Influence of traverse and waveone gold glider glide path files on the amount of apically extruded debris / Influência das limas glide path Traverse e Wave One Gold Glider na quantidade de detritos extruídos apicalmente

Objective: The aim of this study was to evaluate the effect of different glide path files on the amount of apically extruded debris. Material and Methods: Sixty single-canaled mandibular premolars were accessed and randomly divided into three groups (n= 20) according to the file used for glid path creation; group A using Traverse file, group B using WaveOne Gold Glider, group C using stainless steel K file. All teeth were then instrumented using the Reciproc system. The debris extruded apically during instrumentation were collected into pre-weighed Eppendorf tubes which were then stored in an incubator at 70 °C for 5 days. The weight of the dry extruded debris was established by subtracting the pre-instrumentation and post instrumentation weights of the Eppendorf tubes. The data were analyzed using one-way ANOVA test, and post hoc analysis. Results: WaveOne Gold Glider produced the least amount of apical extruded debris (0.41±0.25) followed by the Traverse group (0.59±0.20) then the K-file group (0.64±0.16) with a statistically significant difference (p=0.003). Conclusion: Apical extrusion of debris is inevitable during root canal cleaning and shaping. Creation of glide path using engine-driven files produces less amount of apically extruded debris compared to hand-driven K-files. (AU)

Objetivos: O objetivo deste estudo foi avaliar o efeito de diferentes limas glide path na quantidade de detritos extruídos apicalmente. Metodologia: Sessenta pré-molares inferiores com canal único foram acessados e divididos aleatoriamente em três grupos (n= 20) de acordo com a lima utilizada para criação do glid path; grupo A usando lima Traverse, grupo B usando WaveOne Gold Glider, grupo C usando lima K de aço inoxidável. Todos os dentes foram então instrumentados usando o sistema reciprocante. Os detritos extruídos apicalmente durante a instrumentação foram coletados em tubos Eppendorf pré-pesados que foram então armazenados em uma incubadora a 70°C por 5 dias. O peso dos detritos secos extruídos foi estabelecido subtraindo-se os pesos dos tubos Eppendorf antes e após instrumentação. Os dados foram analisados por meio do teste one-way ANOVA e análise post-hoc. Resultados: WaveOne Gold Glider produziu a menor quantidade de detritos apicais extruídos (0,41±0,25) seguido pelo grupo Traverse (0,59±0,20) e depois pelo grupo K-file (0,64±0,16) com uma diferença estatisticamente significativa (p=0,003). Conclusão: A extrusão apical de detritos é inevitável durante a limpeza e modelagem do canal radicular. A criação do glide path usando limas acionadas por motores produz menos quantidade de detritos extruídos apicalmente em comparação com as limas K manuais. (AU)

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

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

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

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

Biomechanical study of nickel-titanium three-dimensional memory alloy mesh and autologous bone in treatment of canine tibial plateau collapse fracture / 中国修复重建外科杂志

Objective: To evaluate the biomechanical effect of a nickel-titanium (Ni-Ti) three-dimensional memory alloy mesh in treating a canine tibial plateau collapse fracture model and to lay a foundation for further experiments in vivo. Methods: Sixteen tibial plateau specimens of 8 adult Beagle dogs were harvested. Twelve specimens were taken to prepare canine tibial plateau collapse fracture models (Schatzker type Ⅲ) and randomly divided into groups A, B, and C, with 4 specimens in each group. Four normal tibia specimens were used as blank control group (group D). In groups A and B, the bone defects were repaired with Ni-Ti three-dimensional shape memory alloy mesh combined with autologous bone and simple autologous bone respectively, and fixed with the lateral plate and screw. In group C, the bone defect was directly fixed with the lateral plate and screw. By using a biomechanical tester, a progressive load (0-1 700 N) was loaded vertically above the femoral condyle. The maximum failure load was recorded and the stiffness was calculated according to the load-displacement curve. Results: The maximum failure loads in groups A, B, C, and D were (1 624.72±7.02), (1 506.57±3.37), (1 102.00±1.83), and (1 767.64±24.56) N, respectively; and the stiffnesses were (129.72±20.83), (96.54±27.05), (74.96±17.70), and (169.01±35.62) N/mm, respectively. The maximum failure load and stiffness in group A were significantly higher than those in groups B and C, but which were significantly lower than those in group D ( P<0.05). Conclusion: Ni-Ti three-dimensional memory alloy mesh combined with autologous bone can repair the Schatzker type Ⅲ tibial plateau collapse fracture, which has better biomechanical properties than simple autologous bone grafting.

Controllable Growth of Nanoporous Metal Oxide Composites on Nickel-Titanium Alloy Fibers for Selective Solid-Phase Microextraction of Polycyclic Aromatic Hydrocarbons / 分析化学

Hydrothermal oxidation was used to prepare a nickel-titanium alloy ( NiTi ) solid-phase microextraction fiber. The experimental results demonstrated that a nanoporous NiTi oxide composite coating was in situ grown on the surface of NiTi substrate by direct oxidation in aqueous H2 O2 solution at 80℃. The resulting composite oxide coating included more nickel and less titanium. The prepared NiTi fiber with Ni-rich oxide coating was used to extract typical aromatic compounds coupled with HPLC-UV and exhibited good extraction selectivity for polycyclic aromatic hydrocarbons ( PAHs). The key factors affecting extraction efficiency of PAHs were examined. Under the optimized conditions, the calibration curves were linear in the range from 0. 05 to 500 ng / mL with correlation coefficients ≥0. 999, and the limits of detection were 0. 026-0. 056 ng / mL. Furthermore, the relative standard deviations ( RSDs) for intra-day and inter-day repeatability of the single fiber varied from 4. 8% to 6. 2% and from 5. 4% to 6. 5% for five replicates of PAHs at the spiking level of 50 ng / mL, respectively. The RSDs for the fiber-to-fiber reproducibility of five fibers prepared in different batches ranged from 6. 4% to 8. 4% . This method was suitable for selective enrichment and detection of target PAHs in environmental water samples with relative recoveries of 87. 4% -108. 2% and RSDs <8. 1% . Moreover, this novel NiTi fiber was mechanically strong and chemically stable, and its preparation was precisely controllable.

Nitinol corrosion under force stresses in simulated physiological fluid with and without fluorides / Corrosión de nitinol bajo tensiones de fuerza en fluido fisiológico simulado con y sin fluoruros

ABSTRACT Introduction: nickel-titanium (nitinol) wires may potentially corrode oral environments causing biocompatibility problems. The purpose of this study was to compare the behavior of corrosion of nitinol wires in artificial saliva with different levels of pH, fluoride concentration, and tension degrees. Methods: an experimental study applying four electrochemical techniques: corrosion potential, linear polarization resistance, Tafel curves, and electrochemical impedance spectroscopy. Samples were cemented on teeth simulating different crowding degrees (56 gf and 224 gf) at various levels of fluoride concentration (0% and 0.5%) and pH (4 and 7). Results: the corrosion strength values for a sample submerged at pH 4, 0% NaF during 5 hours is lower for a force of 224 gf than for 56 gf. When the electrolyte is added a concentration of 0.5% sodium fluoride, it increases polarization resistance for a force of 224 gf. Conclusion: this study confirmed the existence of oxides on the nickel-titanium surface, especially on the arch exposed for 14 days to pH 4 and 0.5% NaF.

RESUMEN Introducción: los alambres de níquel-titanio (nitinol) poseen potencial de corrosión en el medio bucal y pueden ocasionar problemas de biocompatibilidad. El propósito de este estudio fue comparar el comportamiento de corrosión que presentan los alambres de nitinol en saliva artificial con diferentes niveles de pH, concentración de fluoruros y grados de tensión. Métodos: se desarrolló un estudio de tipo experimental, aplicando cuatro técnicas electroquímicas: potencial de corrosión, resistencia a la polarización lineal, curvas de Tafel y espectroscopía de impedancia electroquímica. Los especímenes fueron cementados en dientes que simulaban diferentes grados de apiñamiento (56 gf y 224 gf), a diversos niveles de concentración de fluoruros (0% y 0,5%) y pH (4 y 7). Resultados: se observó que el valor de resistencia a la corrosión para una muestra sumergida a pH 4, 0% NaF y a 5 horas de inmersión es menor para la fuerza de 224 gf que para la de 56 gf. Cuando se le agrega al electrolito la concentración de fluoruro de sodio de 0,5%, aumenta la resistencia a la polarización para una fuerza equivalente de 224 gf. Conclusiones: se confirmó la existencia de óxidos sobre la superficie del níquel-titanio, especialmente en el arco expuesto durante 14 días a pH 4 y 0,5% en peso de NaF.

Theoretical evaluation of nickel-titanium MTWO series rotary files

Las limas rotatorias de níquel-titanio son un avance tecnológico que permite al odontólogo llevar a cabo tratamientos en conductos con morfologías irregulares Lamentablemente, estos instrumentos pueden fracturarse sin presentar señales visibles que permitan prevenir este accidente. Por lo tantoel objetivo del presente estudio fue evaluar teóricamente el comportamientomecánico de las limas rotatorias de Níquel-Titanio para uso en endodoncia Mtwo® para determinar cuál de losinstrumentos de la serie básica es el que presenta mayor probabilidad de fractura. Con este fin se realizó un análisis por medio del método de los elementos finitos utilizando modelos matemáticos de los instrumentos de la serie básica de las limas Mtwo®. Aestos instrumentos se les aplicaron cargas de flexión y torsión en condiciones normales y en condiciones extremas, para determinar cuáles presentaban los esfuerzos de Von Mises más altos. En una aproximación similar al uso normal, ninguno de los modelosde las limas alcanzó el limite máximo de falla por fractura. Ante un uso inadecuado, los modelos de las limas 10/0.04 y 25/0.06 mostraron los esfuerzos de Von Mises más altos tanto a flexión como a torsión respectivamente, por lo tanto se recomienda dar un solo uso a la lima 10/0.04 y a la lima 25/0.06 de Mtwo® para prevenir la fractura de estos instrumentos.

Nickel-Titanium rotary files are a technological development thatenables dentists to prepare irregularly shaped root canals withoutaltering them. Unfortunately, these files may fracture without anyprior visible warning signs. The aim of this study was to perform atheoretical evaluation of the mechanical behaviour of Mtwo®Nick-el-Titanium rotary files for endodontics, in order to determinewhich of the files in the basic series are most likely to fracture.Mathematical models of the Mtwo®basic file series were analyzedusing the finite elements method. Bending and torsion loads wereapplied to the files both under normal conditions and under extremeconditions, to determine which of them had the highest Von Misesstresses. When the approximation was similar to normal use, noneof the file models reached the maximum limit of failure by fracture.When used inadequately, file models 10/0.04 and 25/0.06 had thehighest Von Mises stresses for bending and torsion, respectively.Thus, it is recommended that Mtwo®files10/0.04 and 25/0.06should be used once only, to prevent fractures.

Preparation of Isoniazid-contained Drug Layer Alloy Stent and Its Dissolution in Vitro / 中国药房

OBJECTIVE:To prepare a nickel-titanium alloy stent coated by anti-tuberculotic isoniazid and study the dissolution of isoniazid in vitro.METHODS:The polyurethane which was used as film-former was mixed with isoniazid before being coated uniformly on the stent,then the stend was torrefied and dried so that the drug layer alloy stent was obtained.The content and accumulated dissolution in vitro of isoniazid from the stent was determined by ultraviolet spectrophotometry.RESULTS:The linear range of isoniazid was 5.0～30.0 ?g?mL-1(r=0.999 9)and its recovery rate was 99.67%(RSD=1.06%).A high accumluated dissolution rate of isoniazid was achieved,over 60% within the first 30 minutes,followed by a sustained dissolution in the following 8 h.CONCLUSION:The preparation method of the stent is simple and the quality is controllable.

The Biocompatibility of Human Osteoblasts to Porous Coated Nickel-Titanium Alloy (porous NiTi alloy) with Thermal Shape Memory / 대한정형외과연구학회지

PURPOSE: This research is to clarify utilization and efficiency of porous coated NiTi alloy by observing its affinity on human osteoblast. In this study, the biocompatibility of porous NiTi alloy was analyzed by investigating the biological activity and growth patterns of osteoblasts on NiTi alloy in vitro, followed by comparative analysis of their activity on commercial titanium based alloy (TBA) and tissue culture polystyrene (TCP), as a control. MATERIALS AND METHODS: The human osteoblasts were obtained from the iliac crest of a normal adult and cultured with routine maneuver. A seeding of cultured human osteoblasts to each group (NiTi alloy : experimental 1 group, TBA: experimental 2 group, TCP: control group) was done at the 15th day of primary culture. At the 4th, 7th and 10th seeding day, we observed the morphology of cultured cells on the surface of materials using scanning electron microscope and measured the amount of biosynthesis of cell protein and activity of alkaline phosphatase. RESULTS: In the scanning electron microscope study, the osteoblasts in experimental 1 and 2 groups were proliferated well in similar levels. However in control group, growth of osteoblasts were significantly retarded than experimental 1 and 2 groups. And the biosynthesis of proteins and activity of alkaline phosphatase were significantly increased in experimental 1 and 2 groups time dependently but decreased apparently in control group. CONCLUSION: The porous NiTi alloy which was proved to have good affinity and biocompatibility on human osteoblasts could be used as one of press-fit implants in orthopaedic fields.

Structure Design of Mushroom Shaped Surface Prosthesis of Femoral Head / 医疗卫生装备

Objective To address the medical problems, in treatment of avascular necrosis of the femoral head, on loosening and subsidence of the prosthesis of femoral head. A set of Mushroom Shaped Surface Prosthesis of Femoral Head was designed. Methods Based on biomechanical of the femoral head and the principle of transferring the force through femoral head while reducing stress-sheltered, nickel-titanium alloy and other new medical alloy materials were used to develop a prosthesis, which not only can be a weight-bearing device, but also promotes bone-growth. Results The prosthesis is novel, compact and little-volume, and the manipulation of surgery is convenient and secure. Conclusion The design of this prosthesis can provide new ways or ideas for designing the femoral head replacement prosthesis to solve problems on loosening and subsidence.