Does the initial surface roughness of different CuNiTi wires affect the frictional resistance?

Abstract This study aimed to assess and correlate initial surface roughness and frictional resistance of rectangular CuNiTi wires inserted in different self-ligating brackets. The sample consisted of 40 bracket-wire sets (rectangular CuNiTi wires of 0.017" x 0.025" and passive self-ligating brackets) divided into four groups (n=10): metallic self-ligating bracket and metallic CuNiTi wire (G1); metallic self-ligating bracket and rhodium-coated CuNiTi wire (G2); esthetic self-ligating bracket and metallic wire (G3); esthetic self-ligating bracket and rhodium-coated CuNiTi wire (G4). The initial surface roughness of the wires was examined with a Surfcorder roughness meter, model SE1700. Later, frictional resistance was assessed in an Instron 4411 universal testing machine at a speed of 5 mm/min, in an aqueous medium at 35°C. Microscopic analyses of surface morphology were performed with scanning electron microscopy, using an LEO 1430, with magnifications of 1000X. Generalized linear models were applied, considering the 2 x 2 factorial (bracket type x wire type), at a 5% significance level. Regardless of bracket type, the groups with esthetic wires presented higher initial surface roughness than the groups with metallic wires (p<0.05). There was no significant difference between the different bracket-wire sets for frictional resistance and no significant correlation between frictional resistance and initial surface roughness in the environment studied. It is concluded that esthetic wires presented higher initial surface roughness but did not interfere with the frictional resistance between brackets and wires.

Resumo O objetivo deste estudo foi avaliar e correlacionar a rugosidade superficial inicial e a resistência a fricção dos fios CuNiTi retangulares inseridos em diferentes bráquetes autoligados. A amostra foi composta por 40 conjuntos bráquetes-fios (fios retangulares CuNiTi de 0.017" x 0.025" e braquetes autoligados passivos), divididos em 4 grupos (n=10): bráquete autoligado metálico e fio CuNiti metálico (G1); braquete autoligado metálico e fio CuNiti com revestimento de rhodium (G2); bráquete autoligado estético e fio metálico (G3); bráquete autoligado estético e fio CuNiti com revestimento de rhodium (G4). A rugosidade superficial inicial do fio foi examinada com um rugosímetro Surfcorder modelo SE1700. Posteriormente, a resistência a fricção foi avaliada em uma máquina de ensaios universal Instron 4411, a uma velocidade de 5mm/min em meio aquoso à 35oC. Análises microscópicas da morfologia de superfície foram realizadas por microscopia eletrônica de varredura, utilizando um LEO 1430, com ampliações de 1000X. Foram aplicados modelos lineares generalizados, considerando o fatorial 2 x 2 (tipo de bráquete x tipo de fio), com o nível de significância de 5%. Independentemente do tipo de bráquete, os grupos com fios estéticos apresentaram maior rugosidade superficial inicial que os grupos com fios metálicos (p<0,05). Não houve diferença significativa entre os diferentes conjuntos bráquetes-fios quanto a resistência à fricção e não houve correlação significativa entre a resistência a fricção e a rugosidade superficial inicial no ambiente estudado. Conclui-se que os fios estéticos apresentaram maior rugosidade superficial inicial porém não interferiram na resistência a fricção entre os braquetes e os fios.

Comparison between Fixation with Smooth Kirschner Wire and Cannulated Screws in Displaced Fractures of the Lateral Humeral Condyle in Children / Comparação entre fixação de fio de Kirschner liso e de parafusos canulados em fraturas deslocadas do côndilo lateral do úmero em crianças

Abstract Objective To compare the use of cannulated screws and smooth Kirschner wires in terms of reducing the presence of exuberant callus and complications in pediatric displaced fractures of the lateral humeral condyle. Methods An analytical cross-sectional study of consecutive cases was conducted from May to October 2021 with 30 children with displaced external humeral condyle fractures. The functional results regarding pain and range of motion were stratified using the Dhillon grading system. Results A total of 19 patients underwent Kirschner wire fixation, and 11 underwent cannulated screw fixation. Closed fixation was performed in 14 cases (47%), and open fixation, in 16 (53%). Of the cases included, there was no loss to follow-up. Te sample was composed of 21 (70%) male patients, and the age ranged from 5 to 15 years, with a mean of 6.96 years. The most frequent cause of fracture was fall from height (50%), which was related to greater displacement on baseline radiographs. Complications that were not related to the reduction approach or the implant used were observed in 12 (40%) cases. Conclusion The present study shows no benefits in relation to the use of smooth pins or cannulated screws to reduce the presence of exuberant callus in the consolidation of the fracture. We see that the complications that arise are related to the severity of the injury, and benefits cannot be identified in the choice of one implant over another. We could see that the Weiss classification helps to define the behavior in favor of open or closed reduction without interfering in kindness of the smooth pin or the cannulated screw for fracture fixation.

Resumo Objetivo Comparar o uso de parafusos canulados e de fios de Kirschner lisos em termos da redução da presença de calo exuberante e de complicações em fraturas pediátricas deslocadas do côndilo lateral do úmero. Métodos Um estudo analítico transversal de casos consecutivos foi realizado de maio a outubro de 2021 com 30 crianças com fraturas deslocadas de côndilo umeral externo. Os resultados funcionais para dor e amplitude de movimento foram estratificados utilizando o sistema de classificação Dhillon. Resultados Ao todo, 19 pacientes foram submetidos à fixação de fio Kirschner, e 11 à fixação de parafusos canulados. A fixação realizada foi fechada em 14 casos (47%) e aberta em 16 (53%). Dos casos incluídos, não houve perda no acompanhamento. A amostra continha 21 (70%) pacientes do sexo masculino, e a idade variou de 5 a 15 anos, com média de 6,96 anos. A causa mais frequente de fratura foi queda de altura (50%), e esteve relacionada ao maior deslocamento nas radiografias da linha de base. Complicações que não estavam relacionadas à abordagem de redução ou ao implante utilizado foram observadas em 12 (40%) casos. Conclusão Este estudo não mostra benefícios em relação ao uso de pinos lisos ou de parafusos canulados para reduzir a presença de calo exuberante na consolidação da fratura. Vemos que as complicações que surgem estão relacionadas à gravidade da lesão, e não é possível identificar benefícios na escolha de um implante ou outro. Pudemos ver que a classificação de Weiss ajuda a definir o comportamento em favor da redução aberta ou fechada sem dar preferência ao pino liso ou ao parafuso canulado para a fixação da fratura.

SURGICAL OUTCOME OF PERCUTANEOUS PIN FIXATION OF PROXIMAL THIRD FRACTURE OF ULNA IN MONTEGGIA FRACTURE DISLOCATION IN CHILDREN

Introduction: Monteggia fracture dislocation is a rare and severe injury of both paediatric and adult forearm and elbow.It was described for the first time by GIOVANNI BATTISTA MONTEGGIA in 1840,who reported two cases of fracture of the proximal third of ulna with conjoint ventral dislocation of the proximal radius. In 1967 JOSE LUIS BADO published a classification scheme of monteggia lesion based on the direction of the dislocation of radial head,this anatomical classification was suitable for both adults and children .Monteggia fracture dislocations constitute about 1% – 2% of all forearm fractures . Monteggia fractures remain challenging paediatric injuries because of difficulties in diagnosis , propensity for instability and complexity of late reconstruction. More than 50% of these fracture dislocation are misdiagnosed in children and leads to dysfunction of elbow joint. The fixation and stabilization of ulna fracture will automatically reduce the radial head dislocation. The aim of this study is to evaluate a group of paediatric patients with Monteggia lesion and its equivalents treated by percutaneous fixation of proximal third ulna fracture with k wire after reduction of fracture ulna and dislocated radio capitular joint under c-arm guidance. Materials and methods We treated 18 children of age ranging between 6 to 12 years with Monteggia fracture dislocation of the forearm with percutaneous fixation of the proximal third fracture of ulna with k wires after reduction of fracture and dislocated radio-capitular joint under C-arm control.The elbow is immobilized in fiexion with plaster of paris slab and bandage for a period of four weeks and mobilization of elbow is started after four weeks. By the end of 8 weeks K-wire removed. All fractures are fixed with in twenty four hours. The results Results : are good, there is no incidents of any stiffness. Range of movements of elbow and forearm are well preserved.The function of elbow and forearm are satisfactory.Conclusion:A good outcome after Monteggia injury in a child requires early diagnosis and prompt stable anatomical reduction of the ulna fracture and this can be achieved through stabilization of ulna by percutaneous intramedullary k wires.

Comparison of multistranded wire and fiber-reinforced composite retainers effects on periodontium: A randomized clinical trial

ABSTRACT Introduction: Fixed orthodontic retainers are very important for treatment stability; however, adverse effects on the health of periodontium can be caused as a result of deposition of plaque and calculus. Objectives: To compare and determine the effects of two mandibular fixed lingual retainers on the periodontal status, and to test the null hypothesis that there would be no significant difference on the periodontium health between the patients using fiber-reinforced composite (FRC) or multistranded wire (MSW) fixed retainers. Methods: A total of 60 subjects were recruited, out of which 6 were excluded and 2 dropped out during the study. Hence, 52 subjects with mean age of 21.5 ± 3.6 years were included in the study. The sample was composed by 8 males (15.4%) and 44 females (84.6%). The participants were randomly divided into two groups: Group 1 received fiber-reinforced composite retainer, while Group 2 received multistranded wire retainer. After insertion, plaque index, calculus index, gingival index and bleeding on probing were compared, after three months (T1), six months (T2), nine months (T3) and twelve months (T4), using Mann-Whitney test with p-value ≤ 0.05 as significant. Results: It could be seen that the health of periodontium deteriorated with the passage of time from T1 to T4 in both group of retainers. However, no statistically significant differences were found between the two groups (p> 0.05). Conclusion: The results of the study indicate that there was no significant difference on the health of periodontium between the patients with FRC and MSW fixed retainers, hence, the null hypothesis was accepted.

RESUMO Introdução: As contenções ortodônticas fixas são muito importantes para a estabilidade do tratamento; no entanto, elas podem causar efeitos adversos na saúde do periodonto, como resultado da deposição de placa e cálculo. Objetivos: Comparar e determinar os efeitos na saúde periodontal de duas contenções inferiores coladas por lingual, e testar a hipótese nula de que não haveria diferença significativa na saúde periodontal entre os pacientes usando contenções fixas de compósito reforçado com fibra (FRC) ou de fio multitrançado (MSW). Métodos: No total, 60 indivíduos foram recrutados, dos quais 6 foram excluídos e 2 desistiram durante o estudo. Assim, foram incluídos no estudo 52 indivíduos com média de idade de 21,5 ± 3,6 anos. A amostra foi composta por 8 homens (15,4%) e 44 mulheres (84,6%). Os participantes foram divididos aleatoriamente em dois grupos: O Grupo 1 recebeu contenção de compósito reforçado com fibra, enquanto o Grupo 2 recebeu contenção de fio multitrançado. Após três meses (T1), seis meses (T2), nove meses (T3) e doze meses (T4) da colagem, foram comparados os índices de placa e de cálculo, índice gengival e sangramento à sondagem, usando o teste de Mann-Whitney com p ≤ 0,05 como significativo. Resultados: Pôde-se observar que a saúde periodontal piorou com o passar do tempo, de T1 a T4, em ambos os grupos de contenções. No entanto, não foram encontradas diferenças estatisticamente significativas entre os dois grupos (p> 0,05). Conclusão: Os resultados do estudo indicam que não houve diferença significativa na saúde periodontal entre os pacientes com contenções fixas FRC e MSW; portanto, a hipótese nula foi aceita.

Deflection of tandem archwire in a specific self-ligating metal bracket system: an in vitro study

Abstract The aim of this study was to quantify the force exerted by tandem archwires in a specific system of passive self-ligating bracket. Forty-eight thermo-activated nickel-titanium orthodontic archwires were separated into four groups (n = 12): G1 - two .014" + .014" round archwires; G2 - two .014" + .016" round archwires; G3 - .014" x .025" rectangular archwire; and. G4 - .016" x .022" rectangular archwire. Brackets were fixed onto teeth 1.5 to 2.5 using a device that represented the upper teeth, maintaining an interbracket distance of 6.0 mm. The deflection tests were performed using the structure representative of tooth 1.1 as support on the Instron testing machine at a speed of 2.0 mm/min. The archwires were evaluated at deflections of 0.5 mm, 1.0 mm, and 1.5 mm. The data were analyzed by a generalized linear model, considering values at different deflections as repeated measurements in the same experimental unit (α = 0.5%). At 0.5 mm, higher forces were observed in G2 and G3, which did not differ significantly (p > 0.05). The lowest force was observed in G4 (p < 0.05). At 1.0 mm and 1.5 mm, the highest force was observed in G3, followed by G4 and G2 (p < 0.05). The lowest force was observed in G1 (p < 0.05). In general, tandem archwires (same or different calibers) in a specific passive self-ligating bracket exerted lower force when compared with rectangular archwires.

Metacarpal fractures treatment: comparasion between kirschner wire and intramedullary screw / Tratamento de fraturas metacarpais: comparação entre fios de kirschner e fixação intramedular

ABSTRACT Introduction: Metacarpal fractures are common and can be treated surgically using Kirschner wires (K-wires) or intramedullary fixation with compression screws (IMCS). Objectives: Analyze the postsurgical results from treating the metacarpal extra-articular fractures through the retrograde Kirschner wire technique, and compare it with the intramedullary compression screw fixation. Methods: Retrospective and quantitative studies were to analyze patients' medical records, and a postsurgical evaluation questionnaire was given to the patients, who were divided into K-wire and IMCS. Results: The period of immobilization with a splint took six weeks for the K-wire group and four weeks for the IMCS group. The average time for consolidation took, respectively, fifty-seven days and forty-seven days. The first group could restart their activities twenty-two days after the other, and the average force value of the treated hand, when compared with its contralateral, was 93.9% and 95.4%, respectively. Between the operated hand and its contralateral, there was a difference of 16° in the total measures of the metacarpophalangeal and interphalangeal joint's range of movement among the K-wire group and 5° among the IMCS group. Conclusion: The patients who participated in this study showed excellent results after surgery, and both treatments were proven to be safe and reliable. Evidence level III; Retrospective comparative study .

RESUMO Introdução: Fraturas dos metacarpos são frequentes e podem ser tratadas de forma cirúrgica com os fios de Kirschner (FK) e Fixação Intramedular com Parafuso de Compressão (FIPC). Objetivo: Analisar os resultados pós-operatórios do tratamento das fraturas extra-articulares dos metacarpos pela técnica retrógrada com fios de Kirschner e comparar com a fixação intramedular utilizando parafuso de compressão. Métodos: Estudo retrospectivo, quantitativo, com análise de prontuários, utilizando questionários de avaliação pós-operatória em dez pacientes divididos em dois grupos: FIPC e FK. Resultados: O período de imobilização com tala nos grupos FK e FIPC foram de seis e quatro semanas respectivamente, já o tempo médio para consolidação foi de 57 e 47 dias respectivamente. O grupo FK retornou as atividades laborais após os FIPC. O valor médio de força na mão acometida comparada a contralateral foi de 93,9% no grupo FK, e no FIPC de 95,4%. Medidas da soma de amplitude de movimento das articulações metacarpofalangeanas e interfalangeanas no grupo FK obtiveram diferença média entre as mãos operada e a contralateral de 16°, já na FIPC observou-se 5°. Conclusão: Os pacientes estudados apresentaram excelentes resultados pós-operatórios e ambos os tratamentos provam ser seguros e confiáveis. Nível de evidência III; Estudo retrospectivo comparativo .

Principios de fijación mediante Kirschner en las fracturas supracondíleas de húmero en el niño

Introducción: Las fracturas supracondíleas de húmero en el niño son lesiones frecuentes. El tratamiento de estas lesiones por lo general es de tipo quirúrgico mediante la reducción cerrada o abierta y colocación de alambres de Kirschner. Objetivo: Actualizar y brindar información sobre la fijación con alambres de Kirschner en pacientes pediátricos con fracturas supracondíleas de húmero. Métodos: La búsqueda y análisis de la información se realizó en un periodo de 61 días (primero de septiembre al 31 de octubre de 2022) y se emplearon las siguientes palabras: pediatric supracondylar humeral fractures AND pinning, pinning configuration, pinning loosening AND pediatric supracondylar fractures. Para centrar la búsqueda se utilizaron los operadores boléanos OR o AND según correspondía. A partir de la información obtenida se realizó una revisión bibliográfica de un total de 211 artículos publicados en las bases de datos PubMed, Hinari, SciELO y Medline mediante el gestor de búsqueda y administrador de referencias EndNote. De ellos se utilizaron 38 citas seleccionadas para realizar la revisión, todas de los últimos cinco años. Resultados: Se hace referencia a los tipos de alambre de Kirschner empleados para la fijación de este tipo de fracturas. Se mencionan las configuraciones de alambres más utilizados, como la de dos alambres laterales seguidos de la fijación cruzada. Se exponen los errores más frecuentes en la colocación de los alambres, además de las complicaciones relacionadas con este procedimiento quirúrgico. Conclusiones: Las fracturas supracondíleas del húmero en niños son en general de manejo quirúrgico. La reducción cerrada y osteosíntesis mediante la colocación de alambres de Kirschner percutáneos requiere de conocimientos técnicos específicos.

Introduction: Supracondylar humeral fractures in children are frequent injuries. The treatment of these injuries is generally a surgical one through closed or open reduction and placement of Kirschner wires. Objective: To update and provide information on Kirschner wire fixation in pediatric patients with supracondylar humeral fractures. Methods: The search and analysis of the information was carried out in a period of 61 days (September 1st to October 31st, 2022) and the following words were used: pediatric supracondylar humeral fractures AND pinning, pinning configuration, pinning loosening AND pediatric supracondylar fractures. To focus the search, the Boolean OR or AND operators were used as appropriate. Based on the information obtained, a bibliographic review of a total of 211 articles published in the PubMed, Hinari, SciELO and Medline databases was carried out using the search reference manager EndNote. Of which 38 selected citations were used to conduct the review, all from the last five years. Results: References are made to the types of Kirschner wire used for this kind of fracture fixation. The most widely used wire configurations are mentioned, such as two lateral wires followed by crossed fixation. The most frequent errors in the placement of the wires are exposed, in addition to the complications related to this surgical procedure. Conclusions: In general, supracondylar humeral fractures in children require surgical management. The closed reduction through the placement of percutaneous Kirschner wires, require specific technical knowledge.

Alignment efficiency and three-dimensional assessment of root resorption after alignment with conventional and copper-nickel-titanium archwires: A randomized controlled trial

ABSTRACT Objective: To compare alignment efficiency and root resorption between nickel-titanium (NiTi) and copper-nickel-titanium (CuNiTi) archwires after complete alignment in mandibular anterior region. Methods: In this two-arm parallel single-blind randomized controlled trial, forty-four patients with Class I malocclusion with mandibular anterior crowding were recruited form orthodontic clinic of All India Institute of Medical Sciences (Jodhpur, India). Patients were randomly allocated into NiTi and CuNiTi groups, with a 1:1 allocation. Alignment was performed using 0.014-in, 0.016-in, 0.018-in, 0.019x0.025-in archwire sequence in the respective groups, which terminated in 0.019 x 0.025-in stainless-steel working archwire. The primary outcome was alignment efficiency, measured on study models from baseline (T0) to the first, second, third, fourth and fifth-month (T5). Secondary outcome was root resorption, measured from CBCT scans taken at T0 and T5. Mixed-factorial ANOVA was used to compare Little's Irregularity Index (LII). For assessing the proportion of patients with complete alignment at the end of each month, Kaplan-Meier survival curve was built and time to treatment completion was compared between groups using log rank test. Paired t-test was used to assess external apical root resorption (EARR) within groups, whereas independent t-test was used to evaluate LII and EARR between the groups. Results: Twenty-two patients were recruited in each group. One patient was lost to follow-up in the CuNiTi group. No statistically significant differences were observed in alignment efficiency between the groups (p>0.05). Intergroup comparison revealed that the changes in root measurement in three-dimensions were not statistically significant (p>0.05), except for mandibular right central incisor, which showed increased resorption at root apex in NiTi group (p<0.01). Conclusion: The two alignment archwires showed similar rate of alignment at all time points. Root resorption measurement did not differ between the NiTi and CuNiTi groups, except for the mandibular right central incisor, which showed more resorption in NiTi group.

RESUMO Objetivo: Comparar os fios de níquel-titânio (NiTi) e de cobre-níquel-titânio (CuNiTi) quanto à eficiência do alinhamento e quantidade de reabsorção radicular, após alinhamento completo dos dentes da região anterior inferior. Métodos: Neste estudo clínico randomizado, cego, paralelo, de dois braços, quarenta e quatro pacientes com má oclusão Classe I e apinhamento anterior inferior foram recrutados na clínica ortodôntica do All India Institute of Medical Sciences (Jodhpur, India). Os pacientes foram alocados aleatoriamente nos grupos NiTi e CuNiTi, na proporção de 1:1. O alinhamento foi realizado usando a sequência de fios 0,014", 0,016", 0,018" e 0,019" x 0,025" nos respectivos grupos, finalizando com o arco de trabalho 0,019" x 0,025" de aço inoxidável. O desfecho primário foi a eficiência do alinhamento, medida nos modelos de estudo nos tempos inicial (T0) e após um, dois, três, quatro e cinco meses (T5). O desfecho secundário foi a reabsorção radicular, medida a partir de tomografias computadorizadas realizadas em T0 e T5. ANOVA fatorial mista foi utilizada para comparar o Índice de Irregularidade de Little (IIL). Para avaliar a proporção de pacientes com alinhamento completo ao fim de cada mês, foi construída uma curva de sobrevida pelo método de Kaplan-Meier, e o tempo até o fim do tratamento foi comparado entre os grupos por meio do teste log-rank. Um teste t pareado foi utilizado para avaliar a reabsorção radicular apical externa (RRAE) dentro dos grupos, enquanto um teste t independente foi utilizado para avaliar o IIL e a RRAE entre os grupos. Resultados: Vinte e dois pacientes foram recrutados em cada grupo. Um paciente perdeu o acompanhamento no grupo CuNiTi. Não foram observadas diferenças estatisticamente significativas entre os grupos quanto à eficiência do alinhamento (p>0,05). A comparação intergrupos revelou que as alterações na RRAE medida em três dimensões não foram estatisticamente significativas (p>0,05), exceto para o incisivo central inferior direito, que apresentou aumento da RRAE no grupo NiTi (p<0,01). Conclusão: Os dois tipos de fios de alinhamento apresentaram taxa de alinhamento semelhante em todos os momentos. A medida da reabsorção radicular não diferiu entre o grupo NiTi e CuNiTi, exceto para o incisivo central inferior direito, que apresentou maior reabsorção no grupo NiTi.

Características epidemiológicas de las fracturas supracondíleas de húmero en niños y adolescentes

Introducción: Las lesiones traumáticas del codo son muy frecuentes, sobre todo en niños y adolescentes. Algunas de ellas son de difícil tratamiento y se asocian a complicaciones. De ellas, las fracturas supracondíleas del húmero son una de las más frecuentes. Objetivo: Describir las características epidemiológicas de un grupo de pacientes con esta enfermedad traumática. Métodos: Se realizó un estudio observacional descriptivo en 56 pacientes menores de 18 años atendidos en el Hospital Pediátrico Provincial Dr. Eduardo Agramonte Piña de la provincia Camagüey desde el primero de enero de 2018 al 31 de diciembre de 2021 con un total de 48 meses. Resultados: La razón sexo masculino-femenino de los 56 pacientes fue de 3,3 a 1, codo izquierdo-derecho de 1,9 a 1 y zona rural urbana de 2,2 a 1. El promedio de edades en general fue de 7,5 años. La estadía hospitalaria promedio fue de 4,8 días. El mecanismo de extensión fue el hallazgo más frecuente, así como las fracturas grado III. Los meses de enero y julio en conjunto con los días del jueves, viernes y domingo son los que presentan la mayor cantidad de pacientes. La reducción cerrada y fijación percutánea con alambres de Kirschner fue el método más empleado en esta enfermedad traumática. Conclusiones: Las fracturas supracondíleas del humero en el niño son más frecuentes en el sexo masculino y el codo izquierdo. El promedio de edades en el sexo masculino es mayor que en el femenino. Las zonas rurales aportan la mayor cantidad de pacientes. El tratamiento más empleado es el quirúrgico y las complicaciones inmediatas son infrecuentes.

Introduction: Traumatic injuries of the elbow are very frequent, some of them are difficult to treat and are associated with complications, of which supracondylar fractures of the humerus are one of the most frequent. Objetive: To describe the epidemiological behavior of a group of patients with this traumatic disease. Methods: A descriptive observational study was carried out in patients treated at the Dr. Eduardo Agramonte Piña Provincial Pediatric Hospital in the city of Camagüey from January 1st, 2018 to December 31st, 2021 with a total of 48 months. Results: the male-female sex ratio of the 56 patients was 3.3 to 1, the left-right elbow was 1.9 to 1, and the urban rural area was 2.2 to 1. The average age in general was 7.5 years. The average hospital stay was 4.8 days. The extension mechanism was the most frequent finding, as well as grade III fractures. The months of January and July together with the days of Thursday, Friday and Sunday are the ones with the largest number of patients. Closed reduction and percutaneous fixation with Kirschner wires was the most used method in this traumatic entity. Conclusions: Supracondylar fractures of the humerus in children are more frequent in males and in the left elbow. The average age of males is higher than that of females. Rural areas provide the largest number of patients. The most used treatment is surgery and immediate complications are infrequent.

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.

Does ulna fixation alter the outcome for distal-third forearm fractures in children? / A fixação da ulna altera o desfecho das fraturas do terço distal do antebraço?

ABSTRACT Introduction Fractures of the distal third of the forearm are common in the pediatric population. Conservative treatment of an ipsilateral fracture of the distal ulna metaphysis is one of the risk factors for loss of reduction. Percutaneous fixation of the fracture with K-wires is recommended. This study aims to evaluate the outcome of percutaneous fixation of both bones performed as the primary treatment. Materials and Methods A randomized, open, prospective, clinical trial was conducted, including skeletally immature patients who underwent surgery for fractures of the distal radius and ulna. They were randomized into two groups, one with fixation only of the radius fracture and the other with fixation of both the radius and the ulna fractures, and they were followed clinically and radiologically for up to 12 weeks postoperatively. Results Sixteen children were selected. In the intraoperative period, fluoroscopy was activated for a longer time when fixing the ulna (p = 0.011) and the surgical time was longer in this group (p = 0.014). In the postoperative evaluations, the group whose surgery involved the fixation of both bones had a lower postoperative pain score (p <0.001) and less time away from school (p <0.001). Conclusions In this study, postoperative pain and absence from school were both less when fixation of the radius and ulna was performed. Evidence Level II; Randomized Controlled Study.

RESUMO Introdução As fraturas do terço distal do antebraço são comuns na população pediátrica. O tratamento conservador da fratura ipsilateral da metáfise distal da ulna é um dos fatores de risco para a perda da redução. Recomenda-se a fixação percutânea da fratura com fios K. Este estudo tem como objetivo avaliar o resultado da fixação percutânea de ambos os ossos realizada como tratamento primário. Materiais e Métodos Foi realizado um estudo clínico randomizado, aberto e prospectivo, que incluiu pacientes com esqueleto imaturo que foram submetidos à cirurgia para fraturas da parte distal do rádio e a ulna. Os participantes foram randomizados em dois grupos, um com fixação apenas da fratura do rádio e outro com fixação das fraturas do rádio e da ulna, e foram acompanhados clínica e radiologicamente por até 12 semanas de pós-operatório. Resultados Dezesseis crianças foram selecionadas. No intraoperatório, a fluoroscopia foi ativada por mais tempo na fixação da ulna (p = 0,011) e o tempo cirúrgico foi maior nesse grupo (p = 0,014). Nas avaliações pós-operatórias, o grupo cuja cirurgia envolveu a fixação de ambos os ossos teve escore de dor menor depois da cirurgia (p < 0,001) e menos tempo de afastamento da escola (p < 0,001). Conclusões Neste estudo, a dor pós-operatória e o afastamento da escola foram menores quando se realizou fixação do rádio e da ulna. Nível de Evidência II; Estudo randomizado controlado.

Application of extended trochanter osteotomy wire fixation combined with autologous bone graft in revision of total hip arthroplasty / 中国骨伤

OBJECTIVE@#To investigate the clinical effect of using lengthened trochanteric osteotomy wire fixation combined with autologous bone graft in patients undergoing revision total hip arthroplasty.@*METHODS@#From December 2010 to December 2018, 18 patients underwent revision of total hip arthroplasty with extended trochanteric osteotomy wire fixation and autogenous bone graft, including 8 males and 10 females with an average age of (78.89±3.32) years old ranging from 68 to 82 years. The time from the initial replacement to the revision was 9 to 22 (16.33±2.93) years. The patients were followed up regularly after operation. The healing time of osteotomy, the time of full weight-bearing activity, Harris score of hip joint and complications were recorded.@*RESULTS@#All 18 patients were followed up for 16 to 38 months with an average of (25.78±6.65) months. The incision length was 16 to 21 cm with an average of (18.89±1.32) cm; the operation time was 105 to 128 min with an average of (115.44±6.59) min, the bleeding volume was 240 to 285 ml with an average of (267.44±13.77) ml. The healing time of osteotomy was 12 to 18 weeks with an average of (15.61±1.75) weeks. Harris score of hip joint was (47.11±5.04) before operation, (76.39±3.85) during full weight-bearing activities, and (82.22±2.76) at the final follow-up(P<0.05). During the follow-up period, there were no complications such as limb shortening, infection, poor incision healing, prosthesis loosening and sinking, and periprosthetic fracture.@*CONCLUSION@#In revision total hip arthroplasty, the use of extended trochanteric osteotomy wire fixation combined with autologous bone graft can achieve satisfactory clinical results, but the surgeon needs to make a systematic plan for the pre-revision, intraoperative and postoperative recovery.

Treatment of trochanter fractures in total hip arthroplasty with ventral compression steel wire tension band / 中华骨科杂志

Objective:To evaluate the various wire tension belt ventral compression wiring technologiesfor treating several types of femoral greater trochanter fractures in total hip replacement, according to the different types of greater trochanter of femur fractures.Methods:From March 2013 to June 2019, a total of 1 280 cases of primary total hip arthroplasty were completed in our hospital, 21 patients with greater trochanter fractures were identified in total hip replacement. There were 11 males and 10 females with an average age of 65.81±6.45 years (range 42-76 years). All of them were unilateral. There were 11 cases on the left and 10 cases on the right. There were 11 cases of osteoarthritis secondary to hip dysplasia, 4 cases of hip osteoarthritis, 4 cases of aseptic necrosis of femoral head and 2 cases of femoral neck fracture. Different wire tension belt ventral compression wiring technologies were used for each fracture type. Harris hip function score, Parker activity score, and visual analogue scale (VAS) score of hip pain were evaluated during follow-up. X-ray films were taken to evaluate the fracture healing, prosthesis position, loosening and dislocation.Results:Three new fracture types were proposed: A transverse fracture from the greater trochanter tip to the base (4 cases); B oblique fracture from the greater trochanter tip to the base (according to the fracture line direction, type B was further divided into types B1 (4 cases) and B2 (6 cases); and C fracture line from the greater trochanter to subtrochanteric plane (7 cases). Among the 21 patients, one died at an early stage, two were lost during follow-up, and 18 were followed up for an average of 30.7±7.6 months. In 18 patients, the mean operation time was 110.0±20.0 min, and the mean intraoperative blood loss was 356.9±115.7 ml. The patients' Harris score was 35.26±5.52 at the preoperative, 65.7±6.42 at the 3 months after operation, and 87.75±6.21 at the final follow-up. The difference was statistically significant ( F=377.23, P<0.001). The patients' Parker score was 2.17±0.98 at the preoperative, 5.94±1.11 at the 3 months after operation,and 8.01±0.77 at the final follow-up. The difference was statistically significant ( F=170.96, P<0.001). The patients' VAS score was 6.22±1.11 at the preoperative, 2.61±0.92 at the 3 months after operation, and 1.28±0.67 at the final follow-up. The difference was statistically significant ( F=139.71, P<0.001). Deep vein embolism, heterotopic ossification was noted in one and another patient, respectively. The patient with non-union refused reoperation and had a broken steel wire, lower-limb limp, and no notable pain at the 12-month follow-up examination. Radiographs of 17 patients showed good location of the femoral prosthesis and no chronic pain. Conclusion:Different types of greater trochanter fractures in total hip arthroplasty were proposed, using different wire tension belt ventral compression wiring technologies for the various types of femoral greater trochanter fractures during total hip replacement can improve clinical outcomes.

The curative effect of modified double Kirschner wire compression fixation in the treatment of skeletal mallet fingers and its influencing factors / 中国医师进修杂志

Objective:To explore the curative effect of modified double Kirschner wire compression fixation in the treatment of skeletal mallet fingers, and analyze the related influencing factors of curative effect.Methods:The clinical data of 100 patients with skeletal mallet fingers from January 2018 to December 2020 in Yanzhou Branch of Affiliated Hospital of Jining Medical University were retrospectively analyzed, and the patients were treated with modified double Kirschner wire compression fixation. Before surgery and 8 weeks after surgery, the Fugl-Meyer score, simple test for evaluating hand function (STEF) score and visual analogue score (VAS) were assessed, and the flexion range of knuckles was measured. The curative effect was evaluated by Crawford standard, excellent and good means was good prognosis, medium and poor was poor prognosis. Binary Logistic regression was used to analyze the influencing factors of curative effect in patients with skeletal mallet fingers, Spearman method was used to analyze correlation.Results:All incisions healed in the first stage 14 d after surgery, the function and structure of the hand recovered well, and related incision skin necrosis and needle tract infection did not occur. Compared with before surgery, the Fugl-Meyer score, STEF score and flexion range of knuckles 8 weeks after surgery were significantly higher: (62.58 ± 4.56) scores vs. (32.33 ± 2.84) scores, (91.31 ± 3.19) scores vs. (62.51 ± 3.42) scores and (66.72 ± 3.65)° vs. (45.56 ± 2.31)°, the VAS was significantly lower: (2.65 ± 1.19) scores vs. (5.68 ± 1.43) scores, and there were statistical differences ( P<0.01). According to Crawford standard, good prognosis was in 79 cases, and poor prognosis was in 21 cases. There were no statistical differences in gender composition, injury location, cause of injury and type of injury between good prognosis patients and poor prognosis patients ( P>0.05); compared with the poor prognosis patients, the good prognosis patients were younger, the time from injury to surgery was shorter, the injured parts were mainly the little finger and ring finger, and there were statistical differences ( P<0.05 or <0.01). Binary Logistic regression analysis result showed that age, time from injury to operation and injury site were independent risk factors of curative effect in patients with skeletal mallet fingers ( OR = 4.62, 5.94 and 2.33; 95% CI 1.06 to 20.14, 2.23 to 15.81 and 1.12 to 4.82; P<0.05 or <0.01). Spearman correlation analysis result showed that the curative effect was positively correlated with age, time from injury to operation and injury location ( r = 0.25, 0.62 and 0.43; P<0.05 or <0.01). Conclusions:Modified double Kirschner wire compression fixation in the treatment of skeletal mallet fingers can promote the recovery of finger function after surgery, but age, damaged location and time of visit are independent risk factors of curative effect.

Evaluation of Lubrication Coatings for Intravascular Catheters, Wires, and Delivery System / 中国医疗器械杂志

Lubrication coating is widely used to reduce the friction between the interventional devices and the blood vessels, improves the surface biocompatibility of the interventional device, and also brings the coating stability problems and related risks. This paper describes the coating-related content from the equipment description, performance verification, technical requirements, etc., to reduce the risk of the coating to an acceptable level.

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).

Comparison of two methods of fixation of supracondylar fractures of the humerus in children / Comparação de dois métodos de fixação de fraturas supracondilianas do úmero em crianças

ABSTRACT Objective: To compare the outcomes of the fixation of complete and displaced supracondylar humeral fractures in children with two different Kirschner wire configurations. Methods: The type of fixation was randomized to either crossed (19 cases), or two divergent lateral Kirschner wires (24 cases). The comparison was made six months later between the two treated groups and each group with the non-fractured elbow (clinical alignment, range of motion, Baumann angle, and lateral humeral capitellar angle). Results: 43 children were evaluated (65% boys) with a mean age of six years and five months. The carrying angle (p = 0.94), extension (p = 0.89), and the Flynn´s criteria (p = 0.56) were similar between the groups. The flexion was slightly smaller for the crossed wire group (p = 0.04), but similar to the uninjured side. The Baumann angle was not different between the two fixations (p = 0.79) and the contralateral side (p = 0.1). The lateral humeral capitellar angle was slightly greater for the lateral pinning (p = 0.08), but with no difference with the uninjured elbow (p = 0.62). No iatrogenic injuries were observed. Conclusion: Both fixations presented similar outcomes that did not significantly affect the carrying angle in relation to the non-fractured side. Level of evidence II, Therapeutic study - Investigating the results of treatment.

RESUMO Objetivo: Comparar os resultados da fixação das fraturas supracondilianas completas e desviadas do úmero de crianças com dois tipos de configuração de fios de Kirschner. Método: O tipo de fixação foi aleatorizado para fixação com dois fios de Kirchner cruzados ou laterais divergentes. Depois de seis meses foi feita a comparação entre os dois grupos fixados entre si e cada um deles com o lado não fraturado do mesmo paciente (alinhamento clínico, arco de movimento, critérios de Flynn, ângulos de Baumann e capituloumeral). Resultados: Participaram do estudo 43 crianças (65% meninos), com idade média de seis anos e cinco meses. A extensão (p = 0,89), o ângulo de carregamento (p = 0,94) e os critérios de Flynn (p = 0,56) foram semelhantes entre os dois grupos, sem ocorrência de lesões iatrogênicas. A flexão foi discretamente menor no grupo com fios cruzados (p = 0,04), mas próximo do cotovelo normal. O ângulo de Baumann não apresentou diferença entre as duas fixações (p = 0,79), bem como com o lado não fraturado (p = 0,01). O ângulo capituloumeral foi ligeiramente maior (p = 0,08) nos fios laterais, mas sem diferença em relação lado normal (p = 0,62). Conclusão: As duas fixações apresentaram resultados similares e não alteraram significativamente o ângulo frontal do cotovelo em relação ao lado não fraturado. Nível de evidência II, Estudo terapêutico - Investigação dos resultados do tratamento.

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.

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.