RESUMEN

OBJECTIVE: The aim of this study is to assess the microbial contamination of three different brands of esthetic elastomeric ligatures. MATERIALS AND METHODS: Different brands of esthetic ligatures (Unistick Pearl [American Orthodontics, Sheboygan, WI, USA], Power Sticks Pearl [Ortho Technology, Tampa, FL, USA], and Ease [Obscure, 3M Unitek, Monrovia, CA, USA]) were randomly assigned to permanent canines of 25 patients (aged 11-18 years) undergoing corrective orthodontic treatment. After 30 days, the ligatures were removed, processed, and the biofilm composition was analyzed by checkerboard DNA-DNA hybridization for 40 bacterial species. The microbiological data were analyzed using a nonparametric mixed model. RESULTS: The ligatures presented intense microbial contamination after 30 days, but no statistically significant differences were observed among the three groups (p > 0.05). The levels of the evaluated individual species and proportions of the microbial complexes showed no statistically significant differences among the ligature groups (p > 0.05). CONCLUSIONS: Esthetic elastomeric ligatures became multicolonized by several bacterial species after 30 days of exposure to the oral cavity. However, no relevant differences were observed among the biofilm composition formed on the different ligature brands.

Asunto(s)

RESUMEN

In 2021, global plastics production was 390.7 Mt; in 2022, it was 400.3 Mt, showing an increase of 2.4%, and this rising tendency will increase yearly. Of this data, less than 2% correspond to bio-based plastics. Currently, polymers, including elastomers, are non-recyclable and come from non-renewable sources. Additionally, most elastomers are thermosets, making them complex to recycle and reuse. It takes hundreds to thousands of years to decompose or biodegrade, contributing to plastic waste accumulation, nano and microplastic formation, and environmental pollution. Due to this, the synthesis of elastomers from natural and renewable resources has attracted the attention of researchers and industries. In this review paper, new methods and strategies are proposed for the preparation of bio-based elastomers. The main goals are the advances and improvements in the synthesis, properties, and applications of bio-based elastomers from natural and industrial rubbers, polyurethanes, polyesters, and polyethers, and an approach to their circular economy and sustainability. Olefin metathesis is proposed as a novel and sustainable method for the synthesis of bio-based elastomers, which allows for the depolymerization or degradation of rubbers with the use of essential oils, terpenes, fatty acids, and fatty alcohols from natural resources such as chain transfer agents (CTA) or donors of the terminal groups in the main chain, which allow for control of the molecular weights and functional groups, obtaining new compounds, oligomers, and bio-based elastomers with an added value for the application of new polymers and materials. This tendency contributes to the development of bio-based elastomers that can reduce carbon emissions, avoid cross-contamination from fossil fuels, and obtain a greener material with biodegradable and/or compostable behavior.

Asunto(s)

RESUMEN

BACKGROUND: Elastomeric chains promote controlled movements and are widely used in orthodontics. OBJECTIVES: The aim of the study was to evaluate the force decay and elongation of orthodontic chains exposed to low-pH saliva (pH = 4) and different beverages common in the diet. MATERIAL AND METHODS: Force decay and elongation were determined in vitro at 6 time intervals over 21 days for 2 commercial elastomeric chains - Ormco (group A) and Borgatta (group B). The samples were immersed in artificial saliva (AS) at pH 4, Coca-Cola®, coffee, or beer for 15 min every day, or in AS (the control group). For the remaining time, the chains were placed into AS at 37°C. In addition, microscopic qualitative changes were recorded by means of scanning electron microscopy (SEM). RESULTS: The group B chains showed higher force decay and elongation at the end of the follow-up as compared to the group A chains. Exposure to beer had a greater impact on the force decay and elongation of the chains as compared to other liquids, but it was not statistically significant. The group A chains showed a more irregular surface than the group B chains, in particular, those exposed to coffee. CONCLUSIONS: Elastomeric chains suffer force decay and elongation as a function of time, mainly in the first 24 h. At the end of the follow-up, the group A chains exhibited less force decay in comparison with the group B chains. The qualitative observations showed that the chains in group A had a more irregular surface than the chains in group B.

Asunto(s)

RESUMEN

This paper presents the development and application of a multiplexed intensity variation-based sensor system for multiplane shape reconstruction. The sensor is based on a polymer optical fiber (POF) with sequential lateral sections coupled with a flexible light-emitting diode (LED) belt. The optical source modulation enables the development of 30 independent sensors using one photodetector, where the sensor system is embedded in polydimethylsiloxane (PDMS) resin in two configurations. Configuration 1 is a continuous PDMS layer applied in the interface between the flexible LED belt and the POF, whereas Configuration 2 comprises a 20 mm length PDMS layer only on each lateral section and LED region. The finite element method (FEM) is employed for the strain distribution evaluation in different conditions, including the strain distribution on the sensor system subjected to momentums in roll, pitch and yaw conditions. The experimental results of pressure application at 30 regions for each configuration indicated a higher sensitivity of Configuration 1 (83.58 a.u./kPa) when compared with Configuration 2 (40.06 a.u./kPa). However, Configuration 2 presented the smallest cross-sensitivity between sequential sensors (0.94 a.u./kPa against 45.5 a.u./kPa of Configuration 1). Then, the possibility of real-time loading condition monitoring and shape reconstruction is evaluated using Configuration 1 subjected to momentums in roll, pitch and yaw, as well as mechanical waves applied on the sensor structure. The strain distribution on the sensor presented the same pattern as the one obtained in the simulations, and the real-time response of each sensor was obtained for each case. In addition, the possibility of real-time loading condition estimation is analyzed using the k-means algorithm (an unsupervised machine learning approach) for the clusterization of data regarding the loading condition. The comparison between the predicted results and the real ones shows a 90.55% success rate. Thus, the proposed sensor device is a feasible alternative for integrated sensing in movement analysis, structural health monitoring submitted to dynamic loading and robotics for the assessment of the robot structure.

Asunto(s)

RESUMEN

Resumo Este trabalho avaliou a padronização da força inicial liberada por elásticos ortodônticos em cadeia em diferentes lotes de fabricação de três marcas comerciais. Foram testadas 762 amostras de elásticos em cadeia incolores, tamanho médio, das marcas Morelli®, Uniden® e Eurodonto®. Os elásticos foram distribuídos em 6 diferentes grupos: Grupo M (Morelli), Grupo U (Uniden) e Grupo E (Eurodonto), com 2 lotes para cada grupo. Os elásticos foram mantidos em um "jig" de acrílico de 07 X 07 cm que foi fixado em uma base de madeira de 55 X 15 cm. Os elásticos foram ativados em 50% de seus comprimentos iniciais e as forças iniciais liberadas foram mensuradas através de um dinamômetro digital de precisão. Foram utilizados os testes de Kolmogorov-Smirnov e "t" de Student com 5% de significância para ambos os testes. Os resultados evidenciaram diferença significativa entre a força inicial média liberada de 336,84g e 270,72g dos lotes 1 e 2, respectivamente, da marca U. Não houve diferença significativa entre os lotes da marca M apresentando força inicial média de 310,31g e 312,77g e da marca E com forças iniciais médias de 378,42 e 377,91. Os grupos M,U e E apresentaram os percentuais de 8,7%, 4,3% e 11,4%, respectivamente, de amostras elásticas liberando força inicial considerada padronizada. Pode-se concluir que as marcas Morelli® e Eurodonto® apresentaram força inicial padronizada quando variações entre os lotes foram investigadas. Porém, todas as marcas comerciais apresentaram percentual muito baixo de amostras elásticas com força inicial padronizada, considerando o intervalo de confiança (AU)

Abstract This study evaluated the standardization of the initial strength delivered by elastomeric chains of different lots of fabrication of three commercial brands. 762 colorless middle size samples of elastomeric chains were tested of the brands Morelli®, Uniden® and Eurodonto®. The elastics were distributed in 6 different groups: Group M (Morelli), Group U (Uniden) and Group E (Eurodonto), with 2 lots for each group. The elastics were maintained in a "jig" of 07 x 07 cm acrylic one that was fixed in a 55 X 15 cm wooden base. The elastics were activated in 50% of his initial lengths and the released inicial force was measured through a digital precision dynamometer. Kolmogorov-Smirnov tests were used and Student "t" test with 5% of significantion for both tests. The results showed significant difference between the mean initial released force of 336.84g and 270.72g of lots 1 and 2, respectively, of brand U. There was no significant difference between lots of brand M presenting average initial force of 310.31g and 312.77g and brand E with initial forces of 378.42 and 377.91. Groups M, U and E presented the percentages of 8.7%, 4.3% and 11.4%, respectively, of elastic samples releasing initial strength considered standardized. It can be concluded that the Morelli® and Eurodonto® brands showed standardized initial strength when variations between lots were investigated. However, all commercial brands had a very low percentage of elastic samples with standardized initial strength, considering the confidence interval (AU)

Asunto(s)

RESUMEN

Resumo Introdução: As ligaduras elastoméricas, também conhecidas popularmente como "elastics", são amplamente utilizadas na ortodontia fixa há bastante tempo. Contudo, além da função de apreender o arco aos slots dos bráquetes, elas também podem ser utilizadas para correção de pequenas giroversões dentárias. Diversas marcas comerciais já desenvolveram um modelo específico de acessório elastomérico para desempenhar essa função, nomeado como "rotator"; porém, por ter um tamanho padronizado, acabam provocando sobrecorreção do movimento em determinadas situações da prática clínica. Descrição da técnica: Desta maneira, o objetivo deste artigo é ilustrar a utilização e versatilidade dos famosos "elastics", posicionados de três formas diferentes nas aletas dos bráquetes, para realizar a correção de pequenas giroversões unitárias na ortodontia fixa. Conclusão: A versatilidade de seu uso permite diferentes magnitudes de correção com praticidade (AU)

Abstract Introduction: Elastomeric ligatures, popularly known as "elastics" have been widely used in orthodontic treatment with fixed appliances for a long time. However, in addition to the function of fixating the archwires to the bracket slots, they may also be used for the correction of minor tooth rotations. Various commercial brands have developed a specific model of elastomeric accessory to perform this function, known as "rotation wedge". However, as they are of a standardized size, they end up causing overcorrection of the movement in certain clinical situations. Technique description: This article aimed to illustrate the use and versatility of the famous "elastics", positioned in 3 different ways on the bracket tie wings to effectuate correction of small single tooth rotations in orthodontic treatment with fixed appliances. Conclusion: The versatility of their use allows different magnitudes of correction with practicality. (AU)

Asunto(s)

RESUMEN

BACKGROUND: This study aimed to verify the effects of bleaching toothpaste on colour stability, elastic properties, surface topography between aesthetic polyurethane and silicone elastomeric ligatures from different brands. METHODS: Elastomeric ligatures tested were: 1-Mini Single Case Ligature Stick (RMO-polyurethane); 2-Ligature "S" Shaped Dispenser (RMO-Silicone); 3-Sany-tie (GAC-translucent polyurethane); and 4-Sili-tie (GAC-translucent silicone). The ligatures were randomly assigned from the brackets of canines and lower incisors of 40 patients. The study had two phases of 30 days in which a different toothpaste was used, followed by a washout period of 30 days. After each phase, ligatures were submitted to colour checking, tensile strength, and SEM. RESULTS: The average of the ultimate tensile strength (m = 2.59; DP = 0.014) was higher in the control ligatures if compared to the tested ones (m = 2.24; DP = 0.014). There were no statistically significant differences between toothpastes regarding the type of ligature. Also, no interaction was observed between toothpastes in ligature's ultimate tensile strength and strain. The type of toothpaste did not minimize colour changes. CONCLUSION: In conclusion, there was no difference in colour stability and elastic properties between polyurethane or silicone aesthetic elastomeric modules. Whitening toothpastes had no impact on ligatures performance after 30 days in the oral cavity.

Asunto(s)

RESUMEN

Objective: Elastomeric chains are commonly used to apply force for orthodontic dental movements. However, force decay and discoloration are two important weak points of these materials. The present study intended to compare the force decay and color stability of different types of elastomeric chains. Material and Methods: This in vitro study evaluated 6 groups of elastomeric chains, including thermoplastic (TP) and thermoset (TS) chains made by the companies American Orthodontics (AO), Ormco (OR), and G&H Orthodontics (GH). The elastomeric chain forces were measured at the baseline, following 1 hour, 1 day, 1, 2, 3, 4, 5, and 6 weeks of stretching. The elongation required for the chains to exert a force of 250 g was calculated. ΔE of each group was calculated by a spectrophotometer following immersion in black tea solution for 6 days. Data were analyzed using the SPSS 22 software and the statistical methods of repeated measures analysis of variance and two-way analysis of variance (P<0.05). Results: The force decay of the TS chains were significantly lower than the TP chains in the 6-week study duration (P<0.05), and the lowest and highest force decay was observed in the products by AO and GH, respectively. The highest force degradation occurred during the first week in all groups. The elongation rate needed for the TS chains was significantly higher than the TP chains (P<0.05), and the highest elongation rate was observed in the products by OR. TS chains showed significantly higher color stability than TP chains, and products by OR and GH had better color stability than the products by AO. Conclusion: The present study showed that TS chains were superior to TP chains in force decay and color stability in all the brands studied. (AU)

Objetivo: Elásticos corrente são comumente utilizados para aplicar forças para a movimentação ortodôntica. Porém, a diminuição de força e descoloração são duas importantes fraquezas desses materiais. O presente estudo tem o objetivo de comparar a diminuição de força e estabilidade de cor de diferentes tipos de elásticos corrente. Material e Métodos: Este estudo in vitro avaliou 6 grupos de elásticos corrente, incluindo termoplástico (TP) e termofixo (TS) produzidos pelas empresas American Orthodontics (AO), Ormco (OR) e G&H Orthodontics (GH). A força dos elásticos corrente foram mensuradas no início, após 1 hora, 1 dia, 1, 2, 3, 4, 5 e 6 semanas de alongamento. A força de alongamento necessária para aplicação de 250g foi calculada. O ΔE de cada grupo foi calculado por um espectrofotômetro após a imersão em solução de chá preto por 6 dias. Os dados foram analizados utilizando o programa SPSS 22 e a análise estatística foi realizada por análise de variância e análise de variância dois fatores (p<0,05). Resultados: A diminuição da força do grupo TS foi significativamente menor que o grupo TP em 6 semanas de estudo (p<0,05), e o menor e maior valor de diminuição de força foi observado nos produtos da empresa AO e GH, respectivamente. A maior degradação de força ocorreu durante a primeira semana em todos os grupos. A taxa de alongamento necessária para o grupo TS foi significativamente maior que o grupo TP (p<0,05), e a maior taxa de alongamento foi observada nos produtos da empresa OR. Os elásticos TS obtiveram resultados significativamente maiores de estabilidade de cor que os elásticos TP, e os produtos da OR e GH tiveram melhor estabilidade de cor que oa produtos AO. Conclusão: O presente estudo demonstrou que os elásticos TS foram superiores aos elásticos TP em diminuição de força e estabilidade de cor em todas as marcas estudadas.(AU)

Asunto(s)

RESUMEN

The purpose of this in vitro study was to evaluate the force decrease of different elastomeric chains after different times: initial, 10 minutes, 1 day, 28 days and after mechanical brushing. Twenty orthodontic elastomeric chains segments were utilized for each commercial brand. Initially, the elastomeric chain of 15mm long were immediate stretched up to 20 mm in an Instron and the force was measured in gf. After all specimens were placed stretched on rectangular acrylic jigs with distance of 20 mm, immersed in deionized water at 37oC for 10 minutes and the force (gf) was measured again. Five test measurements of remaining force were made at the following time intervals: initial, 10 minutes, 1 day, 28 days and mechanical brushing. After 28 days, the acrylic plates with the specimens were adapted in the mechanical brushing machines (MSCT 3) and the elastomeric chains were submitted to mechanical brushing and the force (gf) measure again. The force (gf) was submitted to mixed-model ANOVA and Sidak post-hoc test (α=0.05). A statistically significant reduction in the force was found for all orthodontic elastomeric chain types after 1 day, 28 days and mechanical brushing (p<0.05). Morelli and 3M Unitek elastomeric chains showed significantly higher force than Abzil and GAC (p<0.05) after 1 day, 28 days and mechanical brushing. In conclusion, the force delivered by all elastomeric chains decayed rapidly over time. Morelli and 3M Unitek elastomeric chains consistently had a significantly greater force after mechanic brushing, while GAC the lowest.

Asunto(s)

RESUMEN

Hydroxyl-terminated polybutadiene (HTPB) is widely used in the formulations of solid propellants used in rocket motors. Furthermore, in general, chain extenders and short chain diols, such as 1,4-butanediol and 1,2-propanediol, can also be used in propellant formulations to improve mechanical properties, especially tensile strength. However, the incorporation of these diols can result in a considerable increase in the viscosity of the mixture during the processing of propellants. Thus, the present study evaluated the compatibility of these diols with the HTPB prepolymer, through a viscometric study, with the aim to determine the order of addition that results in greater homogeneity for the mixture. It was concluded that 1,4-butanediol, due to its larger chain size, has better compatibility with HTPB resin than 1,2-propanediol. On top of that, it was found that when the resin is added first, it results in mixtures with greater compatibility.

Asunto(s)

RESUMEN

Abstract The purpose of this in vitro study was to evaluate the force decrease of different elastomeric chains after different times: initial, 10 minutes, 1 day, 28 days and after mechanical brushing. Twenty orthodontic elastomeric chains segments were utilized for each commercial brand. Initially, the elastomeric chain of 15mm long were immediate stretched up to 20 mm in an Instron and the force was measured in gf. After all specimens were placed stretched on rectangular acrylic jigs with distance of 20 mm, immersed in deionized water at 37oC for 10 minutes and the force (gf) was measured again. Five test measurements of remaining force were made at the following time intervals: initial, 10 minutes, 1 day, 28 days and mechanical brushing. After 28 days, the acrylic plates with the specimens were adapted in the mechanical brushing machines (MSCT 3) and the elastomeric chains were submitted to mechanical brushing and the force (gf) measure again. The force (gf) was submitted to mixed-model ANOVA and Sidak post-hoc test (α=0.05). A statistically significant reduction in the force was found for all orthodontic elastomeric chain types after 1 day, 28 days and mechanical brushing (p<0.05). Morelli and 3M Unitek elastomeric chains showed significantly higher force than Abzil and GAC (p<0.05) after 1 day, 28 days and mechanical brushing. In conclusion, the force delivered by all elastomeric chains decayed rapidly over time. Morelli and 3M Unitek elastomeric chains consistently had a significantly greater force after mechanic brushing, while GAC the lowest.

Resumo O objetivo deste estudo in vitro foi avaliar a redução da força de diferentes cadeias elastoméricas após diferentes tempos: inicial, 10 minutos, 1 dia, 28 dias e após escovação mecânica. Vinte segmentos de cadeias elastoméricas ortodônticas foram utilizadas para cada marca comercial. Inicialmente, a cadeia elastomérica de 15 mm de comprimento foi esticada imediatamente até 20 mm na Instron e a força foi medida em (gf). Após, todas as amostras foram adaptadas esticadas em placas retangulares de acrílico na distância de 20 mm, imersas em água deionizada a 37o C por 10 minutos e a força (gf) foi medida novamente. Cinco medidas de força foram feitas nos seguintes intervalos de tempo: inicial, 10 minutos, 1 dia, 28 dias e após a escovação mecânica. Após 28 dias, as placas de acrílico com as amostras foram adaptadas na máquina de escovação (MSCT 3) e as cadeias elastoméricas foram submetidas a escovação mecânica e a medida de força (gf) novamente. Os dados da força (gf) foram submetidos a ANOVA modelo misto e teste post-hoc de Sidak (α = 0,05). Uma redução estatisticamente significativa na força foi encontrada para todos os tipos de cadeia elastomérica ortodôntica após 1 dia, 28 dias e escovação mecânica (p<0,05). As cadeias elastoméricas Morelli e 3M Unitek apresentaram força significativamente superior em relação a Abzil e GAC (p<0,05) após 1 dia, 28 dias e escovação mecânica. Em conclusão, a força distribuída por todas as cadeias elastoméricas decaiu rapidamente com o tempo. As cadeias elastoméricas Morelli e 3M Unitek consistentemente tiveram uma força significativamente maior após a escovação mecânica, enquanto GAC a mais baixa.

Asunto(s)

RESUMEN

La termografía es eficaz para detectar la temperatura de la superficie corporal y puede utilizarse como método auxiliar para diagnosticar procesos inflamatorios y para evaluar patrones de cicatrización, lo que permite su amplio uso en Medicina Veterinaria. El procedimiento ha ganado protagonismo por ser una técnica no invasiva, indolora, de bajo costo y segura, ya que elimina la necesidad del uso de contrastes, sedación y radiación. El objetivo de este artículo es analizar la eficacia del uso de la termografía en la evaluación de la biocompatibilidad en la reparación del tejido traqueal, así como identificar procesos inflamatorios tras la implantación de la prótesis impresa en nailon con impresión 3D asociada al elastómero termoplástico - PCTPE. Se dividieron quince conejos blancos de Nueva Zelanda (Oryctolagus cuniculus) machos en tres grupos de diferentes períodos de evaluación (siete, 15 y 30 días). Se implantaron prótesis tridimensionales tras la resección completa de tres anillos traqueales. La evaluación de las imágenes termográficas se realizó en el lugar de implantación de la prótesis traqueal justo antes del procedimiento quirúrgico e inmediatamente antes de la eutanasia. Hubo una diferencia significativa entre los grupos, ya los 30 días la temperatura mínima (p = 0,0357), media (p = 0,0135) y máxima (p = 0,0058) fue menor en comparación con los otros grupos...(AU)

Thermography is efficient for detecting body surface temperature and can be used as an auxiliary method for the diagnosis of inflammatory processes and in the evaluation of scarring patterns, which allows its wide use in Veterinary Medicine. The procedure has gained prominence, as it is a non-invasive, painless, low-cost and safe technique, since it does not require the use of contrasts, sedation and radiation. The objective of this article is to analyze the efficiency of the use of thermography in the evaluation of biocompatibility in tracheal tissue repair, as well as to identify inflammatory processes after implantation of the 3D printed impression prosthesis of nylon associated with the thermoplastic elastomer - PCTPE. Fifteen male New Zealand White rabbits (Oryctolagus cuniculus) were divided into three groups of different evaluation periods (seven, 15 and 30 days). Three-dimensional prostheses were implanted after complete resection of three tracheal rings. The evaluation of the thermographic images was performed at the place of implantation of the tracheal prosthesis just before the surgical procedure and immediately before euthanasia. There was a significant difference between the groups, and at 30 days the minimum (p = 0,0357), average (p = 0,0135) and maximum (p = 0,0058) temperature was lower when compared with the other groups...(AU)

A termografia é eficiente para detecção da temperatura da superfície corporal e pode ser utilizada como método auxiliar de diagnóstico de processos inflamatórios e na avaliação de padrões cicatriciais, o que permite sua ampla utilização na Medicina Veterinária. O procedimento tem ganhado destaque, pois trata-se de técnica não invasiva, indolor, de baixo custo e segura, pois dispensa a necessidade do uso de contrastes, sedação e radiação.  O objetivo desse artigo é analisar a eficiência do uso da termografia na avaliação da biocompatibilidade em reparação tecidual traqueal, bem como identificar processos inflamatórios após a implantação da prótese impressa em impressão 3D de náilon associado ao elastômero termoplástico- PCTPE. Quinze coelhos machos, da linhagem Nova Zelândia Branco (Oryctolagus cuniculus), foram distribuídos em três grupos de períodos de avaliação diferentes (sete, 15 e 30 dias). As próteses tridimensionais foram implantadas após ressecção completa de três anéis traqueais. A avaliação das imagens termográficas foi efetuada no local de implantação da prótese traqueal no momento anterior ao procedimento cirúrgico e imediatamente antes da eutanásia. Houve diferença significativa entre os grupos, sendo que aos 30 dias a temperatura mínima (p=0,0357), média (p=0,0135) e máxima (p=0,0058) foi menor quando comparado com os demais grupos...(AU)

Asunto(s)

RESUMEN

AIM: To assess the influence of elastomeric ligatures, subjected to a previous in vitro pigmentation process using different substances, on smile aesthetics during orthodontic treatment, from the perception of students and professionals. METHODS: Eight elastomeric ligatures of five commercial brands (3M/Unitek, American Orthodontics, Morelli, Ortho Technology, and Orthometric) (n=8) were immersed in coffee, Coca-Cola, and red wine for one minute per day, for 28 days; and another group of ligatures was immersed in artificial saliva. All samples were photographed and subsequently analyzed using the Adobe Photoshop software, by the RGB method. Afterwards, the pigmented ligatures were inserted in a patient wearing orthodontic brackets, and zoomed photographs of the smile were taken and presented to 40 evaluators, who filled in a satisfaction scale sheet to express their opinion on the smile aesthetics of each photograph. The color data were subjected to analysis of variance (ANOVA) and Tukey tests. RESULTS: The substance with the highest pigmentation potential was coffee (p< 0.05) followed by red wine (p< 0.05). Comparison among the brands used in this study showed that American Orthodontics and Orthometric had the lowest degree of pigmentation when immersed in coffee and red wine (p< 0.05), respectively. However, the brand that showed the highest level of satisfaction among the evaluators was Ortho Technology. CONCLUSIONS: The presence of pigmented elastomeric ligatures affected smile aesthetics, when compared with the control group.

Asunto(s)

RESUMEN

La termografía es eficaz para detectar la temperatura de la superficie corporal y puede utilizarse como método auxiliar para diagnosticar procesos inflamatorios y para evaluar patrones de cicatrización, lo que permite su amplio uso en Medicina Veterinaria. El procedimiento ha ganado protagonismo por ser una técnica no invasiva, indolora, de bajo costo y segura, ya que elimina la necesidad del uso de contrastes, sedación y radiación. El objetivo de este artículo es analizar la eficacia del uso de la termografía en la evaluación de la biocompatibilidad en la reparación del tejido traqueal, así como identificar procesos inflamatorios tras la implantación de la prótesis impresa en nailon con impresión 3D asociada al elastómero termoplástico - PCTPE. Se dividieron quince conejos blancos de Nueva Zelanda (Oryctolagus cuniculus) machos en tres grupos de diferentes períodos de evaluación (siete, 15 y 30 días). Se implantaron prótesis tridimensionales tras la resección completa de tres anillos traqueales. La evaluación de las imágenes termográficas se realizó en el lugar de implantación de la prótesis traqueal justo antes del procedimiento quirúrgico e inmediatamente antes de la eutanasia. Hubo una diferencia significativa entre los grupos, ya los 30 días la temperatura mínima (p = 0,0357), media (p = 0,0135) y máxima (p = 0,0058) fue menor en comparación con los otros grupos...

Thermography is efficient for detecting body surface temperature and can be used as an auxiliary method for the diagnosis of inflammatory processes and in the evaluation of scarring patterns, which allows its wide use in Veterinary Medicine. The procedure has gained prominence, as it is a non-invasive, painless, low-cost and safe technique, since it does not require the use of contrasts, sedation and radiation. The objective of this article is to analyze the efficiency of the use of thermography in the evaluation of biocompatibility in tracheal tissue repair, as well as to identify inflammatory processes after implantation of the 3D printed impression prosthesis of nylon associated with the thermoplastic elastomer - PCTPE. Fifteen male New Zealand White rabbits (Oryctolagus cuniculus) were divided into three groups of different evaluation periods (seven, 15 and 30 days). Three-dimensional prostheses were implanted after complete resection of three tracheal rings. The evaluation of the thermographic images was performed at the place of implantation of the tracheal prosthesis just before the surgical procedure and immediately before euthanasia. There was a significant difference between the groups, and at 30 days the minimum (p = 0,0357), average (p = 0,0135) and maximum (p = 0,0058) temperature was lower when compared with the other groups...

A termografia é eficiente para detecção da temperatura da superfície corporal e pode ser utilizada como método auxiliar de diagnóstico de processos inflamatórios e na avaliação de padrões cicatriciais, o que permite sua ampla utilização na Medicina Veterinária. O procedimento tem ganhado destaque, pois trata-se de técnica não invasiva, indolor, de baixo custo e segura, pois dispensa a necessidade do uso de contrastes, sedação e radiação.  O objetivo desse artigo é analisar a eficiência do uso da termografia na avaliação da biocompatibilidade em reparação tecidual traqueal, bem como identificar processos inflamatórios após a implantação da prótese impressa em impressão 3D de náilon associado ao elastômero termoplástico- PCTPE. Quinze coelhos machos, da linhagem Nova Zelândia Branco (Oryctolagus cuniculus), foram distribuídos em três grupos de períodos de avaliação diferentes (sete, 15 e 30 dias). As próteses tridimensionais foram implantadas após ressecção completa de três anéis traqueais. A avaliação das imagens termográficas foi efetuada no local de implantação da prótese traqueal no momento anterior ao procedimento cirúrgico e imediatamente antes da eutanásia. Houve diferença significativa entre os grupos, sendo que aos 30 dias a temperatura mínima (p=0,0357), média (p=0,0135) e máxima (p=0,0058) foi menor quando comparado com os demais grupos...

Asunto(s)

RESUMEN

ABSTRACT Aim: To assess the influence of elastomeric ligatures, subjected to a previous in vitro pigmentation process using different substances, on smile aesthetics during orthodontic treatment, from the perception of students and professionals. Methods: Eight elastomeric ligatures of five commercial brands (3M/Unitek, American Orthodontics, Morelli, Ortho Technology, and Orthometric) (n=8) were immersed in coffee, Coca-Cola, and red wine for one minute per day, for 28 days; and another group of ligatures was immersed in artificial saliva. All samples were photographed and subsequently analyzed using the Adobe Photoshop software, by the RGB method. Afterwards, the pigmented ligatures were inserted in a patient wearing orthodontic brackets, and zoomed photographs of the smile were taken and presented to 40 evaluators, who filled in a satisfaction scale sheet to express their opinion on the smile aesthetics of each photograph. The color data were subjected to analysis of variance (ANOVA) and Tukey tests. Results: The substance with the highest pigmentation potential was coffee (p< 0.05) followed by red wine (p< 0.05). Comparison among the brands used in this study showed that American Orthodontics and Orthometric had the lowest degree of pigmentation when immersed in coffee and red wine (p< 0.05), respectively. However, the brand that showed the highest level of satisfaction among the evaluators was Ortho Technology. Conclusions: The presence of pigmented elastomeric ligatures affected smile aesthetics, when compared with the control group.

RESUMO Objetivo: Avaliar a influência das ligaduras elásticas submetidas a um processo prévio de pigmentação in vitro, com diferentes substâncias, na estética do sorriso durante o tratamento ortodôntico, segundo a percepção de alunos e profissionais. Métodos: Oito ligaduras elásticas de cinco marcas comerciais (3M Unitek, American Orthodontics, Morelli, Ortho Technology e Orthometric) (n = 8) foram imersas em café, Coca-Cola e vinho tinto por um minuto por dia, por 28 dias, e outro grupo de ligaduras foi imerso em saliva artificial. Todas as amostras foram fotografadas e posteriormente analisadas no software Adobe Photoshop, pelo método RGB. Em seguida, as ligaduras pigmentadas foram inseridas em um paciente com braquetes ortodônticos, e fotografias ampliadas do sorriso foram tiradas e apresentadas a 40 avaliadores, que preencheram uma escala de satisfação para representar sua opinião sobre a estética do sorriso de cada fotografia. Os dados de cor foram submetidos à análise de variância (ANOVA) e testes de Tukey. Resultados: A substância com maior potencial de pigmentação foi o café (p< 0,05), seguido do vinho tinto (p< 0,05). A comparação entre as marcas utilizadas nesse estudo mostrou que a American Orthodontics e a Orthometric apresentaram o menor grau de pigmentação quando imersas em café e vinho tinto (p< 0,05), respectivamente. Porém, a marca que apresentou maior nível de satisfação entre os avaliadores foi a Ortho Technology. Conclusões: A presença de ligaduras elásticas pigmentadas afetou a estética do sorriso, quando comparada à do grupo controle.

Asunto(s)

RESUMEN

The aim of this article was to investigate the mechanical performance of magnetorheological polyurethane elastomers reinforced with different concentrations of carbonyl iron microparticles (CIPs) in which stress softening, energy dissipation, residual strains, microparticles orientation, and magnetic flux density effects will be considered. Other aspects, such as the determination of the dissipated energy during cyclic loading and unloading, were investigated by considering a pseudo-elastic network model that takes into account residual strains, magnetic field intensity, and the isotropic and anisotropic material behavior. Theoretical predictions confirmed that the material shear modulus becomes sensitive not only for higher concentrations of CIPs added into the elastomer material matrix, but also to the magnetic flux intensity that induces attractive forces between CIPs and to the strong bonds between these and the elastomer matrix. It was also found that the addition of CIPs when embedded into the polymer matrix with a predefined orientation enhances the material shear modulus as well as its capacity to dissipate energy when subjected to magnetic flux density in loading and unloading directions.

Asunto(s)

RESUMEN

Materiais de impressão com boa fluidez são essenciais para a captura das margens dos preparos dentais. O objetivo deste estudo, para tanto, foi avaliar, por meio do dispositivo de teste 'shark-fin' (3M ESPE), o escoamento de dois materiais de moldagem elastoméricos, um poliéter (PE) e um polivinilsiloxano (PVS). Foi realizada uma modificação no teste 'shark-fin' de modo a permitir a aproximação do estudo in vitro à realidade clínica, avaliando o comportamento de duas viscosidades de cada material aplicadas em um tempo único. Um poliéter (PE) de alta (Impregum Penta Soft / 3M ESPE) e de baixa viscosidade (Impregum Garant L Duosoft / 3M ESPE), um polivinilsiloxano (PVS) de alta (Express XT Penta H / 3M ESPE), de média (Express XT Pasta Fluida de Média viscosidade / 3M ESPE) e de baixa viscosidade (Express XT Pasta Fluida de Baixa viscosidade / 3M ESPE) foram divididos em 21 grupos (n=5) e testados isoladamente e combinados em proporções de 1 : 1, nos tempos de trabalho de 50, 80 e 120 s. Após, as alturas das barbatanas formadas foram medidas com o auxílio de um paquímetro digital. A análise estatística dos resultados foi realizada por análise de variância (ANOVA) one-way seguida pelo teste LSD post hoc (p=0,05). Verificou-se que os valores das alturas das barbatanas diferiram significativamente entre os materiais e a cada intervalo de tempo (p<0,05). As barbatanas diminuíram para todos os grupos com o aumento do tempo de trabalho, exceto para o grupo PE de baixa viscosidade e PVS em múltiplas misturas (alta associada à baixa viscosidade e alta associada à média viscosidade). Todos os grupos de PE apresentaram valores mais altos para as barbatanas formadas em comparação aos grupos de PVS, tanto em uma viscosidade quanto em duas viscosidades associadas, durante todo o tempo de trabalho. O poliéter mostrou um melhor comportamento no que diz respeito ao escoamento quando comparado ao polivinilsiloxano. (AU)

Good flowable impression materials are needed to capture preparation margins. The aim of this study was to evaluate, through the 'shark-fin' test device (3M ESPE), the flow of two elastomeric impression materials, a polyether (PE) and a polyvinylsiloxane (PVS). The 'shark-fin' test was modified to convey the approximation of the in vitro study to the clinical application, assessing the behavior of two viscosities of each material applied at one point in time. A high viscosity polyether (PE) (Impregum Penta Soft / 3M ESPE) and a low viscosity (Impregum Garant L Duosoft / 3M ESPE), a high viscosity polyvinylsiloxane (PVS) (Express XT Penta H / 3M ESPE), a medium viscosity (Express XT Regular Body / 3M ESPE) and a low viscosity (Express XT Light Body / 3M ESPE) were divided into 21 groups (n=5) and tested solely, and in a layered mixture of 1 : 1 at working times of 50, 80 and 120 s. Afterwards, the fin heights were measured with a digital caliper. The statistical analysis was performed by one-way analysis of variance (ANOVA) and LSD post hoc test (p=0,05). It was found that the 'shark-fin' values differed significantly among materials and at each time interval (p<0,05). The fin heights decreased for all groups with increasing of working time, except for the low viscosity PE and PVS in multiple mixtures (high with low viscosity and high with medium viscosity). The PE groups showed the highest 'shark-fins' compared to PVS, both in single and multiple mixtures, during the entire working time. The polyether impression materials had a better flow profile compared to polyvinylsiloxane groups. (AU)

Asunto(s)

RESUMEN

La mordida abierta anterior esquelética representa un escenario clínico de complejo abordaje para el ortodoncista. Actualmente, existen numerosas alternativas terapéuticas para su manejo, pero aún se tiene escasa evidencia respecto a su efectividad y estabilidad. Este reporte de caso describe el tratamiento de una mujer de 22 años con diagnóstico de mordida abierta esquelética severa que involucraba los dientes anteriores y posteriores hasta el segundo premolar, relación molar bilateral Clase III y mordida cruzada posterior bilateral. El plan de tratamiento consistió en realizar disyunción maxilar asistida quirúrgicamente, SARPE (acrónimo de Surgically Assisted Rapid Palatal Expansion) y posterior manejo con terapia mecánica de arcos multiloop con elásticos, terapia MEAW (Multiloop Edgewise Archwire). Dentro del período de estabilización de la disyunción, se comenzó la mecánica de arcos multiloop con elásticos, con lo que se redujo significativamente la mordida abierta. Después de 14 meses de tratamiento se consiguieron el control vertical y el sagital. La rápida y efectiva evolución de este caso indica que es posible que el procedimiento SARPE provoque aceleración de la terapia ortodóncica, en este caso MEAW, lo que se traduce clínicamente en resultados favorables para la corrección de la mordida abierta(AU)

The anterior skeletal open bite represents a complex clinical scenario for the orthodontist. Currently there are numerous therapeutic alternatives for its management, but there is still little evidence regarding its effectiveness and stability. This case report describes the treatment of a 22year-old woman with a diagnosis of severe skeletal open bite involving anterior and posterior teeth up to second premolar, bilateral Class III molar relationship and bilateral posterior crossbite. The treatment plan consisted of performing Surgically Assisted Rapid Palatal Expansion (SARPE) and subsequent management with mechanical Multiloop Edgewise Archwire therapy with elastics (MEAW therapy). Within the period of stabilization of the disjunction, the mechanics of multiloop arches with elastics was started, thereby significantly reducing the open bite. After 14 months of treatment, vertical and sagittal control was achieved. The speedy and effective evolution of this case indicates that it is possible that SARPE procedure causes orthodontic therapy acceleration, the MEAW therapy in this case, which is clinically translated into favourable results for the correction of the open bite(AU)

Asunto(s)

RESUMEN

STATEMENT OF PROBLEM: Maxillofacial elastomers undergo physical and mechanical degradation with disinfecting solutions. Solutions of Brazilian green propolis extract may be suitable alternatives for infection control of maxillofacial prostheses. However, their effects on the properties of the material are unknown. PURPOSE: The purpose of this in vitro study was to evaluate the effect of disinfection with solutions of Brazilian green propolis extract on the transmittance, translucency parameter, contrast ratio, and hardness of 2 maxillofacial elastomers (MDX4-4210 and MED-4014). MATERIAL AND METHODS: Fifty disk-shaped specimens (3×10 mm) of each elastomer were randomly and equally divided into 4 groups of disinfectant agents and 1 control group: 3 separate groups of 11% green propolis extracts including aqueous (PAQ), glycolic (PGL), and alcoholic (PAL), a 2% chlorhexidine gluconate (CHX) group, and the control group of distilled water. Specimens were subjected to disinfection by immersion 3 times a week for 60 days. Color differences (ΔE values) were calculated with CIELab and CIEDE2000 formulas. Optical parameters and Shore A hardness were determined at 2 time points: at baseline and after the period of specimen disinfection. Data were analyzed by parametric and nonparametric analysis of variance and by multiple-comparison tests (α=.05). RESULTS: The ΔE values of specimens immersed in 11% PAL were not clinically acceptable for either elastomer. Regarding translucency parameter and contrast ratio, the immersion in 11% PAL and 11% PGL resulted in greater opacity and lower translucency of the material. Mean Shore A hardness values were not statistically significantly different at baseline or after 60 days of immersion in the solutions. CONCLUSIONS: The solution of Brazilian green propolis extract tested showed changes in optical parameters. Elastomers immersed in 11% alcoholic green propolis extract showed clinically unacceptable color and translucency changes. All hardness values of the tested elastomers were clinically acceptable after immersion in all tested disinfectant groups.

Asunto(s)

RESUMEN

OBJECTIVE: Ideal heart valve solutions aim to provide thrombosis-free durability. A scaffold-based polycarbonate urethane urea tissue-engineered heart valve designed to mimic native valve microstructure and function was used. This study examined the acute in vivo function of a stented tissue-engineered heart valve in a porcine model. METHODS: Trileaflet valves were fabricated by electrospinning polycarbonate urethane urea using double component fiber deposition. The tissue-engineered heart valve was mounted on an AZ31 magnesium alloy biodegradable stent frame. Five 80-kg Yorkshire pigs underwent open tissue-engineered heart valve implantation on cardiopulmonary bypass in the pulmonary position. Tissue-engineered heart valve function was echocardiographically evaluated immediately postimplant and at planned study end points at 1, 4, 8, and 12 hours. Explanted valves underwent biaxial mechanical testing and scanning electron microscopy for ultrastructural analysis and thrombosis detection. RESULTS: All 5 animals underwent successful valve implantation. All were weaned from cardiopulmonary bypass, closed, and recovered until harvest study end point except 1 animal that was found to have congenital tricuspid valve dysplasia and that was euthanized postimplant. All 5 cases revealed postcardiopulmonary bypass normal leaflet function, no regurgitation, and an average peak velocity of 2 m/s, unchanged at end point. All tissue-engineered heart valve leaflets retained microstructural architecture with no platelet activation or thrombosis by scanning electron microscopy. There was microscopic evidence of fibrin deposition on 2 of 5 stent frames, not on the tissue-engineered heart valve. Biaxial stress examination revealed retained postimplant mechanics of tissue-engineered heart valve fibers without functional or ultrastructural degradation. CONCLUSIONS: A biodegradable elastomeric heart valve scaffold for in situ tissue-engineered leaflet replacement is acutely functional and devoid of leaflet microthrombosis.

Asunto(s)