Study on quantitative analysis of bracket-induced nonlinear response of labio-cheek soft tissue during the orthodontic process / 生物医学工程学杂志

In the orthodontics process, intervention and sliding of an orthodontic bracket during the orthodontic process can arise large response of the labio-cheek soft tissue. Soft tissue damage and ulcers frequently happen at the early stage of orthodontic treatment. In the field of orthodontic medicine, qualitative analysis is always carried out through statistics of clinical cases, while quantitative explanation of bio-mechanical mechanism is lacking. For this purpose, finite element analysis of a three-dimensional labio-cheek-bracket-tooth model is conducted to quantify the bracket-induced mechanical response of the labio-cheek soft tissue, which involves complex coupling of contact nonlinearity, material nonlinearity and geometric nonlinearity. Firstly, based on the biological composition characteristics of labio-cheek, a second-order Ogden model is optimally selected to describe the adipose-like material of the labio-cheek soft tissue. Secondly, according to the characteristics of oral activity, a two-stage simulation model of bracket intervention and orthogonal sliding is established, and the key contact parameters are optimally set. Finally, the two-level analysis method of overall model and submodel is used to achieve efficient solution of high-precision strains in submodels based on the displacement boundary obtained from the overall model calculation. Calculation results with four typical tooth morphologies during orthodontic treatment show that: ① the maximum strain of soft tissue is distributed along the sharp edges of the bracket, consistent with the clinically observed profile of soft tissue deformation; ② the maximum strain of soft tissue is reduced as the teeth align, consistent with the clinical manifestation of common damage and ulcers at the beginning of orthodontic treatment and reduced patient discomfort at the end of treatment. The method in this paper can provide reference for relevant quantitative analysis studies in the field of orthodontic medical treatment at home and abroad, and further benefit to the product development analysis of new orthodontic devices.

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.

Comparison of the High Cycle Fatigue Behavior of the Orthodontic NiTi Wires: An in Vitro Study

Abstract Objective: To compare the high-cycle fatigue behavior of four commercially available NiTi orthodontic wires. Material and Methods: Twelve NiTi orthodontic wires, round, 0.016-in, three per brand, were selected and divided into four groups: G1 - Heat-activated NiTi, G2 - Superelastic NiTi, G3 - Therma-Ti, and G4 - CopperNiTi. The atomic absorption spectrometry method was used to determine the chemical composition of investigated NiTi wires. We also performed a fatigue test at three-point bending using a universal testing machine for 1000 cycles in a 35 °C water bath. For the first and thousandth cycle, the average plateau load and the plateau length were determined in the unloading area of the force versus displacement diagram. In addition, we calculated the difference between the average plateau load of the first and thousandth cycle (∆F), as well as the difference between the plateau length of both cases (∆L). Results: According to our results, there were no significant differences between the average plateau load of the first and thousandth cycles of each group (p>0.05) and in the plateau length of the first and thousandth cycles of the groups (p>0.05). Conclusion: There were no significant differences between the groups changing the superelasticity property after high-cycle fatigue.

Caracterização mecânica, termodinâmica e química de fios CuNiTi ­ um estudo comparativo clínico e laboratorial / Mechanical, thermodynamic and chemical characterization of CuNiTi wires ­ a clinical and laboratory comparative study

Introdução: Os fios Copper Ni-Ti (CuNiTi) possuem indicações de uso clínico específicas, permanecendo no ambiente bucal por um longo período. Por esse motivo suas características mecânicas, termodinâmicas e estruturais devem ser preservadas durante todo o período de uso. Objetivos: Investigar se ocorrem alterações no comportamento mecânico, termodinâmico, estrutura e composição química superficial em fios CuNiTi 35°C submetidos ao envelhecimento in vivo (uso clínico) e in vitro (termociclagem), evidenciando as possíveis diferenças entre os métodos de envelhecimento. Material e Métodos: A amostra total foi constituída de 30 arcos pré-contornados 0.016", termodinâmicos com adição de cobre, e temperatura austenítica final (Af) de 35°C, da marca Ormco®. As análises destes fios resultaram em dois capítulos. Para o experimento clínico, 10 unidades de fios foram instaladas em 05 pacientes e permaneceram em meio bucal durante 30, 60 e 90 dias, e 05 fios foram analisados como recebidos (CR). A cada período, um hemiarco completo mais 1/3 (um terço) do hemiarco inferior direito foi retirado para análises. Para o experimento in vitro os 15 fios restantes foram submetidos à termociclagem para simulação do envelhecimento em ambiente oral durante 30 (600 ciclos), 60 (1200 ciclos) e 90 dias (1800 ciclos) com variação de temperatura entre 5°C e 55°C, com banhos de 90 segundos em cada temperatura, e transição de 15 segundos entre os banhos. Após cada período de envelhecimento in vivo e in vitro, os fios foram submetidos a um teste de padronização das suas dimensões através da medição dos diâmetros com paquímetro, Microscopia Eletrônica de Varredura (MEV), Espectrometria por Raios X Fluorescentes (FRX), ensaios de tração uniaxial e ensaio de Varredura Diferencial de Calorimetria (DSC). Resultados: No capítulo 1 a comparação entre os fios CR e os envelhecidos revelou que não houve diferença significativa entre os diâmetros das amostras, das forças obtidas ou mesmo das temperaturas Af, independentemente do tempo de permanência em boca. Foram encontrados predominantemente Ni, Ti, Cu e Al nas amostras, além de outros elementos químicos em concentrações variadas. No capítulo 2 não houve diferença significativa entre os diâmetros das amostras, das forças obtidas ou mesmo das temperaturas Af entre as amostras, independentemente do tempo ou do método de envelhecimento. Conclusão: As análises laboratoriais dos fios envelhecidos in vivo e in vitro foram comparadas, evidenciando que as características mecânicas, termodinâmicas e químicas dos fios permanecem estáveis mesmo até 90 dias de uso clínico ou 1800 ciclos de termociclagem. O método de envelhecimento in vitro se mostra uma alternativa viável para a análise destes parâmetros, em substituição aos métodos in vivo (AU).

Introduction: Copper Ni-Ti wires (CuNiTi) have specific indications for clinical use, remaining in the oral environment for a long period. For this reason, their mechanical, thermodynamic and structural characteristics must be preserved throughout the period of use of these materials. Objectives: To investigate whether there are changes in the mechanical, thermodynamic, structure and surface chemical composition of CuNiTi 35°C wires subjected to in vivo aging (clinical use) and in vitro (thermocycling), highlighting the possible differences between the aging methods. Material and Methods: The total sample was obtained from 30 pre-contoured Ormco® 0.016 thermodynamic archwires with copper addition and austenitic final temperature (Af) of 35°C. The analysis of these archwires resulted in two articles. For the clinical experiment, 10 units of wires were installed in 05 patients and remained in the oral environment for 30, 60 and 90 days, and 05 wires were analyzed as received. At each period, a complete hemiarch plus 1/3 of the right lower hemiarch was removed for analysis. For the in vitro experiment, the 15 remaining wires underwent thermocycling to simulate the aging of the oral environment for 30 (600 cycles), 60 (1200 cycles) and 90 days (1800 cycles) with a temperature range between 5°C and 55°C, with 90 second baths at each temperature, and 15 second transition between baths. After each in vivo and in vitro aging period, the wires underwent to a standardization test of their dimensions, by defining the diameters with a caliper, Scanning Electron Microscopy (SEM), Fluorescent X-Ray Spectrometry (FRX), tests of Uniaxial traction and Differential Scanning Calorimetry (DSC) test. Results: In chapter 1, the comparison between CR and aged wires revealed that there was no significant difference between the sample diameters, the forces obtained or even the temperatures Af, regardless the time spent in the mouth. Predominantly Ni, Ti, Cu and Al were found in the samples, in addition to other chemical elements in different concentrations. In chapter 2 there was no significant difference between the diameters of the samples, the forces obtained or even the temperatures Af between the samples, regardless of time or aging method. Conclusion: The comparison of the laboratoral analyzes of the archwires aged in vivo and in vitro showed that the mechanical, thermodynamic and the surface chemical characteristics were stable, even up to 90 days of clinical use or 1800 thermocycling cycles. The in vitro aging method is a viable alternative for the analysis of these parameters, replacing the in vivo methods (AU).

Effectiveness of methods for cleaning arch wire: an in vitro study

The aim of this study was to evaluate various methods of removing bacterial and fungus biofilm, to simulate orthodontic arch wires cleaning before reinsertion in the patients appliance. Rectangular Nickel Titanium (NiTi), Stainless Steel (SS) and Titanium Molybdenum (TMA) wires were divided into five groups, then contaminated with strains of Streptococcus mutans and Candida albicas. Four segments of each group served as control and were not contaminated. Six cleanings methods were used to remove the biofilm: cotton roll and a chemical agent (chlorhexidine, sodium hypochlorite, 70% alcohol), cotton roll and water, steel woll and immersion on enzymatic detergent. There was a control group not decontaminated Then wires were placed in broth separately, and after an incubation period the optical density (OD) was measured, observing whether there was microbial growth. A wire segment of each subgroup of SS 3M® was taken to the Scanning Electron Microscope (SEM) for visualization of the treatment response. The results were submitted to one-way ANOVA test and Tukey post-test. With the exception of 70% alcohol, the disinfection means behaved similarly regardless the type of wire. Two percent Chlorhexidine and 1% Sodium Hypochlorite totally removed the microorganisms while other agents left a high microbial concentration. Chemical cleaning is necessary to remove biofilm in orthodontic wires; 1% Sodium Hypochlorite and 2% Chlorhexidine are good disinfectants for this purpose.

Separation of aligning and leveling stages to control mandibular incisor inclination: A randomized clinical trial

ABSTRACT Objective: To determine whether separating the alignment and leveling phases can reduce proclination of the mandibular incisors. Methods: Eligibility criteria included Class I subjects with an irregularity index of 3-5 mm, 3-4 mm curve-of-Spee (COS), and non-extraction treatment. Thirty adults were randomly allocated into two groups: (1) Control group was leveled and aligned simultaneously with flat archwires progressively to 0.016x0.022-in stainless-steel; (2) Experimental group was aligned first with 0.014-in-superelastic NiTi with mild accentuated COS, then leveled using 0.016x0.022-in beta-titanium accentuated COS archwires and gradually reduced the curve until flat. Mandibular incisor position and inclination were evaluated by cephalometric analysis. COS and irregularity index were evaluated in study models. Assessment was conducted twice after 0.016-in NiTi and after 0.016x0.022-in stainless-steel archwire placements. Dental changes from cephalograms and models were compared within group using paired t-test and between groups using independent t-test. Results: Control group: Round-wire-phase, mandibular incisors tipped labially (4.38° and 1 mm) with intrusion (-1.13 mm); Rectangular-wire-phase, mandibular incisors further intruded and proclined (-0.63 mm and 1.38°). Experimental group: During aligning with round accentuated COS archwires, mandibular incisors tipped very slightly labially (0.75° and 0.50 mm) with no significant intrusion; during leveling with rectangular archwires, incisors majorly intruded (1.75 mm) with slight proclination (1.81°). The experimental group had significant less incisor proclination (control: 5.76°, experimental: 2.56°) with more incisor intrusion (control: -1.75 mm, experimental: -2.13 mm). The COS in experimental group showed significant greater reduction (-2.88 mm) than that of the control group (-1.69 mm). Conclusion: In control group, mandibular incisor proclination was markedly observed in round archwires, with further proclination caused by rectangular archwires. In experimental group, minimal proclination was exhibited when accentuated COS round archwires were used for aligning. Leveling with rectangular archwires caused less proclination with more COS reduction.

RESUMO Objetivo: Avaliar se separar os estágios de alinhamento e nivelamento reduz a projeção dos incisivos inferiores. Métodos: Os critérios de inclusão foram indivíduos Classe I com índice de irregularidade de 3-5mm, Curva de Spee (CS) de 3-4mm e tratamento sem extrações. Trinta adultos foram alocados aleatoriamente em dois grupos: o Grupo Controle (1) foi simultaneamente alinhado e nivelado com arcos planos progressivamente até atingir o 0,016" x 0,022" de aço inoxidável; o Grupo Experimental (2) foi inicialmente alinhado com arcos superelásticos NiTi 0,014" com CS levemente aumentada, em seguida nivelado com arcos de beta-titânio 0,016" x 0,022" com CS acentuada, que foi gradualmente reduzida até ficar plana. A posição e inclinação dos incisivos inferiores foram avaliadas por meio de análise cefalométrica. A CS e o índice de irregularidade foram avaliados por meio de modelos de estudo. A avaliação foi realizada duas vezes, sendo após a inserção dos arcos NiTi 0,016" e dos arcos 0,016" x 0,022" de aço. As mudanças dentárias visualizadas nos cefalogramas e nos modelos foram comparadas dentro dos grupos utilizando teste t pareado e entre os grupos utilizando o teste t independente. Resultados: Grupo Controle: estágio de arco redondo: os incisivos inferiores se inclinaram vestibularmente (4.38° e 1 mm) e intruíram (-1,13mm); estágio de arco retangular: os incisivos inferiores intruíram e se projetaram adicionalmente (-0.63mm e 1,38°). Grupo Experimental: Durante o alinhamento com arcos redondos e CS acentuada, os incisivos inferiores se inclinaram levemente para vestibular (0,75° e 0,50mm), sem intrusão significativa; durante o nivelamento com arcos retangulares, os incisivos, em sua maioria, intruíram (1,75mm), com uma leve projeção (1,81°). O grupo experimental apresentou projeção dos incisivos significativamente menor (controle: 5,76°; experimental: 2,56°), com maior intrusão dos incisivos (controle: -1,75mm; experimental: -2,13mm). A CS no Grupo Experimental apresentou redução significativamente maior (-2,88 mm) do que no grupo controle (-1,69 mm). Conclusão: No Grupo Controle, foi observada de forma notória a projeção dos incisivos inferiores nos arcos redondos, com projeção adicional causada pelos arcos retangulares. No Grupo Experimental, foi observada uma projeção mínima quando foram utilizados arcos redondos com CS acentuada para alinhamento. O nivelamento com arcos retangulares causou menos projeção com maior redução da CS.

Can we expect similar behavior among CuNiTi 35°C wires?

ABSTRACT Objective: This paper aims to verify the thermodynamic, mechanical and chemical properties of CuNiTi 35ºC commercial wires. Methods: Forty pre-contoured copper-nickel-titanium thermodynamic 0.017 x 0.025-in archwires with an Af temperature of 35°C were used. Eight wires from five different manufacturers (American Orthodontics® [G1], Eurodonto® [G2], Morelli® [G3], Ormco® [G4] and Orthometric® [G5]) underwent cross-sectional dimension measurements, tensile tests, SEM-EDS and differential scanning calorimetry (DSC) tests. Parametric tests (One-way ANOVA and Tukey post-test) were used, with a significance level of 5%, and Pearson's correlation coefficient test was performed between the Af and chemical elements of the wires. All sample tests and statistical analyses were double-blinded. Results: All wires presented standard dimensions (0.017 x 0.025-in) and superelastic behavior, with mean plateau forces of: G1 = 36.49N; G2 = 27.34N; G3 = 19.24 N; G4 = 37.54 N; and G5 = 17.87N. The Af means were: G1 = 29.40°C, G2 = 29.13°C and G3 = 31.43°C, with p>0.05 relative to each other. G4 (32.77°C) and G5 (35.17°C) presented statistically significant differences between each other and among the other groups. All samples presented Ni, Ti, Cu and Al in different concentrations. Conclusions: The chemical concentration of the elements that compose the alloy significantly influenced the thermodynamic and mechanical properties.

RESUMO Objetivo: O presente artigo teve como objetivo verificar as propriedades termodinâmicas, mecânicas e químicas de fios CuNiTi 35°C comerciais. Métodos: Foram utilizados 40 arcos termodinâmicos pré-contornados de cobre-níquel-titânio de 0,017" x 0,025" e temperatura Af de 35°C. Oito fios de cinco fabricantes diferentes (American Orthodontics® [G1], Eurodonto® [G2], Morelli® [G3], Ormco® [G4] e Orthometric® [G5]) foram submetidos a medições de suas secções transversais, testes de tração, MEV-EDS e calorimetria diferencial (DSC). Foram utilizados testes paramétricos (One-way ANOVA e pós-teste de Tukey), com nível de significância de 5%, e foi realizado o teste do coeficiente de correlação de Pearson entre a temperatura Af e os elementos químicos dos fios. Todos os testes das amostras e análises estatísticas foram duplo-cegos. Resultados: Todos os fios apresentavam dimensões padronizadas (0,017" x 0,025") e comportamento superelástico, com forças médias de platô de G1 = 36,49 N; G2 = 27,34 N; G3 = 19,24 N; G4 = 37,54 N; e G5 = 17,87 N. As médias de Af foram: G1 = 29,40°C, G2 = 29,13°C e G3 = 31,43°C, com p> 0,05 entre si. G4 (32,77°C) e G5 (35,17°C) apresentaram diferenças estatisticamente significativas entre si e entre os demais grupos. Todas as amostras apresentaram Ni, Ti, Cu e Al em diferentes concentrações. Conclusões: A concentração química dos elementos que compõem a liga influenciou significativamente as propriedades termodinâmicas e mecânicas.

Effect of fluoride on mechanical properties of NiTi and CuNiTi orthodontic archwires: an in vitro study

ABSTRACT Introduction: After debonding, white spot may appear on the area below the bracket, which is the early clinical sign of carious lesion. There is increased caries risk underneath and adjacent to orthodontic bands and brackets, which call for maximum use of caries preventive procedures using various fluoride application methods. Objective: The aim of the study was to evaluate alterations in the mechanical properties (modulus of elasticity and yield strength) in loading and unloading phases for different orthodontic archwires (nickel-titanium [NiTi] and copper-nickel-titanium [CuNiTi]) when exposed routinely to fluoride prophylactic agents for a predetermined period of time. Methods: Preformed rectangular NiTi and CuNiTi wires were immersed in fluoride solution and artificial saliva (control) for 90 minutes at 37ºC. After immersion, specimens were tested using a 3-point bend test on a universal testing machine. Results: There is a significant reduction in the unloading yield strength when the NiTi and CuNiTi wires were exposed to APF gel. Conclusion: The result suggests that use of topical fluoride agents affect the mechanical properties of the wires, leading to increase in treatment duration. Fluoride prophylactic agents must be used with caution in patients undergoing orthodontic treatment. Injudicious use of these agents may cause corrosive effects on the orthodontic wire surfaces, with alteration in their mechanical properties.

RESUMO Introdução: Após a remoção dos braquetes, manchas brancas podem aparecer na área embaixo deles, as quais são o sinal clínico inicial da lesão cariosa. Existe um maior risco de cáries embaixo e ao redor das bandas e braquetes ortodônticos, o que exige a máxima utilização de procedimentos preventivos de cárie, usando diferentes métodos com aplicação de flúor. Objetivo: O objetivo do presente estudo foi avaliar alterações nas propriedades mecânicas (módulo de elasticidade e resistência ao escoamento), nas fases de carregamento e descarregamento de diferentes fios ortodônticos (níquel-titânio [NiTi] e níquel-titânio com adição de cobre [CuNiTi]), quando expostos rotineiramente a agentes profiláticos fluoretados, utilizados durante um período de tempo predeterminado. Métodos: Os fios pré-contornados retangulares de NiTi e CuNiTi foram imersos em solução fluoretada e saliva artificial (controle) durante 90 minutos a 37°C. Após a imersão, as amostras foram testadas utilizando-se um teste de flexão em três pontos, em uma máquina universal de testes. Resultados: Houve uma redução significativa na resistência ao escoamento na fase de descarregamento quando os fios de NiTi e CuNiTi foram expostos ao gel fluoretado. Conclusão: O resultado sugere que o uso tópico de agentes fluoretados afeta as propriedades mecânicas dos fios, levando a um aumento na duração do tratamento. Os agentes profiláticos fluoretados devem ser utilizados com cautela em pacientes submetidos a tratamento ortodôntico. O uso indiscriminado desses agentes pode causar efeitos corrosivos na superfície dos fios ortodônticos e consequente alteração das suas propriedades mecânicas.

3D technology to measure dental arches and create a template for lingual brackets technique

ABSTRACT Objective: This study aims at identifying anatomical dimensions of dental arches, based on landmarks currently used in the lingual orthodontic technique, and create an archwire form template to be used in orthodontic clinics. Methods: Maxillary and mandibular dental casts of 140 Caucasian individuals with natural and normal occlusion were digitized (3D), and the images were analyzed with Delcam Power ShapeTM 2010 software. The dental arch shapes and sizes were obtained from 14 landmarks selected on the lingual surface of the teeth. Points and segments defined by the software were used to create an archwire form template. Results: Various dental arch patterns were found for both maxilla and mandible. The smallest sizes were found in females, and the largest were found in male subjects. Six categories were defined for each gender, three for the maxilla and three for the mandible (Small, Medium and Large). A template was created with eighteen anatomic lingual archwire designs, nine for the maxilla and nine for the mandible, for both genders. Conclusions: Landmarks evaluated in this study showed dental arch differences between genders. This information enables making orthodontic lingual archwires that are more compatible with the anatomical forms and sizes of the maxilla and mandible. The findings also allowed the creation of a template for an anatomic lingual metallic archwire form to be used in the lingual technique.

RESUMO Objetivo: O presente estudo tem como objetivo encontrar as formas anatômicas e dimensões das arcadas dentárias com base em pontos de referência utilizados na técnica ortodôntica lingual, e criar um diagrama com um maior número de arcos metálicos para serem utilizados na clínica ortodôntica. Métodos: 140 modelos de indivíduos caucasianos com oclusão normal e natural foram digitalizados (3D) e as imagens, analisadas com o software Delcam Power ShapeTM 2010. A determinação das formas e tamanhos das arcadas dentárias foi obtida a partir de 14 pontos selecionados na superfície lingual dos dentes. Outros pontos e segmentos foram utilizados, com o auxílio do software, para definir um diagrama. Resultados: Foram encontrados diferentes tamanhos de arcadas dentárias linguais, tanto para a maxila quanto para a mandíbula. Os menores tamanhos foram os femininos, e os maiores, os masculinos. Definiram-se seis tamanhos para cada sexo, sendo três para a maxila e três para a mandíbula, nomeados como P, M e G. Foi criado um diagrama com dezoito desenhos de arcos linguais anatômicos, nove para a maxila e nove para a mandíbula, para ambos os sexos. Conclusões: A posição dos pontos de referência nesse estudo evidenciou diferenças entre os sexos, o que permitiu a criação de arcos mais compatíveis com as formas e dimensões anatômicas da maxila e mandíbula. A diferença entre os tamanhos das arcadas dentárias linguais possibilitou a criação de um diagrama com formas de arcos metálicos linguais anatômicos para serem utilizados na técnica lingual, para auxiliar o profissional a criar os seus próprios arcos.

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.

Comparative Analysis of Stiffness of Lingual Appliances: An in Vitro Study

ABSTRACT Objective: To analyze and compare the stiffness of different lingual appliances with different archwires. Material and Methods: The three-point bending test was used to analyze the stiffness of the lingual archwires for the different lingual systems: eBrace, Harmony, Incognito, and STb. The deflection load curve of each archwire was obtained to evaluate how the section, the material and the manufacturer affect the elasticity and stiffness characteristics of the wires. The comparison of the stiffness between different systems was carried out through a factor variance analysis with three factors (manufacturer, cross-section, and material), followed by the post-hoc Tuckey test. Results: An increase in the system's rigidity was reported as the wire section increases, regardless of the manufacturer. The stainless steel archwires have ever higher stiffness values than NiTi and TMA. The STb wires of CuNiTi material, by virtue of the characteristics of the thermal wires, have flatter and lower load-deflection curves than the NiTi wires of other manufacturers. Conclusion: Archwires section and material showed a significant influence on the stiffness of the lingual systems. Archwires of the same section and material but different manufacturers show different load-deflection curves of stiffness.

Método de extrusión dentaria unitaria con fines protésicos: caso clínico / Single tooth extrusion method for prosthetic purposes: a clinical case

La pérdida de estructura dentaria por debajo del margen gingival y de la cresta ósea alveolar, ya sea por caries, fracturas traumáticas, desgaste, reabsorción radicular o perforaciones iatrogénicas, dificulta el tratamiento protésico y requiere un abordaje multidisciplinario para conseguir resultados óptimos y estables a largo plazo. Se presenta el caso de una paciente adulta que acude a consulta con la pieza 2.3, que no permite una adecuada restauración protésica sin invadir el espacio biológico. Dentro del abanico de posibilidades terapéuticas se selecciona la extrusión dentaria unitaria guiada, para poder exponer un remanente dentario adecuado supragingival, y conseguir un adecuado efecto ferrule para la posterior rehabilitación protésica. La técnica presentada es eficaz, simple, cómoda, higiénica y útil en pacientes que no desean realizarse tratamiento de ortodoncia en ambas arcadas (AU)

Attractiveness of different esthetic orthodontic wires

ABSTRACT Objective: The aim of this study was to evaluate the attractiveness of different types of esthetic orthodontic wires by laypeople and dentists. Methods: Five different types of orthodontic wires were evaluated: three esthetic wires (Teflon-coated, epoxy resin-coated and rhodium-coated wires), and two metallic wires (stainless steel and NiTi), as control. Monocrystalline ceramic brackets were installed in the maxillary arch of a patient presenting good dental alignment. The five evaluated wires were attached to the orthodontic appliance with an esthetic silicone elastic and photographed. The photographs were evaluated by 163 individuals, 110 dentists and 53 laypeople. The data were statistically evaluated by two-way ANOVA and one-way ANOVA, followed by Tukey tests. Results: There was a statistically significant difference in the attractiveness among the wires evaluated; the most esthetic was the rhodium-coated wire, followed by the epoxy resin-coated wire and, finally, the Teflon-coated wire, with no significant difference from the stainless steel and NiTi control archwires. There was no significant difference between the groups of evaluators. Conclusion: The most attractive was the rhodium-coated wire, followed by the epoxy resin-coated wire and, finally, the least attractive wire was the Teflon-coated wire, without statistically significant difference to the stainless steel and NiTi wires, used as control.

RESUMO Objetivo: O objetivo do presente estudo foi avaliar a atratividade de diferentes tipos de fios ortodônticos estéticos, na opinião de leigos e dentistas. Métodos: Foram avaliados cinco tipos diferentes de fios ortodônticos: três fios estéticos (revestidos com teflon, revestidos com resina epóxi e revestidos com ródio) e dois fios metálicos (aço inoxidável e NiTi), como grupo controle. Braquetes de cerâmica monocristalina foram instalados na arcada superior de uma paciente com bom alinhamento dentário, e os cinco fios avaliados foram fixados ao aparelho ortodôntico com ligadura elástica estética de silicone e fotografados. As fotografias foram avaliadas por 163 indivíduos, sendo 110 dentistas e 53 leigos. Os dados foram avaliados estatisticamente pelos testes ANOVA a um e a dois critérios, seguidos pelo teste de Tukey. Resultados: Houve diferença estatisticamente significativa na atratividade entre os fios avaliados. O mais estético foi o fio revestido de ródio, seguido pelo fio revestido de resina epóxica e, finalmente, o fio revestido de teflon, sem diferença significativa entre os fios de aço inoxidável e os de NiTi. Não houve diferença significativa entre os grupos de avaliadores. Conclusão: O mais atraente foi o fio revestido de ródio, seguido pelo fio revestido de resina epóxica e, finalmente, o fio menos atraente foi o fio revestido de teflon, sem diferença estatisticamente significativa para os fios de aço inoxidável e os de NiTi, utilizados como controle.

Avaliação do grau de corrosão de fios ortodônticos submetidos a desafio de pH / Evaluation of the corrosion degree of orthodontic wires subjected to pH challenge

Introdução: a movimentação dentária requer a aplicação de um sistema de forças que é orientado com o uso de acessórios, incluindo fios ortodônticos. Existem diversos materiais e fabricantes disponíveis no mercado, por isso é importante que o profissional conheça a composição deste material, uma vez que estará em contato com a mucosa oral, podendo sofrer corrosão e liberação de íons metálicos. Objetivo: avaliar, in vitro, o grau de corrosão de duas ligas metálicas que compõem fios ortodônticos de três fabricantes diferentes, submetidos à ciclagem de pH. Metodologia: 60 corpos de prova foram confeccionados com dois tipos de ligas metálicas (NiTi e CrNiaço 302) produzidas por três fabricantes diferentes, divididos em 6 Grupos de Testes com 10 unidades cada. Os corpos-de-prova foram submetidos à ciclagem ácida de pH 4,3, diariamente, e mantidos em estufa a 37 ° C por 14 dias. A massa foi pesada antes e após a ciclagem, por meio de balança analítica de precisão. A avaliação das características visuais dos fios foi realizada por um único observador em lupa estereomicroscópica. Resultados: a ciclagem de pH dos fios ortodônticos não promoveu perda significativa de massa ou corrosão, apesar da análise das características visuais terem mudado após a ciclagem. Conclusão: com base nos resultados do protocolo experimental estabelecido no presente estudo, a análise do comportamento das ligas de aço NiTi e CrNi ­ 302 que compõem os fios ortodônticos, frente ao desafio ácido de pH 4,3, por duas semanas, concluiu-se que esses materiais não apresentaram perdas de massa, opacidade, brilho e lisura consideradas significativas. Outros estudos são recomendados para fornecer maiores esclarecimentos sobre o tema.

Introduction: the tooth movement requires the application of a force system that is guided with the use of accessories, including orthodontic wires. There are several materials and manufacturers available on the market, so it is important that the professional knows the composition of this material, since it will be in contact with the oral mucosa, and may suffer corrosion and release metal ions. Objective: to evaluate, in vitro, the degree of corrosion of two metal alloys that make up orthodontic wires from three different manufacturers, submitted to pH cycling. Methodology: 60 specimens were made from two types of metal alloys (NiTi and CrNi ­ steel 302) produced by three different manufacturers, divided into 6 Test Groups with 10 units each. The specimens were subjected to acid pH 4.3 cycling, daily, and kept in an oven at 37 ° C for 14 days. The mass was obtained before and after cycling, using a precision analytical balance. The evaluation of the visual characteristics of the wires was performed by a single observer using a stereomicroscopic loupe. Results: the pH cycling of orthodontic wires did not promote significant loss of mass or corrosion, despite the analysis of visual characteristics having changed after cycling. Conclusion: based on the results of the experimental protocol established in the present study, the analysis of the behavior of the NiTi and CrNi ­ 302 steel alloys that make up the orthodontic wires, facing the acid challenge of pH 4.3, for two weeks, it was concluded that these materials did not present loss of mass, opacity, brightness and smoothness considered significant. Other studies are recommended to provide further clarification on the topic.

Evaluation of zinc-oxide nanocoating on the characteristics and antibacterial behavior of nickel-titanium alloy

ABSTRACT Objective: To investigate the effect of ZnO nanocoating on mechanical properties of NiTi orthodontic wires and antibacterial activity. Methods: 0.016 x 0.022-in NiTi orthodontic wires were coated with ZnO nanoparticles using an electrochemical deposition method with three electrodes system in 0.1M Zn(NO3)2. Mechanical properties and frictional resistance of the coated wires were investigated using an universal testing machine. Antibacterial effect of ZnO coating was also investigated. Results: A stable adhered ZnO nanocoating on NiTi wires was obtained. The coated wires have a significant antibacterial activity against S. aureus, S. pyogens and E. coli, and a reduction of frictional forces by 34%. Conclusion: ZnO nanocoating may improve the antibacterial effects of NiTi wires and reduce the frictional resistance. Coating may be implanted in orthodontic practice for faster and safer treatment.

RESUMO Objetivos: Avaliar o efeito do nanorrevestimento de óxido de zinco (ZnO) sobre as propriedades mecânicas e propriedades antibacterianas de fios ortodônticos de NiTi. Métodos: Fios 0,016" x 0,022" de NiTi foram revestidos com nanopartículas de ZnO por meio de um método de deposição eletroquímica com um sistema de três eletrodos a 0,1M Zn(NO3)2. Uma máquina universal de testes foi utilizada para avaliar as propriedades mecânicas e a resistência friccional dos fios revestidos. Além disso, também foram analisadas as propriedades antibacterianas do revestimento de ZnO. Resultados: Obteve-se uma aderência estável das nanopartículas de ZnO sobre os fios NiTi. Os fios revestidos apresentaram atividade antibacteriana significativa contra S. aureus, S. pyogens e E. coli, e apresentaram uma redução de 34% na força de atrito. Conclusão: O revestimento com nanopartículas de óxido de zinco pode melhorar as propriedades antibacterianas e reduzir a resistência friccional dos fios de NiTi. Assim, o revestimento dos fios pode ser utilizado na Ortodontia visando tratamentos mais rápidos e seguros.

Secuencia de arcos para el alineado y nivelado / Archwire sequence for alignment and leveling

La secuencia de arcos en ortodoncia, sobre todo, durante el alineado y nivelado es un tema de gran interés. Para esta etapa se han sugerido fuerzas de 50 gf que no superan la presión hidrostática capilar y no producen reabsorción radicular. El Nitinol es la aleación indicada en sus distintas variantes. Las revisiones sistemáticas no han hallado ventaja de ninguna secuencia de arcos, incluso, equiparando arcos de acero con figuras con el Nitinol termoelástico. La selección de la secuencia de arcos para un paciente depende de las características de la maloclusión(AU)

The sequence of arches in orthodontics especially during alignment and leveling is a subject of great interest. For this stage 50 g forces that do not exceed the capillary hydrostatic pressure and do not produce root resorption have been suggested. Nitinol is the indicated alloy in its different variants. Systematic Reviews have found no advantage of any arch sequence even by matching steel arches with figures with thermoelastic Nitinol. The selection of arch sequence for a patient depends on the characteristics of malocclusion(AU)

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.

Análisis de flexión en alambres de níquel-titanio con y sin propiedades de transformación térmica / Bending analysis of nickel-titanium wires with and no thermal transformation properties

Objetivo: Evaluar el comportamiento de los alambres de aleación de níquel-titanio con y sin propiedades de transformación térmica en la relación carga/deflexión. Materiales y método: Para ello, 30 segmentos de alambres de níquel-titanio con calibre .014" y 30 mm de largo fueron cortados, conformando 10 segmentos de alambre Flexy NiTi de Orthometric®, 10 segmentos Flexy Copper NiTi termoactivado y 10 segmentos CuNiTi de OrmcoTM. Se usó una máquina universal de ensayos Instron® para analizar el comportamiento de carga y deflexión de los segmentos en una prueba de tres puntos, registrando las fuerzas alcanzadas en 0,5 mm: 1 mm, 2 mm y 4 mm de deflexión. Resultados: Hubo una diferencia estadísticamente significativa entre todos los alambres y entre todas las deflexiones, ya que el alambre Flexy Cooper NiTi presentó la menor carga entre todas las deflexiones analizadas. Conclusión: Se concluye que los alambres termoactivados alcanzan fuerzas más leves, lo que los hace más apropiados para alineaciones iniciales, las cuales requieren un mayor rango de deflexión(AU)