Effect of folic acid coated-crosslinked urethane-doped polyester elastomer nerve conduit on promoting the repair of long distance peripheral nerve injury in rats / 中国修复重建外科杂志

OBJECTIVE@#To investigate the effect of folic acid coated-crosslinked urethane-doped polyester elastomer (fCUPE) nerve conduit in repairing long distance peripheral nerve injury.@*METHODS@#Thirty-six 3-month-old male Sprague Dawley rats weighing 180-220 g were randomly assigned to 3 groups, each consisting of 12 rats: CUPE nerve conduit transplantation group (group A), fCUPE nerve conduit transplantation group (group B), and autologous nerve transplantation group (group C), the contralateral healthy limb of group C served as the control group (group D). A 20-mm-long sciatic nerve defect model was established in rats, and corresponding materials were used to repair the nerve defect according to the group. The sciatic function index (SFI) of groups A-C was calculated using the Bain formula at 1, 2, and 3 months after operation. The nerve conduction velocity (NCV) of the affected side in groups A-D was assessed using neuroelectrophysiological techniques. At 3 months after operation, the regenerated nerve tissue was collected from groups A-C for S-100 immunohistochemical staining and Schwann cell count in groups A and B to compare the level of nerve repair and regeneration in each group.@*RESULTS@#At 3 months after operation, the nerve conduits in all groups partially degraded. There was no significant adhesion between the nerve and the conduit and the surrounding tissues, the conduit was well connected with the distal and proximal nerves, and the nerve-like tissues in the conduit could be observed when the nerve conduit stents were cut off. SFI in group A was significantly higher than that in group C at each time point after operation and was significantly higher than that in group B at 2 and 3 months after operation ( P<0.05). There was no significant difference in SFI between groups B and C at each time point after operation ( P>0.05). NCV in group A was significantly slower than that in the other 3 groups at each time point after operation ( P<0.05). The NCV of groups B and C were slower than that of group D, but the difference was significant only at 1 month after operation ( P<0.05). There was no significant difference between groups B and C at each time point after operation ( P>0.05). Immunohistochemical staining showed that the nerve tissue of group A had an abnormal cavo-like structure, light tissue staining, and many non-Schwann cells. In group B, a large quantity of normal neural structures was observed, the staining was deeper than that in group A, and the distribution of dedifferentiated Schwann cells was obvious. In group C, the nerve bundles were arranged neatly, and the tissue staining was the deepest. The number of Schwann cells in group B was (727.50±57.60) cells/mm 2, which was significantly more than that in group A [(298.33±153.12) cells/mm 2] ( t=6.139, P<0.001).@*CONCLUSION@#The fCUPE nerve conduit is effective in repairing long-distance sciatic nerve defects and is comparable to autologous nerve grafts. It has the potential to be used as a substitute material for peripheral nerve defect transplantation.

Force decay and discoloration of thermoplastic and thermoset orthodontic elastomeric chains / Diminuição de força e descoloração de elásticos corrente termoplásticos e termofixos

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)

Microenvironmental stiffness mediates cytoskeleton re-organization in chondrocytes through laminin-FAK mechanotransduction / 国际口腔科学杂志·英文版

Microenvironmental biophysical factors play a fundamental role in controlling cell behaviors including cell morphology, proliferation, adhesion and differentiation, and even determining the cell fate. Cells are able to actively sense the surrounding mechanical microenvironment and change their cellular morphology to adapt to it. Although cell morphological changes have been considered to be the first and most important step in the interaction between cells and their mechanical microenvironment, their regulatory network is not completely clear. In the current study, we generated silicon-based elastomer polydimethylsiloxane (PDMS) substrates with stiff (15:1, PDMS elastomer vs. curing agent) and soft (45:1) stiffnesses, which showed the Young's moduli of ~450 kPa and 46 kPa, respectively, and elucidated a new path in cytoskeleton re-organization in chondrocytes in response to changed substrate stiffnesses by characterizing the axis shift from the secreted extracellular protein laminin β1, focal adhesion complex protein FAK to microfilament bundling. We first showed the cellular cytoskeleton changes in chondrocytes by characterizing the cell spreading area and cellular synapses. We then found the changes of secreted extracellular linkage protein, laminin β1, and focal adhesion complex protein, FAK, in chondrocytes in response to different substrate stiffnesses. These two proteins were shown to be directly interacted by Co-IP and colocalization. We next showed that impact of FAK on the cytoskeleton organization by showing the changes of microfilament bundles and found the potential intermediate regulators. Taking together, this modulation axis of laminin β1-FAK-microfilament could enlarge our understanding about the interdependence among mechanosensing, mechanotransduction, and cytoskeleton re-organization.

Force degradation of elastomeric chains after storage time and mechanical brushing

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.

The influence of elastomeric ligatures pigmentation on smile aesthetics during orthodontic treatment

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.

Corrección de la mordida abierta anterior mediante técnica multiloop / Correction of anterior open bite by multiloop technique

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)

Development and characterization of a novel bulk-fill elastomeric temporary restorative composite

Abstract Objectives: This study investigated the physical and mechanical properties, antibacterial effect and biocompatibility of novel elastomeric temporary resin-based filling materials (TFMs) containing zinc methacrylate (ZM). Material and Methods: Experimental TFMs were prepared by mixing the zinc methacrylate with monomer, co-monomer, photoinitiator and fillers. A ZM concentration of 0 (control), 0.5% (Z0.5); 1% (Z1), 2% (Z2), or 5% (ZM5) wt% was added to the TFMs. Fermit-N (F) was used for comparison with the experimental material. Microleakage, water sorption/solubility, degree of conversion, depth of cure, ultimate tensile strength, and hardness were determined and compared. A modified direct contact test (DCT) with Enterococcus faecalis and a Streptococcus mutans' biofilm accumulation assay was carried out to evaluate the antimicrobial effect and cytotoxicity of the assay. Statistical comparisons were performed (α=5%). Results: The results showed that the physical and mechanical properties of the experimental TFMs with ZM are comparable with the properties of the commercial reference and some properties were improved, such as lower microleakage and water sorption, and higher ultimate tensile strength values. TFMs with ZM killed E. faecalis only after 1 h. Biofilm development of S. mutans was not affected by the inclusion of ZM in the experimental TFMs. Conclusions: The present findings suggest that the physical, mechanical and biological properties of the experimental TFMs with ZM are comparable with the properties of the commercial reference. However, some properties were improved, such as lower microleakage and water sorption, and higher ultimate tensile strength values.

Evaluation of degradation of force of esthetic elastomeric chains / Avaliação da degradação de força de correntes elastoméricas estéticas

Abstract Introduction Elastomers are considered important allies to orthodontic treatment and due to the aesthetic demand, aesthetic elastomers are increasingly used in adult patients. Objective The aim of this experimental in vitro study was to evaluate the degradation of force of esthetic elastomeric chains, of three different sizes: short, medium and long. Material and method For evaluating the degradation of force, 90 elastomeric chain segments were used, divided into 9 Groups (n=10), as follows: Morelli short elastomer, Morelli medium, Morelli long, Orthometric short, Orthometric medium, Orthometric long, American Orthodontic short, American Orthodontic medium and American Orthodontic long. Acrylic plates with pins were used to provide stretching of the elastomeric chains. The initial stretching force of the elastomeric chain was 150 grams, measured by a tensiometer. After this, they were prestretched to 50% of their original length, measured in an Instron 4411 Universal test machine, and placed on the seating pin on the plate. The plate was immersed in artificial saliva at 37 °C in a plastic receptacle, and removed for measurement after a time interval of 21 days. For statistical analysis, the methodology of mixed models for repeated measures in time and Tukey-Kramer test were used. Degradation of the forces was analyzed by 2-way analysis of variance (ANOVA) and the Tukey test. Result All the elastomeric chains showed statistically significant reduction in force (p<0.05). The American Orthodontic elastomeric chains showed higher reduction in force values, irrespective of the elastic size (p<0.05). Conclusion The three commercial brands studied underwent significant reduction in the quantity of force released; the American Orthodontic brand of elastomer showed the highest value of degradation in force.

Resumo Introdução Os elastômeros são considerados aliados importantes do tratamento ortodôntico e, devido à demanda estética, os elastômeros estéticos são cada vez mais utilizados em pacientes adultos. Objetivo O objetivo desse estudo experimental in vitro foi avaliar a degradação de forças geradas pelas cadeias elastoméricas estéticas, em três diferentes tamanhos curto, médio e longo. Material e método Para a avaliação da degradação da força foram utilizados 90 segmentos de cadeias elastoméricas, divididos em 9 grupos (n=10), sendo: elastômero Morelli curto, Morelli médio, Morelli longo, Orthometric curto, Orthometric médio, Orthometric longo, American Orthodontic curto, American Orthodontic médio e American Orthodontic longo. Foram utilizadas placas de acrílico com pinos que proporcionaram o estiramento das cadeias elastoméricas. A força inicial de estiramento da cadeia elastomérica foi de 150 gramas, medidas por um tensiômetro. Em seguida foram pré-estiradas em 50% do seu comprimento original, medidas em uma máquina Universal Instron 4411 e levadas ao pino de assentamento na placa. A placa foi imersa em um recipiente plástico com saliva artificial a 37 °C e removida após 21 dias para aferição. Foi aplicada metodologia de modelos mistos para medidas repetidas no tempo e teste de Tukey-Kramer. A degradação das forças foi analisada por análise de variância (ANOVA) "2 fatores" e teste de Tukey. Resultado Todas as correntes elastoméricas apresentaram redução estatisticamente significativa da força (p<0,05). As correntes elastoméricas da American Orthodontic apresentaram maior redução de força, independentemente do tamanho do elástico (p<0,05). Conclusão As três marcas comerciais estudadas sofreram uma redução significativa na quantidade de força liberada, sendo o elastômero da marca American Orthodontic o que apresentou maior degradação de força.

Uso de elastômero para delimitação do término do preparo em modelos odontológicos / Use of elastomer for delimitation of the preparation terminal edge in dental models

A comunicação entre o dentista e o técnico de prótese dentária é fundamental para o tratamento. A técnica convencional de troquelização de modelos consiste em sua individualização na região dos preparos através do recorte e eliminação do gesso fora do espaço correspondente ao sulco gengival na região do término. O objetivo deste artigo é descrever dois casos clínicos nos quais foi utilizada uma técnica inovadora de troquelização de modelos.

Communication between the dentist and the dental prosthesis technician is fundamental for treatments. The conventional technique of die casting models consists of their individualization in the preparations region, through plaster cutting and elimination outside the space corresponding to the gingival sulcus in the terminal region. The aim of this article is to describe two clinical cases in which an innovative technique of die casting models was used.

Effects of prestretch on stress relaxation and permanent deformation of orthodontic synthetic elastomeric chains / 대한치과교정학회지

OBJECTIVE: This study was performed to investigate an appropriate degree of prestretch for orthodontic synthetic elastomeric chains focusing on time-dependent viscoelastic properties. METHODS: Orthodontic synthetic elastomeric chains of two brands were prestretched to 50, 100, 150, and 200% of the original length in one and three cycles, and the hysteresis areas of the obtained stress-strain curves were determined. Acrylic plates were employed to maintain constant strain during the experiment. A total of 180 samples were classified into nine groups according to brand, and their stresses and permanent deformations were measured immediately after prestretch (0 hour), after 1 hour and 24 hours, and after 1, 2, 3, 4, 5, 6, 7, and 8 weeks. The relationship between stress relaxation and permanent deformation was investigated for various degrees of prestretch, and the estimated stress resulting from tooth movement was calculated. RESULTS: The degree of prestretch and the stress relaxation ratio exhibited a strong negative correlation, whereas no correlation was found between the degree of prestretch and the average normalized permanent strain. The maximal estimated stress was observed when prestretch was performed in three cycles to 200% of the original length. CONCLUSIONS: Although prestretch benefited residual stress, it did not exhibit negative effects such as permanent deformation. The maximal estimated stress was observed at the maximal prestretch, but the difference between prestretch and control groups decreased with time. In general, higher residual stresses were observed for product B than for product A, but this difference was not clinically significant.

Comparação da degradação da força de elásticos ortodônticos intermaxilares de látex e sintéticos quando submetidos à distensão em saliva artificial / Comparison of force degradation intermaxilary latex and synthetic orthodontic elastics distended in artificial saliva

Introdução: os elásticos intermaxilares sintéticos surgiram como uma alternativa para uso ortodôntico em pacientes com sensibilidade ao látex, porém, diferenças podem ser observadas quando comparados aos elásticos naturais de látex. Objetivo: comparar a quantidade de degradação de força dos elásticos intermaxilares sintéticos e de látex quando distendidos em saliva artificial, a fim de buscar parâmetros clínicos para o uso de um protocolo sobre a frequência de troca desses elásticos nas terapias ortodônticas em pacientes com sensibilidade ao látex ou não. Metodologia: foram utilizados dois grupos contendo 30 elásticos cada. O grupo 1 com 30 elásticos de látex da marca Morelli de força média e diâmetro de 5/16" e o grupo 2, 30 elásticos sintéticos, sem látex, também da marca Morelli de força média e diâmetro de 5/16". Eles foram distendidos 4cm e submersos em saliva artificial a 37 graus Celsius e tiveram força mensurada com dinamômetro ortodôntico ao início e nos intervalos de 24, 48, 72 e 120 horas após a imersão. A avaliação da degradação da força foi realizada calculando o percentual de força perdida em relação à força inicial em cada intervalo de tempo, para cada grupo testado separadamente e também entre eles. Resultados e Discussão: a média de valores dos elásticos tanto de silicone quanto de látex teve um percentual parecido quanto à degradação de forças, visto que após as primeiras 24 horas ocorreu o maior declínio de força, de aproximadamente 11% ambos os elásticos. Após 48 horas esse percentual não se alterou significativamente. Conclusão: elásticos devem ser trocados em até 48 horas para que a força aplicada se mantenha em índices aceitáveis.

Introduction: synthetic intermaxillary elastics have emerged as an alternative for orthodontic use in patients with latex sensitivity, but differences can be observed when compared to natural latex elastics. Objective: compare the amount of force degradation of synthetic intermaxillary elastics and latex when distended in artificial saliva in order to find clinical parameters for the use of a protocol on the frequency of exchange of these elastics in orthodontic therapies in patients with latex sensitivity or not. Method: for this, two groups containing 30 elastics were used. Group 1 with 30 medium strength and diameter 5/16 "Morelli latex elastics and group 2, 30 synthetic latex-free elastics, also of the medium strength and 5/16" diameter Morelli brand. They were stretched 4cm and submerged in artificial saliva at 37 degrees Celsius and had strength measured with orthodontic dynamometer at the beginning and at the intervals of 24, 48, 72 and 120 hours after immersion. The force degradation assessment was performed by calculating the percentage of force lost in relation to the initial force at each time interval, for each group tested separately and also between them. Results and discussion: the mean elastic values of both silicone and latex had a similar percentage for the degradation of forces, since after the first 24 hours the greatest force decline occurred, of approximately 11% both elastics. After 48 hours this percentage did not change significantly. Conclusion: elastics should be changed within 48 hours so that the force applied remains at acceptable rates.

Analysis in vitro of strength degradation comparing latex and non-latex elastics

Aim: This study was conducted in order to evaluate and compare the behavior of latex and non-latex elastics, as the loss of strength over time in vitro. Methods: The study evaluated 15 of each elastic material for the pre-selected times: 0, 1, 3, 12 and 24 hours. The rubber bands were transferred to the testing machine (EMIC DL-500 MF). The force values were recorded after stretching the elastic to a length of 25mm. Independent t-test was applied. Analysis of variance (ANOVA) was used to check the variation of the forces generated between those determined times. To identify between which times the difference was present, Tukey post-hoc test was accomplished. Results: As regards the initial forces (zero time), the values of force for non-latex elastic were slightly higher than the latex elastic. In subsequent times, the forces generated by the latex elastic showed higher values. Regarding the material degradation, at the end of 24 hours the highest percentage was observed for non-latex elastic. Conclusion: The latex elastic had a more stable behavior during the studied period compared with non-latex. Thus, it is suggested that the non-latex elastics should be changed more frequently and that larger initial forces must be applied than the látex elastics

Classification of Hip Shape and Customized Hip Augmentation in Asian Women

BACKGROUND: We classified the hips of Korean women into 6 types based on shape and contour, and have performed gluteal augmentation using Elastomere implants with lipoplasty of the flank, gluteal fold, and saddle bags of the thigh according to the hip type. METHODS: We analyzed the shapes and contour of the buttocks of 148 patients from September 2009 to September 2015. We performed buttock augmentation with implants using Gonzalez's XYZ method, as well as liposuction and fat injection lipoplasty of the surrounding areas in these 148 patients. RESULTS: We defined the following 6 types: the oval type (30%), the straight type (17%), the peach type (9%), the trapezoid type (20%), the heart type (11%), and the W type (13%). Ninety-seven patients underwent hip augmentation with an implant only or combined with lipoplasty, and 51 patients underwent lipoplasty for buttock shape correction. Patients were followed up for at least 3 months, with the longest follow-up being 4 years. Implants were removed postoperatively in 8 of 97 cases. CONCLUSIONS: The hip augmentation not only involves the simple insertion of implants, but also complex surgical procedures on the surrounding flank and thigh areas. Appropriate procedures should be utilized based on the 6 different hip types to ensure the best outcomes.

Quantification of Streptococcus mutans in Different Types of Ligature Wires and Elastomeric Chains

Abstract This study aimed to test the hypothesis that Streptococcus mutans contamination levels differ according to the type of the orthodontic ligature. Thirteen patients were selected. Each quadrant was randomly subjected to one of the following ligature-use protocols: I) elastomeric chain, II) steel ligature crossed over the archwire, III) steel ligature crossed under the archwire, and IV) steel ligature in a figure-eight pattern under the archwire. After seven days, the devices were removed and the Streptococcus mutans colony-forming unit count per mg of biofilm weight was determined. Twelve specimens (n=3) were also processed for scanning electron microscopy analysis. ANOVA and Tukey-Kramer test were used for comparisons to assess S. mutans differences between groups at a 5% significance level. There was no statistical difference in detectable levels of S. mutans among the groups (p=0.294). Scanning electron microscopy results showed abundant biofilms and microbial contamination in all groups. In conclusion, S. mutans contamination levels are similar in the different orthodontic ligatures.

Resumo Este estudo teve como objetivo testar a hipótese de que os níveis de contaminação de Streptococcus mutans diferem de acordo com o tipo de ligadura ortodôntica. Treze pacientes foram selecionados. Cada quadrante foi submetido aleatoriamente a um dos seguintes protocolos de uso de ligadura: I) ligadura elastomérica, II) ligadura de aço trançada sobre o arco, III) ligadura de aço trançada sob o arco e IV) ligadura de aço em um padrão de "oito" sob o arco. Após sete dias, os dispositivos foram removidos e a contagem das unidades formadoras de colônia de S. mutans por mg de peso de biofilme foi determinada. Doze espécimes (n = 3) também foram processados para análise por microscopia eletrônica de varredura. Análise de variância e teste de Tukey-Kramer foram utilizados para comparações a fim de avaliar as diferenças de níveis de S. mutans entre os grupos com significância de 5%. Não houve diferença estatisticamente significante em níveis detectáveis de S. mutans entre os grupos (p = 0,294). Os resultados da microscopia eletrônica de varredura mostraram biofilmes abundantes e contaminação microbiana em todos os grupos. Em conclusão, os níveis de contaminação de S. mutans são semelhantes nas diferentes ligaduras ortodônticas.

Mechanical properties of orthodontic wires on ceramic brackets associated with low friction ligatures / Propriedades mecânicas de fios ortodônticos em bráquetes cerâmicos associados com ligaduras de baixa fricção

Introduction: Few studies investigated the mechanical properties of orthodontic wires on ceramic brackets associated the ligatures. Objective: This study aimed to compare the load-deflection of orthodontic wires with round section of 0.016" made of stainless steel (SS), nickel-titanium (NiTi) and glass fiber-reinforced polymer composite (GFRPC). Material and method: Sixty specimens obtained from 10 sectioned pre-contoured arches (TP Orthodontics), were divided into 3 groups of 20 according to each type of material (1 esthetic-type wire and 2 not esthetic) and length of 50 mm. The methodology consisted of a 3-point bending test using esthetic ceramic brackets (INVU, TP Orthodontics, Edgewise, 0.022"x 0.025") as points of support. The tensile tests were performed on a mechanical test machine, at a speed of 10 mm/min, deflection of 1 mm, 2 mm and 3 mm. Friedman's Non Parametric Multiple comparisons test was used (P<0.05). Result: The nickel-titanium wire presented smaller load/ deflection compared with stainless steel. GFRPC wires had lower strength values among all groups evaluated (P<.05). The steel wire showed permanent deformation after 3 mm deflection, NiTi wire demonstrated memory effect and the esthetic type had fractures with loss of strength. Conclusion: It can be concluded that steel wires have high strength values, requiring the incorporation of loops and folds to reduce the load / deflection. NiTi and GFRPC wires produced low levels of force, however the esthetic wire was shown to fracture and break.

Introdução: Poucos estudos investigaram as propriedades mecânicas dos fios ortodônticos em bráquetes cerâmicos associados às ligaduras. Objetivo: O objetivo deste estudo foi comparar a carga-deflexão de fios ortodônticos com seção redonda de 0,016" de aço inoxidável (AI), níquel-titânio (NiTi) e composto de polímero reforçado com fibra de vidro (CPRFV). Material e método: Sessenta espécimes obtidos a partir de 10 arcos pré-contornos seccionados (TP Orthodontics), foram divididos em 3 grupos de 20 de acordo com cada tipo de material (1 fio estético e 2 não estético) e comprimento de 50 mm. A metodologia consistiu de um teste de flexão de 3 pontos usando bráquetes estéticos cerâmicos (INVU, TP Orthodontics, Edgewise, 0,022 "x 0,025") como pontos de suporte. Os ensaios de tração foram realizados em uma máquina de ensaios mecânicos, a uma velocidade de 10 mm / min, deflexão de 1 mm, 2 mm e 3 mm. Utilizou-se o teste não-paramétrico de comparações múltiplas de Friedman (P <0,05). Resultado: O fio de níquel-titânio apresentou menor carga / deflexão em relação ao aço inoxidável. Os fios CPRFV tiveram valores de resistência mais baixos entre todos os grupos avaliados (P <0,05). O fio de aço mostrou deformação permanente após deflexão de 3 mm, fio NiTi demonstrou efeito de memória e o tipo estético teve fraturas com perda de força. Conclusão: Pode-se concluir que os fios de aço têm valores de resistência elevados, exigindo a incorporação de alças e dobras para reduzir a carga / deflexão. Os fios NiTi e CPRFV produziram baixos níveis de força, porém o fio estético mostrou-se fraturado e quebrado.

Discoloration and force degradation of orthodontic elastomeric ligatures

ABSTRACT OBJECTIVE: The aim of the present study was to evaluate color changes and force degradation of orthodontic elastomeric ligatures in different stretching patterns during a 8-weeks period. METHODS: Two elastomers with the minimum and two with the maximum color changing, and gray elastomers of two brands (American Orthodontics and Ortho Technology) were selected according to an opinion poll with clinicians and color changes after 4 weeks of intraoral use were evaluated. These elastomers were mounted on special jigs fabricated using a CAD-CAM technique, underwent different stretching patterns and the force was measured in 0, 24 hours, 2, 4 and 8 weeks. During in vivo part of the study, force levels of elastomers were measured after 4 weeks on a material testing machine. Data were analyzed with four-way ANOVA and Tukey post hoc tests. RESULTS: All the elastomers showed color changing but the degree of color stability was significantly different. The mean force degradation was higher in 1-mm stretch groups. After 8 weeks, the average residual force of elastomers was 1.45 ± 0.18 N and the maximum force decay was seen in the elastomers that exhibited the maximum initial force. CONCLUSION: There is significant relationship between the stretching pattern and the amount of residual force of elastomers. Elastomers with higher initial forces exhibited higher percentages of force loss after 8 weeks. It seems that there is a relationship between initial color and color changing of elastomers.

RESUMO OBJETIVO: o objetivo do presente estudo foi avaliar as alterações de cor e a degradação da força de ligaduras elásticas em diferentes padrões de estiramento, durante um período de 8 semanas. MÉTODOS: duas ligaduras elásticas com alteração mínima de cor, duas com alteração máxima de cor e ligaduras elásticas na cor cinza de duas marcas comerciais (American Orthodontics e Ortho Technology) foram selecionadas de acordo com uma pesquisa de opinião com clínicos, e mediante a avaliação das alterações de cor após quatro semanas em uso intrabucal. Essas ligaduras elásticas foram montadas em jigs fabricados por meio da técnica CAD-CAM e foram expostas a diferentes padrões de estiramento, e a força foi medida nos tempos de 0h, 24h; 2, 4 e 8 semanas. Durante a parte in vivo do estudo, os níveis de força das ligaduras elásticas foram medidos após 4 semanas, em uma máquina de teste de materiais. Os dados foram analisados com os testes ANOVA de quatro vias e post-hoc de Turkey. RESULTADOS: todas as ligaduras elásticas mostraram alterações de cor, mas houve diferenças significativas quanto ao grau de estabilidade da cor. A média de degradação da força foi mais alta nos grupos com estiramento a 1 mm. Após 8 semanas, a média da força residual nas ligaduras elásticas foi de 1,45 ± 0,18 N e a maior degradação na força foi observada nas ligaduras elásticas que apresentaram a maior força inicial. CONCLUSÃO: há uma relação significativa entre o padrão de estiramento e a quantidade de força residual nas ligaduras elásticas. As ligaduras elásticas com as maiores forças iniciais exibiram as mais altas porcentagens de degradação da força após 8 semanas. É, também, possível que haja uma relação entre a cor inicial da ligadura elástica e sua alteração de cor.

Surface detail reproduction and dimensional accuracy of molds: influence of disinfectant solutions and elastomeric impression materials / Reprodução de detalhes da superfície e estabilidadedimensional de moldes: influência das soluçõesdesinfetantes e elastômeros

This study compared the surface detail reproduction anddimensional accuracy of molds after disinfection using 2% sodium hypochlorite, 2% chlorhexidine digluconate or 0.2% peracetic acid to those of molds that were not disinfected, forfour elastomeric impression materials: polysulfide (Light Bodied Permlastic), polyether (Impregum Soft), polydimethylsiloxane(Oranwash L) and polyvinylsiloxane (Aquasil Ultra LV). Themolds were prepared on a matrix by applying pressure, using aperforated metal tray. The molds were removed followingpolymerization and either disinfected (by soaking in one of thesolutions for 15 minutes) or not disinfected. The samples werethus divided into 16 groups (n=5). Surface detail reproductionand dimensional accuracy were evaluated using opticalmicroscopy to assess the 20 ­µm line over its entire 25 mm length. The dimensional accuracy results (%) were subjectedto analysis of variance (ANOVA) and the means were comparedby Tukey’s test (α=5%). The 20 ­µm line was completelyreproduced by all elastomeric impression materials, regardlessof disinfection procedure. There was no significant difference between the control group and molds disinfected with peraceticacid for the elastomeric materials Impregum Soft (polyether)and Aquasil Ultra LV (polyvinylsiloxane). The high­leveldisinfectant peracetic acid would be the choice material for disinfection.

Este estudo comparou a reprodução de detalhes da superfície e estabilidade dimensional de moldes obtidos após desinfecção utilizando hipoclorito de sódio 2%, digluconato de clorexidina 2%, ou ácido peracético 0,2% a moldes que não foram desinfetados com quatro elastômeros: polissulfeto (Light Bodied Permlastic), polieter (Impregum Soft), silicona reação porcondensação (Oranwash L) e silicona reação por adição (Aquasil Ultra LV). Os moldes foram preparados sobre matriz conten dolinhas de 20, 50 e 75 µm realizado sob pressão com moldeirade metal perfurada. Os moldes foram removidos após a polimerização e desinfetados (utilizando uma das soluções porimersão, armazenados em frascos fechados durante 15 minutos)ou não desinfetados. Assim, as amostras foram divididas em 16grupos (n=5). A reprodução detalhes da superfície e a precisão dimensional foram avaliadas usando microscopia óptica na linha 20 µm com 25 mm de comprimento, de acordo com a norma ISO 4823. Os resultados de precisão dimensional (%) foram submetidos à análise de variância (A NOVA) e as médias comparadas pelo teste de Tukey com 5% de nível de significância. A linha de 20 µm foi completamente reproduzida por todos os elastômeros, independentemente do processo de desinfecção. Não houve diferença estatisticamente significativa entre o grupo controle e moldes desinfetados com acido peracético para os elastômeros Impregum Soft (polieter) e Aquasil Ultra LV (siliconareação por adição). O desinfetante de alto nível ácido peracético seria o material de escolha para a desinfecção.

Evaluation of deflection forces of orthodontic wires with different ligation types

Abstract The aim of this study was to evaluate deflection forces of orthodontic wires of different alloys engaged into conventional brackets using several ligation types. Stainless steel, conventional superelastic nickel-titanium and thermally activated nickel-titanium archwires tied into conventional brackets by a ring-shaped elastomeric ligature (RSEL), a 8-shaped elastomeric ligature (8SEL) and a metal ligature (ML) were tested. A clinical simulation device was created especially for this study and forces were measured with an Instron Universal Testing Machine. For the testing procedure, the block representing the maxillary right central incisor was moved 0.5 and 1 mm bucco-lingually at a constant speed of 2 mm/min, and the forces released by the wires were recorded, in accordance with the ISO 15841 guidelines. In general, the RSEL showed lighter forces, while 8SEL and ML showed higher values. At the 0.5 mm deflection, the 8SEL presented the greatest force, but at the 1.0 mm deflection the ML had a statistically similar force. Based on our evaluations, to obtain lighter forces, the thermally activated nickel-titanium wire with the RSEL are recommended, while the steel wire with the 8SEL or the ML are recommended when larger forces are desired. The ML exhibited the highest force increase with increased deflections, compared with the elastomeric ligatures.

Polycaprolactone Triol–Citrate Scaffolds Enriched with Human Platelet Releasates Promote Chondrogenic Phenotype and Cartilage Extracellular Matrix Formation

In this paper we report the differentiating properties of platelet-rich plasma releasates (PRPr) on human chondrocytes within elastomeric polycaprolactone triol–citrate (PCLT–CA) porous scaffold. Human-derived chondrocyte cellular content of glycosaminoglycans (GAGs) and total collagen were determined after seeding into PCLT–CA scaffold enriched with PRPr cells. Immunostaining and real time PCR was applied to evaluate the expression levels of chondrogenic and extracellular gene markers. Seeding of chondrocytes into PCLT–CA scaffold enriched with PRPr showed significant increase in total collagen and GAGs production compared with chondrocytes grown within control scaffold without PRPr cells. The mRNA levels of collagen II and SOX9 increased significantly while the upregulation in Cartilage Oligomeric Matrix Protein (COMP) expression was statistically insignificant. We also report the reduction of the expression levels of collagen I and III in chondrocytes as a consequence of proximity to PRPr cells within the scaffold. Interestingly, the pre-loading of PRPr caused an increase of expression levels of following extracellular matrix (ECM) proteins: fibronectin, laminin and integrin β over the period of 3 days. Overall, our results introduce the PCLT–CA elastomeric scaffold as a new system for cartilage tissue engineering. The method of PRPr cells loading prior to chondrocyte culture could be considered as a potential environment for cartilage tissue engineering as the differentiation and ECM formation is enhanced significantly.

The effect of prolonged storage and disinfection on the dimensional stability of 5 vinyl polyether silicone impression materials

PURPOSE: Vinyl polyether silicone (VPES) has a different composition from other elastomeric impression materials as it combines vinyl polysiloxane (VPS) and polyether (PE). Therefore, it is important to study its properties and behavior under different test conditions. This study investigated the dimensional stability of 5 VPES consistencies when stored for up to 2 weeks, with and without using a standard disinfection procedure. MATERIALS AND METHODS: 40 discs of each VPES consistency (total 200) were made using a stainless steel die and ring as described by ANSI /ADA specification No. 19. 20 discs of each material were immersed in a 2.5% buffered glutaraldehyde solution for 30 minutes. Dimensional stability measurements were calculated immediately after fabrication and repeated on the same discs after 7 and 14 days of storage. The data was analyzed using two-way ANOVA with a significance level set at α = 0.05. RESULTS: The discs mean contraction was below 0.5% at all test times ranging from 0.200 ± 0.014 to 0.325 ± 0.007. Repeated measures ANOVA showed a statistically significant difference after 2-week storage between the disinfected and non-disinfected groups (P < .001). Although there was no statistically significant difference between the materials at the time of fabrication, the contraction of the materials increased with storage for 1 and 2 weeks. CONCLUSION: The dimensional changes of VPES impression discs after disinfection and prolonged storage complied with ANSI/ADA standard. The tested VPES impression materials were dimensionally stable for clinical use after disinfection for 30 minutes in glutaraldehyde and storage for up to 2 weeks.