axes of the canines were 17.5°. There was no significant difference in the depth of periodontal measurement and buccal crown height measurement between T1 and T3 (P>0.05). @*Conclusion @# The buccal movement of maxillary transposed canines under a door-shaped individualized dental archwire was effective and feasible. The movement pattern under this mechanism was controlled tipping.

Effect of ibuprofen and low-intensity pulsed ultrasound on the reduction of pain after initial archwire placement: a double-blind randomized clinical trial / Efecto del ibuprofeno y el ultrasonido pulsado de baja intensidad en la reducción del dolor después de la colocación inicial del arco de ortodoncia: un ensayo clínico aleatorizado doble ciego

Objective: This study aimed to compare the effect of ibuprofen and low intensity pulsed ultrasound (LIPUS) on the reduction of pain after the placement of initial archwire in orthodontic patients. Material and Methods: This double-blind clinical trial study was carried out on 60 female candidates for fixed orthodontic treatment referring to the Orthodontic Department of School of Dentistry in Mashhad University of Medical Sciences, Mashhad, Iran, during 2015-2016. The subjects were divided into four groups of ibuprofen, LIPUS, placebo, and mock LIPUS. A questionnaire and a rectangular and flexible cubic silicone were given to each patient to record the severity of pain based on the visual analog scale at specified time points (i.e., 2 h, 6 h, at bedtime, 2nd, 3rd, and 7th days after archwire placement) when biting the silicone block with the anterior and posterior teeth and without biting at all. Repeated measures analysis of variance was used in order to compare the pain severity at different time points. Results: The comparison of pain severity at various time points showed that the highest and lowest mean scores of pain were reported at bedtime and seven days after the intervention (p<0.001). In each of the three conditions (i.e., biting the silicone block with the anterior and posterior teeth and without biting the teeth) at six time points (i.e., 2 h, 6 h, at bedtime, 2nd, 3rd, and 7th days following archwire placement), no significant difference was observed in the severity of pain (p>0.05). Conclusion: In conclusion, LIPUS (with a frequency of 1 MHz and an intensity of 100 mW) and ibuprofen have no significant effects on reduction of the pain severity at different time points and various conditions in orthodontic patients.

Objetivo: Este estudio tuvo como objetivo comparar el efecto del ibuprofeno y el ultrasonido pulsado de baja intensidad (LIPUS) en la reducción del dolor después de la colocación del arco inicial en pacientes de ortodoncia. Material y Métodos: Este estudio de ensayo clínico doble ciego se llevó a cabo en 60 candidatas a tratamiento de ortodoncia fija referidas al Departamento de Ortodoncia de la Facultad de Odontología de la Universidad de Ciencias Médicas de Mashhad, Mashhad, Irán, durante 2015-2016. Los sujetos se dividieron en cuatro grupos: ibuprofeno, LIPUS, placebo y LIPUS simulado. Se entregó un cuestionario y un bloque de silicona cúbica rectangular y flexible a cada paciente para registrar la intensidad del dolor según la escala analógica visual en puntos de tiempo específicos (es decir, 2 h, 6 h, hora de acostarse, 2do, 3er y 7mo día después de la colocación del arco) al morder el bloque de silicona con los dientes anteriores y posteriores, y sin morder en absoluto. Se utilizó el análisis de varianza de medidas repetidas para comparar la intensidad del dolor en diferentes momentos.Resultados: La comparación de la intensidad del dolor en varios puntos de tiempo mostró que las puntuaciones medias de dolor más altas y más bajas se informaron a la hora de acostarse y siete días después de la intervención (p<0,001). En cada una de las tres condiciones (es decir, al morder el bloque de silicona con los dientes anteriores y posteriores, y sin morder) en seis momentos (2 h, 6 h, antes de acostarse 2do, 3er y 7mo día después de la colocación del arco), no se observó diferencia significativa en la severidad del dolor (p>0.05).Conclusión: En conclusión, LIPUS (con una frecuencia de 1 MHz y una intensidad de 100 mW) y el ibuprofeno no tienen efectos significativos en la reducción de la severidad del dolor en diferentes puntos de tiempo y diversas condiciones en pacientes de ortodoncia.

Research progress on the three-dimensional finite element analysis of bite opening / 口腔疾病防治

@#Deep bite is a common clinical malocclusion that has a great impact on patients’ facial aesthetics and oral function. Bite opening is the key step in the treatment of deep bite, playing a decisive role in the development of mandible and the progress of orthodontic treatment. Torque and tip control during the correction of deep bites is a hot topic in orthodontics. The three-dimensional finite element method can accurately simulate clinical processes and conduct dynamic stress analysis, which provides the basis of the biomechanical mechanism. This paper reviewed the finite element analysis of various orthodontic systems for bite opening to provide a reference for clinical application. The emergence of mini-implants provided a new idea for anchorage control in bite opening. Finite element studies found that high-positioned mini-implants are beneficial for bodily tooth intrusion and proposed the ideal position for force application. For the finite element simulation of the reverse curve archwire, it was found that the intrusion and inclination of the anterior teeth increased with the curve depth of the archwire. The application of clear aligners has also been flourishing, but these forces are still difficult to effectively control. Finite element studies on their attachment design and corresponding tooth movement may be helpful to open the bite quickly and effectively. However, the existing studies still have modeling limitations. The structural simplification, linearization and nonstandard parameter definition of the model reduce model accuracy. Additionally, the existing research mostly focused on initial tooth movement, and studies on long-term tooth movement after bone remodeling are lacking. These studies are needed in the future.

Pulpal blood flow changes and pain scores related to using Superelastic 0. 018-inch Nickel Titanium as the first orthodontic alignment archwire: a prospective clinical trial

Abstract Background Optimal orthodontic force results in maximum rate of tooth movement without tissue damage. Even though starting orthodontic treatment with a thicker archwire may shorten treatment duration, the evidence on the effect of using 0.018-inch NiTi as the first alignment archwire on pulpal blood flow (PBF) status is still scarce. Objectives to record PBF changes and pain scores associated with using 0.018-inch NiTi as the first alignment archwire during fixed orthodontic treatment. Methodology Patients were selected from subjects attending postgraduate orthodontic teaching clinics at Jordan University of Science and Technology. In total, forty healthy patients who exhibited mild lower arch crowding were included. A split-mouth trial design was used. Each patient received two archwire sizes at one time joined in the midline by crimpable hook and applied in the lower arch. Patients were assigned into one of two groups based on archwire sizes used. Group 1: 0.014-inch and 0.018-inch NiTi (Six males, 14 females aged 19.4±1.33 years) and Group 2: 0.016-inch and 0.018-inch NiTi (Seven males, 13 females aged 19.6±1.45 years). The archwire size group was randomly allocated with a 1:1 allocation ratio. A Laser Doppler Flowmeter was used to measure PBF at different time intervals (T0-T5). Pain scores were recorded using a visual analogue scale (VAS). A repeated measures ANOVA and a post-hoc Bonferroni comparison tests were conducted to examine differences at the different time points before and during orthodontic alignment. Results For all studied archwire sizes, PBF decreased 20 minutes after their placement. Most PBF changes occurred within 24hours and continued to decrease until 72 hours after archwire placement where the maximum reduction was reached. Eventually, normal values were reverted within 1 month. PBF changes were similar between all alignment - groups. Conclusions Initial orthodontic alignment with 0.018-inch NiTi does not cause irreversible changes to pulpal vasculature or produces higher pain scores.

Comparación del tamaño transversal de los arcos 0. 012, 0. 014 y 0. 016 de NiTi de tres marcas / Comparação do tamanho transversal dos arcos 0. 012, 0. 014 e 0.016 de NiTi de três marcas / Comparison of the cross-sectional size of the 0. 012, 0. 014 and 0. 016 NiTi archs of three brands

Objetivo: Determinar si existen diferencias en el tamaño de los arcos de NiTi en los calibres 0.012, 0.014 y 0.016 de tres marcas comerciales. Material y métodos: Se utilizaron 180 arcos de NiTi de las marcas American Orthodontics, TD Orthodontics y OrthoPremium. La estadística descriptiva, la ANOVA y el Post Hoc se realizaron en el programa SPSS 18. Resultados: los arcos de American Orthodontics presentaron diferencias estadísticas significativas en la parte anterior y posterior. En los arcos superiores de TD Orthodontics se encontró contracción en el calibre 0.016. En los arcos superiores OrthoPremium presento una contracción en la parte anterior y en el arco inferior de los 10 a los 40mm. Al comparar las tres marcas se encontraron diferencias estadísticas significativas (p<0.05) entre ellas con las pruebas de ANOVA. Conclusiones: existen diferencias en los tamaños de los arcos superiores e inferiores de cada marca y entre ellas.

Objective: To determine if there are differences between the 0.012, 0.014 and 0.016 NiTi archwires of three brands. Material and methods: 180 NiTi archwires of the following brands were used: American Orthodontics, TD Orthodontics and OrthoPremium. Descriptive statistics, ANOVA and Post Hoc were performed in the SPSS 18 program. Results: The American Orthodontics archwires presented significant statistical differences in the anterior and posterior parts. In the TD Orthodontics upper archwires, contraction was found in the 0.016 caliber. In the upper archwires, OrthoPremium presented a contraction in the anterior part and in the lower archwire of 10 to 40mm. When comparing the three brands, significant statistical differences (p <0.05) were found between them with the ANOVA tests. Conclusions: there are differences in the sizes of the upper and lower archwires of each brand and between them.

Objetivo: determinar se existem diferenças no tamanho dos arcos de NiTi em calibres 0, 12, 0, 14 e 0, 16 de três marcas comerciais. Material e métodos: foram utilizados 180 arcos NiTi das marcas American Orthodontics, TD Orthodontics e OrthoPremium. Estatística descritiva, ANOVA e Post Hoc foram realizadas no programa SPSS 18. Resultados: os arcos da American Orthodontics apresentaram diferenças estatísticas significativas na parte anterior e posterior. Nos arcos superiores da TD Ortodontia foi encontrada contração no calibre 0, 16. Nos arcos superiores, o OrthoPremium apresentou contração na parte anterior e no arco inferior de 10 a 40mm. Ao comparar as três marcas, foram encontradas diferenças estatísticas significativas (p <0,05) entre elas com os testes ANOVA. Conclusões: existem diferenças nos tamanhos dos arcos superior e inferior de cada marca e entre eles.

The Extra-Oral Measuring Technique of Initial Restoring Force Produced by Orthodontic Archwire Based on Dental Model / 医用生物力学

Objective To realize the extra-oral measurement of initial recovery force produced by orthodontic wire using simulated dental model. Methods A clinical patient was selected as the study objective, and maxillary dental models, which were in accordance with the real dentition of patient, were fabricated by three-dimensional printing. An orthodontic force measuring system was constructed using Nano17 F/T mechanical sensors to measure the initial recovery forces on two maxillary central incisors, which were produced by a standard circle Ni-Ti wire with the diameter of 355.6 μm after the archwire was assembled on the dental model. Results Central incisor 21 suffered a lager initial orthodontic force compared with incisor 11, and the force systems on two incisors were both adverse to tooth ideal movement, therefore, an assistive device was necessary to improve force status of the teeth. When the orthodontic treatment plan was optimized, a satisfactory result was obtained after 18 months of treatment. Conclusions Force systems caused by orthodontic wire and exerted on the teeth could be accurately measured using the simulated dental model of patient, so as to predict the teeth moving type, and improve teeth treatment plan on this basis. The extra-oral measuring technique of orthodontic force provides an important reference for clinical orthodontic treatment, and creates a novel idea for the optimal design of orthodontic plan.

Impact of the First Archwires Placement on the Everyday Activities of Orthodontics Patients / Impacto de la Instalación de los Primeros Arcos en las Actividades de Vida Diaria en Pacientes de Ortodoncia

ABSTRACT: Orthodontic treatment (OT) is essential for the aesthetic and functional rehabilitation of the chewing apparatus, however it may lead to certain complications which can have a negative impact on patients' everyday lives. The study included patients of the Dental Teaching Clinic of Universidad de La Frontera who were undergoing OT for the first time, with the placement of their first orthodontic arch. To analyse the impact of the placement of the first arches on everyday activities (EDA), patients completed a questionnaire with questions relating to their oral condition, including: functional limitation, physical impairment, psychological malaise, physical pain and oral hygiene. The impact on EDAs was classified as high, moderate or low. The chisquared test, Student's t-test and Spearman's coefficient were applied, using a significance threshold of 5 %. Statistical analysis used the SPSS software, v. 22.0. The variables were analysed by sex and age-band. Difficulty in brushing their teeth, eating and speaking were the limitations on EDAs most frequently reported by the patients. Females presented higher scores than males (p=0.003), showing that they suffer a greater negative impact on EDAs than do males. The majority of the patients presented a low impact on EDAs after the placement of their first orthodontic arches. Physical pain after installation, and difficulty in adapting to the orthodontic apparatus were factors determining a negative impact on EDAs, affecting sleep, speech, eating and oral hygiene of patients after starting OT.

RESUMEN: El tratamiento ortodóntico (TO) es esencial para la rehabilitación estética y funcional del aparato masticatorio, sin embargo puede determinar algunas complicaciones que pueden impactar negativamente en la vida diaria de los pacientes. Fueron incluidos pacientes de la Clínica Odontológica Docente Asistencial de la Universidad de La Frontera que realizaban tratamiento ortodóntico por primera vez, con instalación del primer arco ortodóntico. Para análisis del impacto de la instalación de los primeros arcos en las actividades de vida diaria (AVD), los pacientes llenaron un cuestionario con preguntas relacionadas a su condición oral, incluyendo: limitación funcional, incapacidad física, incapacidad psicológica, dolor físico e higiene oral. El impacto en las AVDs fueclasificado como alto, moderado y bajo. Para análisis estadístico se utilizó el software SPSS v. 22.0. Fueron aplicadas las pruebas de chi-cuadrado, t-student y Spearman's coefficient, considerándose umbral de significación de 5 %. Para análisis estadístico se utilizó el software SPSS v. 22.0. Las variables fueron analizadas según sexos y rangos etarios. Dificultad para cepillar los dientes, para comer y hablar fueron las limitaciones en las AVDs más frecuentemente reportadas por los pacientes. Las mujeres presentaron mayores puntajes en relación a los hombres (p=0,003), lo que demostró que presentan mayor impacto negativo en las AVDs en relación a los hombres. La mayoría de los pacientes presentaron bajo impacto en las AVDs tras la instalación de los primeros arcos de ortodoncia. El dolor físico tras instalación y la dificultad en la adaptación con el aparato ortodóntico fueron factores que determinaron impacto negativo en las AVDs, afectando el sueño, el habla, la alimentación y la higiene oral de los pacientes que iniciaron el TO.

Experimental Research on Friction between Domestic Brackets and Archwires / 中国医科大学学报

Objective To study the friction between brackets and archwires and the influential factors. Methods To test the friction of six combinations of canine bracket and stainless steel archwire, and to calculate the critical contact angles for each combination. Results The friction maintains stability with slight changes when the contact angle is smaller than the critical contact angle. The friction increases linearly when the contact angle is larger than the critical contact angle. The friction of different combinations of bracket-archwire are different and the critical contact angles are also different. Conclusion The critical contact angle influences the friction between bracket and archwire significantly. The critical contact angle is relevant to both the structure of the bracket and the size of the archwire.

An efficacy comparison between pre-adjusted and Begg appliance on the dentofacial morphology in Angle class Ⅱ division 1 extraction cases treated by light archwire technique / 实用口腔医学杂志

Objective:To compare the effects between Begg and pre-adjusted appliance on dentofacial morphology in Angle class Ⅱ division 1 extraction cases treated by light archwire technique.Methods:28 cases with Angle class Ⅱ division 1 who needed maximum maxillary incisor retraction were divided into 2 groups (MBT pre-adjusted and Begg group) and treated by light archwire technique.4 first premolars were extracted in all patients.Lateral cephalometric films were analyzed before and after treatment.Results:The upper incisors were intruded (0.18 ± 0.32)mm and (0.77 ± 0.91) mm in pre-adjusted and Begg group respectively (P ＜ 0.05).The other differences of cephalometric analyses between 2 groups were not significant (P ＞ 0.05).Conclusion:The effects were almost same with pre-adjusted and Begg appliances in Angle class Ⅱ division 1 extraction cases treated by light archwire technique except for that the latter is better than the former in vertical control of maxillary anterior teeth.

Measurement Analysis of the Frictional Resistance Between Tandem Archwire and Different Self-ligating Brackets / 昆明医科大学学报

Objective To measure the dynamic and static frictional resistances between different self-ligating orthodontic brackets and different combination of tandem archwires.Methods On standard model the upper right quadrant Damon Q self-ligating brackets was pasted as team A,3M Smart clip self-ligating brackets as team B and Forestadent Quick 3.0 self-ligating brackets as team C respectively.Nickel-titanium archwires of 0.012 inch and 0.016 inch and two nickel-titanium archwires of 0.014 inch were applied to simulate sliding in the brackets and measure the friction changes in brackets and archwires,so as to explore the frictional resistance between different combination of the tandem archwires and different self-ligating brackets.Results When using the combination of two 0.014-inch nickel-titanium tandem archwires,the static frictional resistances was significantly different (P＜ 0.05):team A ＜team B ＜team C while the kinetic frictional resistance was also significantly different (P＜0.05):team A ＜team B ＜team C,When using the combination of 0.012-inch and 0.016-inch nickel-titanium tandem archwires,the static frictional resistances was significantly different (P＜0.05):team A＜team B＜team C,while the kinetic frictional resistance was also significantly different (P＜0.05):team A＜team B＜team C.Gonclusion There are different frictional resistance in different kind of self-ligating brackets and different combination of the tandem archwires.The combination of two 0.014-inch nickel-titanium tandem archwire applied to Forestadent Quick 3.0 self-ligating brackets has the biggest frictional resistance while the combination of 0.012-inch and 0.016-inch nickel-titanium tandem archwire applied to the Damon Q self-ligating brackets has the lowest frictional resistance,which enables the teeth to move at the fastest speed and facilitates the following use of the edgewires.

Caso clínico tratado con brackets autoligantes activos / Clinical case treated with an active self ligating appliance

Los brackets autoligantes han llegado para quedarse en la Ortodoncia actual. Sus beneficios en higiene, eficiencia, manejo del anclaje, expresión de la prescripción y rentabilidad por puntear algunas características, hacen que sean la elección de una gran parte de los Ortodoncistas clínicos. Los brackets auto-ligantes activos, buscan a través de su clip flexible, expresar la prescripción, sea ésta Roth, MBT, Andrews, CCO u otra. Es muy importante que el clínico conozca la aparatología, en su manejo y en su información, para estar seguro que lo que necesita para cada paciente en particular puede ser logrado con ella. Es fundamental que la prescripción adecuada, esté inscripta en el bracket indicado, muchas veces con fines comerciales ese binomio puede no funcionar de la mejor forma.

Self-ligating brackets have arrived to stay in actual Orthodontics. Its benefits, such as hygiene, efficiency, anchorage management, prescription expression and profitability, are some of the reasons why clinical orthodontists around the world have chosen them. Active self ligating brackets, with the performance of its active and flexible clip, look for the total expression of the selected prescription, regardless of this being Roth, MBT, Andrews, CCO or some other. It is very important for the clinician to know the selected appliance in perfection, not only its handling but also its prescription. This is the only way to ensure that the selected appliance will be the best option for some specific patient. It is mandatory that the indicated prescription be installed in the correct appliance. Sometimes commercial outcomes may not have the best results.

‘Loops in Orthodontics’—A Review

Extraction space closure is an integral part of orthodontic treatment which demands a thorough understanding of the biomechanics. In the pre-adjusted edgewise technique, retraction is achieved either with friction (sliding) or frictionless mechanics. In the former, the wire and position of the bracket are important factors in tooth movement but the simplicity of friction mechanics is offset by the binding between bracket and archwire. This slows tooth movement, compromises the delivery of desired force levels, causes anchor loss and may be associated with undesirable side effect such as uncontrolled tipping and deep bite. A review of frictionless mechanics in general and most commonly used loops in retraction has been highlighted in this article.

Ortodontia lingual: arco reto ou arco em forma de cogumelo? / Lingual Orthodontics: straight-wire or mushroom archwire?

A Ortodontial lingual aplica dois tipos de arco com mais frequência em sua técnica. Foi introduzido mais recentemente o arco reto lingual, depois de décadas utilizando o arco em forma de cogumelo. Alguns autores defendem o uso do arco reto por terem diversas vantagens em relação ao arco cogumelo. Porém, outros ainda persistem com o arco cogumelo como uma escolha ideal para a ortodontia lingual. Esse trabalho teve como objetivo levantar comparativamente e discutir algumas vantagens e desvantagens de ambas formas de arco. Pode-se concluir que há vantagens e desvantagens em cada tipo; o arco reto pode ser uma boa opção para o ortodontista que necessita facilitações práticas para exercer a técnica e o arco em forma de cogumelo pode ser mais confortável. O arco reto pode ser uma melhor opção quando se deseja melhor controle de torque na região anterior; o arco em forma de cogumelo pode ser uma melhor opção quando se deseja alinhamentos; e os procedimentos laboratoriais para a adoção do arco reto podem ser mais trabalhosos que o arco em forma de cogumelo.

There are two archwires commonly used for lingual orthodontics. The lingual straight-wire was recently introduced after decades using the mushroom archwire. Some authors defend the use of the straight-wire affirming it has several advantages over the mushroom archwire. However, several authors still persist with the mushroom archwire as an ideal choice for lingual orthodontics technique. This study aimed to discuss the advantages and disadvantages of both archwire types establishing a comparison between both of them. It was concluded that each one of them have its advantages and disadvantages. Straigh-wire can be a good option when a more precise control of torque in the anterior region is required. In the other hand the mushroom archwire can be more comfortable, and it can also be a better option when aiming to obtain alignments. Regarding the laboratory procedures the adoption of the straight-wire can be more laborious than the mushroom archwire.

Evaluation of the lower incisor inclination during alignment and leveling using superelastic NiTi archwires: a laboratory study

OBJECTIVE: The aim of this laboratory study is to evaluate the influence of the shape and the length limitation of superelastic nickel-titanium (NiTi) archwires on lower incisors inclination during alignment and leveling. METHODS: Metal teeth mounted on a typodont articulator device were used to simulate a malocclusion of the mandibular arch (-3.5 mm model discrepancy). Three different shapes (Standard, Accuform and Ideal) of superelastic NiTi archwires (Sentalloy, GAC, USA) were tested. Specimens were divided in two groups: Group I, with no limitation of the archwire length; and Group II, with distal limitation. Each group had thirty specimens divided into three subgroups differentiated by the archwire shape. All groups used round wires with diameters of 0.014-in, 0.016-in, 0.018-in and 0.020-in. The recording of all intervals was accomplished using standardized digital photographs with orthogonal norm in relation to median sagittal plane. The buccolingual inclination of the incisor was registered using photographs and software CorelDraw. RESULTS: The results were obtained using ANOVA and Tukey's test at a significant level of 5%. The inclination of the lower incisor increased in both groups and subgroups. The shape of the archwire had statistically significant influence only in Group I - Standard (11.76º), Ideal (5.88º) and Accuform (1.93º). Analyzing the influence of the length limitation, despite the mean incisor tipping in Group II (3.91º) had been smaller than Group I (6.52º), no statistically significant difference was found, except for Standard, 3.89º with limitation and 11.76º without limitation. The greatest incisor tipping occurred with the 0.014-in archwires.

The comparison of the frictional force by the type and angle of orthodontic bracket and the coated or non-coated feature of archwire / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to evaluate the difference in frictional resistance among metal, ceramic, self-ligation brackets and coated or non-coated Ni-Ti archwires at various bracket-archwire angulations during the sliding movement of an orthodontic archwire, using an orthodontic sliding simulation device. METHODS: Four types of bracket (Micro-arch Perpect Clear2 Clippy-C and Damon3 and 5 types of orthodontic archwire (0.014", 0.016", and 0.016" x 0.022" inch coated Ni-Ti, and 0.016" and 0.016" x 0.022" inch Ni-Ti) were used. Further, the bracket-archwire angles were set at 4 different angulations: 0degrees, 3degrees, 6degrees, and 9degrees. RESULTS: The frictions from all the experimental groups were found to be significantly increased in order of self-ligation brackets, Micro-arch and Perpect Clear2 (p < 0.001). The presence of a coat had no effect on the friction of the same sized archwires at 0degrees and 3degrees bracket-archwire angles (p < 0.001). Coated archwires had significantly higher frictions than the same sized non-coated archwires at 6degrees and 9degrees bracket-archwire angles (p < 0.001). The frictions increased significantly as the bracket-archwire angles were increased (p < 0.001). CONCLUSIONS: The use of self-ligation brackets will be beneficial in clinical situations where a low frictional force is required. Further, in cases where crowding is not severe, the use of coated archwires should not cause problems. However, more additional explanation is required considering the fact that the damage of coated archwire and exposure of the metal portion in case of binding and notching and the effects of saliva were not taken into account.

Estudo fotoelástico do controle vertical com o arco de dupla chave na técnica Straight wire / Photoelastic study of the vertical control with double key loop archwire in the Straight wire technique

INTRODUÇÃO: em alguns casos, a extração de pré-molares torna-se necessária e nem sempre os espaços são completamente fechados após o alinhamento e nivelamento. O arco de dupla chave, ou Double Key Loop (DKL), é um arco retangular de aço para retração, com duas alças - uma mesial e outra distal ao canino. OBJETIVOS: este trabalho propôs-se a estudar o local onde a força é exercida, após a ativação desse arco, utilizando ativação na alça distal, ativação entre as alças e na alça distal, e ativação com Gurin®. MÉTODOS: foram montados nove modelos fotoelásticos de um arco dentário inferior, sem os primeiros pré-molares e os terceiros molares, com braquetes In-Ovation e arco DKL. O arco foi ativado e a região de incisivos, caninos e dentes posteriores foi fotografada, com interposição de filtros polarizadores de luz. RESULTADOS E CONCLUSÕES: após a análise do modelo fotoelástico, concluiu-se que a ativação com Gurin® pode produzir movimento de retração anterior com componente extrusivo; a ativação na alça distal pode produzir movimento de retração anterior sem componente extrusivo; e a ativação entre as alças e na alça distal pode produzir movimento de retração anterior com componente intrusivo.

INTRODUCTION: There are clinical situations in which the extraction of bicuspids becomes necessary and, eventually, the extraction spaces are completely closed after aligning and leveling the teeth. The Double Key Loop (DKL) is a stainless steel arch for retraction, with two loops (keys), one mesial and another distal to the canine. AIM: This study aims to study the area where the force is exerted after the activation of the distal loop, the activation of the loops among themselves and the distal loop, and the activation with Gurin®. METHODS: Nine photoelastic models of the inferior arch were made, without the first bicuspids and the third molars, with In-Ovation brackets and the DKL. With the interposition of polarizing filters, pictures of incisors canines and posterior teeth were taken, after the activation of the arch. RESULTS AND CONCLUSIONS: Based on the analysis of the photoelastic model, we concluded that the activation in the distal loop can produce an anterior retraction movement without an extrusive component, while the activation with Gurin® produces an extrusive component; besides that, the activation of the keys among themselves and the distal loop activation can produce an anterior retraction movement with an intrusive component.

Comparison of frictional forces between orthodontic brackets and archwires / 대한치과교정학회지

The object of this study was to evaluate how friction that occurs during the sliding movement of an orthodontic archwire through orthodontic brackets is differently affected by variant designs and ingredients of brackets and archwires and bracket-archwire angles. In order to simulate the situations which could occur during orthodontic treatment with fixed appliances, 4 types of brackets (Gemini(R), a stainless steel twin bracket; Mini Uni-Twin(R), a stainless steel bracket with a single bracket design and narrow mesio-distal width; Clarity(R), a metal-reinforced ceramic bracket; Transcend(R), a ceramic bracket) and 3 types of orthodontic archwires (0.016", 0.016 x 0.022" stainless steel, 0.016" Nitinol) were used and the bracket-archwire angles were controlled as 0 degrees, 3 degrees, 6 degrees, and 9 degrees, Gemini(R) significantly showed the lowest static and kinetic frictions (P < 0.001). Clarity showed the highest static and kinetic frictions with a bracket-archwire angle of 0 degrees, and Transcend at 6 degrees and 9 degrees (P < 0.001). An 0.016 x 0.022" stainless steel rectangular archwire significantly showed the highest static and kinetic frictions (P < 0.01). The lowest static and kinetic frictions were observed when the bracket-archwire angles were 0 degrees and 3 degrees with 0.016" stainless steel round archwires (P < 0.01), and 6 degrees and 9 degrees with 0.016 Nitinol (P < 0.001). The static and kinetic frictions were increased as the bracket-archwire angles were increased (P < 0.001).

Three dimensional photoelastic study on the initial stress distributions of alveolar bone when retracted by lingual K-loop archwire / 대한치과교정학회지

This study was designed to investigate the stress distribution of alveolar bone in case of en masse retraction with lingual K-loop archwire using the 3-dimensional photoelastic stress analysis followed by stress freezing process. Lingual K-loop archwire which had loop in 15mm height was used and activated by retraction force of 350gm per each side. The results were as follows: 1. Central incisor: As the closer side to crown, the larger tensile stress was distributed at both mesial and labial surfaces and the larger compressive stress was distributed at distal surface. As the closer side to root apex, the larger compressive stress was distributed at lingual surface. The compressive stress was distributed at root apex. 2. Lateral incisor: The tensile stress was distributed at the coronal side of mesial surface. The compressive stress was distributed at distal surface. As the closer side to crown, the larger tensile stress was distributed at labial surface. The tensile stress was distributed at coronal side and the compressive stress was distributed at apical side of lingual surface. The compressive stress was distributed at root apex. 3. Canine: The tensile stress was distributed at coronal side and the compressive stress was distributed at apical side of mesial surface. The tensile stress was distributed at distal surface. As the closer side to crown, the larger tensile stress was distributed at both mesial and distal surfaces. The compressive stress was distributed at root apex. 4. Second premolar: The tensile stress was distributed at mesial surface. The compressive stress was distributed at coronal side and the tensile stress was distributed at apical side of distal surface. The compressive stress was distributed at coronal side of buccal surface. As the closer side to crown, the larger tensile stress was distributed at lingual surface. The compressive stress was distributed at root apex. 5. First molar: As the closer side to crown, the larger tensile stress was distributed at both mesial and distal surfaces. No stress was distributed at buccal surface and palatal root apex. As the closer side to crown, the larger tensile stress was distributed at both lingual surfaces. The compressive stress was distributed at buccal root apexes. 6. Second molar: The compressive stress was distributed at all root apexes. As the closer side to crown, the larger compressive stress was distributed at both mesial and lingual surfaces, and the larger tensile stress at both distal and buccal surfaces. Transverse bowing effect was observed in en-masse retraction with lingual K-loop archwire, however vertical bowing effect was not. Rather, reverse vertical bowing effect was developed.

An experimental study on dynamic frictional resistance between brackets and archwires under the wet condition / 实用口腔医学杂志

Objective:To study the dynamic frictional resistance in the buccal segment between preadjusted brackets coupled with different archwires,at different times under artificial saliva condition.Methods: The dynamic friction of different combinations of 4 kinds of preadjusted brackets and 4 archwires were tested simulating archwires sliding in the buccal segments at 4 different times(0,15,30,45 d)under artificial saliva condition by using Instron universal testing machine.Results: The dynamic frictional resistance of combinations of 3M MBT bracket and all archwires were the smallest.The combinations of 0.46 mm inch stainless steel round wire and all brackets produced significantly lower dynamic frictional resistance than that of other archwires.The 0.48 mm?0.64 mm inch stainless steel rectangular wire produced the highest dynamic frictional resistance combined with all preadjusted brackets.The dynamic frictional resistance of combinations of archwires and brackets were highest at the 15th day and smallest at the 30th day under artificial saliva condition.Conclusion: 0.46 mm stainless steel round wire produces the smallest dynamic frictional resistance combined with all preadjusted brackets.3M MBT brackets are more favorable to sliding mechanics compared with other brackets.As for time,the lowest dynamic frictional resistance exhibits at the 30th day under artificial saliva condition.

A comparative study of frictional forces according to orthodontic wires and ligation method under dry and wet conditions / 대한치과교정학회지

The purpose of this study was fourfold - to evaluate the general laws of friction applied to orthodontic conditions, to compare archwire materials under these controlled conditions, to compare ligation method, and to measure the effect of the artificial saliva on friction with these materials Three wire alloys (Cobalt-chromium, Nickel-titanium, Beta-titanium) in two size wires (.016", .016"x.022") were examined respect to the bracket (.018"x.025" standard), and two ligature material (stainless steel, elastomeric) in dry and wet conditions The results were as follows, 1. The order of frictional force against alloy materials was Co-Cr (lowest), Ni-Ti, and beta-Ti(highest) - with the exception of elastomeric ligation under wet conditions. 2. S.S. ligation gave rise to significantly greater friction than elastomeric ligation did. 3. Testing in the presence of saliva, rather than in dry conditions, decreased the frictional force for S.S. ligation with .016" Co-Cr, Ni-Ti,beta-Ti. but, increased the frictional force for S.S. ligation with .016"x .022" Co-Cr, Ni-Ti, beta-Ti. 4. .016"x.022 "wire generated more friction than .016" wire.