Evolución de la osteosíntesis de los huesos largos y fijación por enclavado intramedular flexible / Evolution of Long Bone Osteosynthesis and Flexible Intramedullary Nail Fixation

Introducción: Se presenta la evolución histórica y científica de la osteosíntesis de huesos largos realizada con dos tipos de implantes intramedulares: Pines o varillas flexibles y clavos rígidos. Objetivo: Publicar un artículo científico que sirva de soporte teórico y práctico al personal en formación y, como punto de referencia y consulta a los ortopédicos y traumatólogos. Métodos: Se realiza una revisión bibliográfica retrospectiva de artículos sobre fracturas de los miembros publicadas en revistas de traumatología nacionales y extranjeras indexadas en las bases de datos MEDLINE y certificadas por el organismo de Ciencia Tecnología y Medio Ambiente, así como libros de relevancia sobre este tema y experiencias de los autores. Dadas las diferencias entre los dos tipos de implantes se estudiaron por separado la osteosíntesis con pines flexibles (Rush) y la realizada con clavos rígidos (Küntscher). Se seleccionaron las siguientes variables para el estudio: reducción, vía de acceso, penetración del implante, estabilidad, bloqueo, metal usado y consolidación. La fecha de incorporación de las innovaciones tecnológicas a la práctica quirúrgica fue enmarcada en tres momentos generacionales en el período de tiempo comprendido desde 1939 hasta la actualidad. Conclusiones: Esta revisión permitió identificar dos tipos de implantes intramedulares: los pines flexibles y los clavos rígidos. El estudio de sus características permitió organizarlos en generaciones para poder ubicar en el tiempo su contribución a los conocimientos que permiten devolver al paciente su vida activa(AU)

Introduction: This article discuses the historical and scientific evolution of long bone osteosynthesis performed with two types of intramedullary implants, flexible pins or rods and rigid nails. Objective: To publish a scientific article that serves as theoretical and practical support for staff in training and, as a point of reference and consultation for orthopedists and traumatologists. Methods: A retrospective bibliographic review of articles is carried out on limb fractures published in local and foreign trauma journals indexed in the MEDLINE databases and certified by CITMA, as well as relevant books on this topic and experiences of the authors. Given the differences between the two types of implants, we separately studied the osteosynthesis with flexible pins (Rush) from that performed with rigid pins (Küntscher). The variables selected for the study were reduction, access route, implant penetration, stability, locking, metal used, and consolidation. The inclusion of technological innovations to surgical practice was framed in three generational moments from 1939 to the present. Conclusions: Thow types of intramedullary implants were identifies from this revision: flexible pins and rigid nails. The study of their characteristics allowed to organize them into generations in order to locate their contribution to the knowledge allowing the patient to return to an active life over time(AU)

Prosthetic design and restorative material effect on the biomechanical behavior of dental implants: strain gauge analysis / Efeito do desenho protético e do material restaurador no comportamento biomecânico de implantes dentários: análise de extensometria

Objective: The purpose of this in vitro study was to evaluate the effect of different implant prosthetic designs with two restorative materials on biomechanical behaviour using strain gauge analysis. Material and Methods:6 different screw-retained implant restorations were designed and fabricated using a CAD/CAM system. These implants were divided into three main groups according to each design: group FB (fixed bridge); CB (cantilever bridge); SC (separate crowns). Each group was divided into two subgroups according to their restorative material: subgroup I ­ ultra translucent multi-layered zirconia (Kuraray Noritake Dental Inc, Japan); subgroup II ­ a combination of PEEK framework (BioHPP, Bredent, GmbH & Co.KG, Germany) and zirconia crowns (ultra-translucent multi-layered zirconia, Kuraray Noritake Dental Inc, Japan). Each subgroup was subjected to a vertical load of 100 N and their biomechanical behaviour was evaluated using a strain gauge (Kyowa, Japan) with a resistance of 120 Ω, length of 1 mm and width of 2.4 mm. For the implants, two strain gauges were positioned buccally and lingually, parallel to the long axis of the implant. For the restoration, two strain gauges were positioned buccally and lingually in the middle of it. The results were analyzed using three-way analysis of variance (ANOVA), followed by serial two-way and one-way ANOVAs at each level of the study, followed by Tukey's post hoc test P-values were adjusted for multiple comparisons using BENFORRONI correction and the significance level was set at P ≤ 0.05 for all tests. Results: FB showed the lowest strain values out of all 3 design groups. Moreover, the combination of PEEK and zirconia showed strain values smaller than full zirconia. The highest mean strain value was recorded in CB at 299.50 while the lowest mean strain peak value was recorded in group FB (74.50). The highest strain peak was recorded in CB subgroup I (3901.0 ± 195.91) and the difference had statistical significance (P-value < 0.01). Conclusion: the fixed bridge designed with PEEK framework and zirconia crowns was found to be more favorable in restoring the posterior edentulous area regarding strain measurements on the level of prosthetic components, implant and bone level. (AU)

Objetivo: O objetivo deste estudo in vitro foi avaliar o comportamento biomecânico de diferentes desenhos protéticos com dois materiais restauradores em implantes dentários usando análise por extensometria. Material e Métodos: 6 diferentes restaurações parafusadas em implantes foram projetadas e fabricadas usando um sistema CAD/CAM. Esses implantes foram divididos em três grupos principais de acordo com cada desenho: grupo PF (ponte fixa); PC (ponte cantilever); CI (coroas individuais). Cada grupo foi dividido em dois subgrupos de acordo com o material restaurador: subgrupo I ­ zircônia multicamada ultra translúcida (Kuraray Noritake Dental Inc, Japão); subgrupo II ­ uma combinação de estrutura PEEK (BioHPP, Bredent, GmbH & Co.KG, Alemanha) e coroas de zircônia (zircônia multicamada ultra translúcida, Kuraray Noritake Dental Inc, Japão). Cada subgrupo foi submetido a uma carga vertical de 100 N e seu comportamento biomecânico foi avaliado usando um extensômetro (Kyowa, Japão) com resistência elétrica de 120 Ω, comprimento de 1 mm e largura de 2,4 mm. Para os implantes, dois extensômetros foram posicionados pela vestibular e lingual, paralelos ao longo eixo do implante. Para a restauração, dois extensômetros foram posicionados no centro da estrutura, pela vestibular e lingual. Os resultados foram analisados usando análise de variância de três fatores (ANOVA), seguida de ANOVA dois fatores e um fator em cada estágio do estudo, seguidas pelo teste de Tukey. Os valores P foram ajustados para comparações múltiplas usando a correção de BENFORRONI e o nível de significância foi estabelecido em P ≤ 0,05 para todos os testes. Resultados: PF apresentou os menores valores de deformação de todos os 3 grupos de desenho. Além disso, a combinação de PEEK e zircônia apresentou valores de deformação menores do que a zircônia total. O maior valor médio de deformação foi registrado no PC em 299,50, enquanto o menor valor médio de pico de deformação foi registrado no grupo PF (74,50). O maior pico de deformação foi registrado no subgrupo PC I (3901,0 ± 195,91) e a diferença teve significância estatística (P-valor < 0,01). Conclusão: a ponte fixa projetada com estrutura de PEEK e coroas de zircônia mostrou-se mais favorável na restauração da área edêntula posterior em relação às medidas de deformação dos componentes protéticos, implante e nível ósseo (AU)

Computer-aided Design/Computer-aided Manufacturing (CAD/ CAM) Machines With Scanning and Milling Capabilities for Fabricating Custom Posts and Cores: A Narrative Review

@#Custom cast metal posts and cores are time-consuming to make, requiring several clinical and laboratory stages and the use of gold, cobalt-, or nickel-chromium. Aside from the numerous stages involved, a cast metal post and core has a significantly higher modulus of elasticity than the dentinal root structure and, as a result, is more likely to cause root fracture. Furthermore, the metal colour of the post and core, which always appears as a dark shadow beneath a ceramic crown, is an aesthetic concern. Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) of posts and cores is a potential fabrication option for overcoming the issues associated with cast metal posts and cores. Some of the time-consuming clinical and laboratory procedures can be eliminated by using a CAD/CAM machine, and tooth-colored materials can be milled to create custom posts and cores. The marginal and internal adaptation of the CAD/CAM produced posts and cores to the tooth structure, on the other hand, is highly dependent on the scanning accuracy and milling capability of the CAD/CAM machine. Because the majority of studies on dental CAD/ CAM have concentrated on the fabrication of fixed and removable prostheses, data on the marginal accuracy and internal adaptation of CAD/CAM produced posts and cores is limited. As a result, the aim of this review paper is to determine the current state of the market’s CAD/CAM machines in terms of their scanning and milling capability to produce custom posts and cores that match the marginal and fitting accuracy of cast metal posts and cores.

Trueness and precision of the reproduction of dental casts by the conventional, milling and 3D printing techniques / Fidelidade e precisão de modelos de trabalho reproduzidos pelas técnicas convencional, de fresagem e de impressão 3D

Objective: To compare the reproduction trueness and precision of dental casts made by the conventional, milling and 3D printing techniques. Material and Methods: From an upper right side half-arch reference model (RM), 72 models were obtained and divided into three groups: conventional (CM), milled (MM) and printed (PM). All models were scanned and converted into standard tessellation language (.STL) files. The files were superimposed using 3D analysis software, and statistical analysis was performed using the root mean square (RMS) values obtained. The Shapiro-Wilk test was used to assess normality, and the Kruskal-Wallis test was used to compare groups (ρ < ⍺; ⍺ = 0.05). The Mann-Whitney U test was used for multiple comparisons among groups (ρ < ਕ; ਕ = 0.017). Results: There were significant differences in trueness (ρ = 0.000; ρ <0.001) and precision (ρ = 0.000; ρ < 0.001) among the three dental cast groups. Regarding trueness, CM presented better results, followed by MM and PM. Regarding precision, MM showed better results, followed by PM and CM, which did not show significant differences. Conclusions: For dental cast reproduction the conventional technique has the best trueness and the milling technique has the best precision.(AU)

Objetivo: Comparar a fidelidade e precisão de reprodução de modelos de trabalho pelas técnicas convencional, de fresagem e de impressão 3D. Material e Métodos: A partir de um modelo de referência (MR) de uma hemi-arcada superior direita, foram obtidos 72 modelos divididos em três grupos: convencionais (MC), fresados (MF) e impressos (MI). Todos foram digitalizados e convertidos sob a forma de ficheiros .STL (standard tesselation language). Os ficheiros foram sobrepostos utilizando um software de análise 3D, e através dos valores RMS (raiz do valor quadrático médio) obtidos foi realizada a análise estatística. Para avaliação da normalidade foi utilizado o teste Shapiro Wilk e para a comparação entre grupos foi utilizado o teste Kruskal-Wallis (ρ < ⍺; ⍺ = 0.05). Para as comparações múltiplas entre grupos, foi utilizado o teste U de Mann-Whitney (ρ < ਕ; ਕ = 0.017). Resultados:Existem diferenças significativas de fidelidade (ρ = 0.000; ρ <0.001) e precisão (ρ = 0.000; ρ < 0.001) entre os três grupos. Em relação à fidelidade, MC apresentou melhores resultados, seguido por MF e MI. Em relação à precisão, MF apresentou melhores resultados, seguido por MI e MC, que não apresentaram diferenças significativas entre si. Conclusão: Para reprodução de modelos de trabalho, a técnica convencional é a que apresenta maior fidelidade e a técnica de fresagem a que apresenta maior precisão.(AU)

In vitro evaluation of marginal fit of zirconia-reinforced lithium silicate laminate veneers at two thicknesses using different CAD/CAM systems / Avaliação in vitro do ajuste marginal de folheados laminados de silicato de lítio reforçados com zircônia em duas espessuras usando diferentes sistemas CAD / CAM

Objective: The purpose of this in vitro study was to evaluate the marginal fit of laminate veneers made of zirconia-reinforced lithium silicate with two thicknesses using different CAD/CAM systems. Material and methods: 42 Laminate veneers milled from zirconia-reinforced lithium silicate were divided into three main groups according to milling machine used into: group X5, laminate veneers fabricated by inLab MCX5 milling machine; group CM, laminate veneers fabricated by Ceramill motion 2 milling machine; and group XL, laminate veneers fabricated by inLab MCXL milling machine. Each group was divided into two subgroups according to veneer thickness into: subgroup I, 0.5 mm thickness laminate veneers and subgroup II, 0.3 mm thickness laminate veneers. The marginal fit was measured using stereomicroscope. The results were tabulated and statistically analyzed using two-way ANOVA test followed by Tukey's post hoc test. Comparisons of main and simple effects were done utilizing Bonferroni correction. The significance level was set at (p ≤0.05) for all tests. Results: The mean( ± SD) highest marginal discrepancy was recorded in subgroup CMII at 85.45 ± 1.82 µm while the least mean marginal discrepancy was recorded in subgroup X5I (71.24 ± 2.64 µm). Conclusion: Both thicknesses(0.5 mm thickness and 0.3 mm thickness) and all tested CAD/CAM systems produced zirconia-reinforced lithium silicate laminate veneers with clinically acceptable marginal gaps; however, the closed CAD/CAM systems produced veneers with superior marginal fit than open systems at 0.3 mm thickness. The CAD/CAM system with the 5-axis milling machine produced the best marginal fit with 0.5 mm thickness. (AU)

Objetivo: O objetivo deste estudo in vitro foi avaliar a adaptação marginal de facetas laminadas de silicato de lítio reforçado com zircônia com duas espessuras, utilizando diferentes sistemas CAD / CAM. Material e métodos: 42 facetas laminadas fresadas a partir desilicato de lítio reforçado com zircônia foram divididos em três grupos principais de acordo com a fresadora usada em: grupo X5, facetas laminadas fabricados pela fresadora inLab MCX5; grupo CM, facetas laminadas fabricados por Ceramill motion 2; e grupo XL, facetas laminadas fabricados pelo inLab MCXL. Cada grupo foi dividido em dois subgrupos, de acordo com a espessura do laminado, em: subgrupo I, facetas laminadas com 0,5 mm de espessura e subgrupo II, facetas laminadas com espessura de 0,3 mm. A adaptação marginal foi medida usando estereomicroscópio. Os resultados foram tabulados e analisados estatisticamente usando o teste ANOVA de dois fatores seguido pelo teste post hoc de Tukey. Comparações dos efeitos principais e simples foram realizadas utilizando a correção de Bonferroni (P ≤ 0,05). Resultados: A maior discrepância marginal média ( ± DP) foi registrada no subgrupo CMII em 85,45 ± 1,82 µm, enquanto a menor discrepância marginal média foi registrada no subgrupo X5I 71,24 ± 2,64 µm. Conclusão: Ambas as espessuras (0,5 mm e 0,3 mm)e todos os sistemas CAD / CAM testados produziram facetas de laminado de silicato de lítio reforçadas com zircônia com lacunas clinicamente aceitáveis. No entanto, os sistemas CAD / CAM fechados produziam facetas com adaptação marginal superior aos sistemas abertos com 0,3 mm de espessura. O sistema CAD / CAM com a fresadora de 5 eixos produziu a melhor adaptação marginal com 0,5 mm de espessura (AU)

A comparative study on the effect of nano-pearl powder ground with different dispersion media / 中国组织工程研究

BACKGROUND: To retain more biological activity of organic matter and materials, it is necessary to grind and refine the pearl powder by physical method. The ball grinding method can retain the organic matter in the pearl powder and its activity to the greatest extent. The nanomaterials prepared by ball milling in different dispersion media exhibit different effects. OBJECTIVE: To compare nano-pearl powder milled with distilled water and anhydrous ethanol. METHODS: Nano-pearl powder was prepared by grinding with anhydrous ethanol and water as dispersion medium respectively. The prepared nano-pearl powder was compared by scanning electron microscope, transmission electron microscope, X-ray diffraction, Kjeldahl method and by determining amino acid content in foods. RESULTS AND CONCLUSION: (1) The nano-pearl powder prepared with anhydrous ethanol as dispersion medium was mainly round particles of different sizes (range, 30-50 nm), with the average grain size of 20 nm. The relative percentage of calcite calcium carbonate increased to 7%. The contents of protein and amino acid did not change obviously. (2) The nano-pearl powder prepared with distilled water as dispersion medium was mainly round particles of different sizes with the average grain size of 30 nm. There were irregular grain-like or block-like particles. The relative percentage of calcite calcium carbonate increased to 10%. The contents of protein and amino acid decreased. (3) These results showed that there was a significant difference in the particle size of the pearl powder ground with distilled water and anhydrous ethanol. The pearl powder prepared with anhydrous ethanol as the dispersion medium had a finer more uniform particle size.

Preparation and Quality Evaluation of Breviscapine Nanocrystals / 中国药房

OBJECTIVE：To prepare Brevisc apine（BRE） nanocrystals，and to evaluate its quality. METHODS ：BRE nanocrystal suspensions were prepared by media milling method. The diameter and amount of grinding beads ，grinding time ，type and ratio of stabilizer ，BRE ratio were investigated to screen the optimal technology and formulation with particle size and polydispersity index （PDI） as evaluation indexes. Using morphology ，color，particle size and PDI of BRE nanocrystals as evaluation index ，different lyoprotectants （50％ mannitol，5％ glucose，5％ lactose）and without lyoprotectant were investigated to screen the optimal lyoprotectant. Particle size analyzer ，scanning electron microscope （SEM），X-Ray diffraction （XRPD）， differential scanning calorimeter （DSC）were used to evaluate the quality of BRE nanocrystals which was prepared with the optimal technology and formulation. RESULTS ：The optimal technology and formulation of BRE nanocrystals included that particle size of 0.6 mm zirconia beads with the amount of 450 g，grinding time of 1 h，stabilizer of 15％ Tween-80，BRE ratio of 25％，without lyoprotectant. Prepared BRE nanocrystals were yellow powder with loose texture and uniform color. The average particle size of BRE nanocrystals was （283.10±3.08）nm，average PDI was （0.212±0.021）and average Zeta potential was （－38.48±0.39）mV. BRE nanocrystals were rod-like crystals ，uniform in distribution and had no change in crystalline state. Accumulative dissolution of BRE nanocrystals were （90.37±1.22）％ within 20 min. Under the condition of （40±2）℃ temperature and （75±5）％ relative humidity，BRE nanocrystals remained stable after being kept away from light for 3 months. CONCLUSIONS ：Established preparation method of BRE nanocrystals is simple and feasible. Prepared BRE nanocrystals show good stablility and dissolution.

Comparing accuracy of denture bases fabricated by injection molding, CAD/CAM milling, and rapid prototyping method

PURPOSE: The accuracy of denture bases was compared among injection molding, milling, and rapid prototyping (RP) fabricating method. MATERIALS AND METHODS: The maxillary edentulous master cast was fabricated and round shaped four notches were formed. The cast was duplicated to ten casts and scanned. In the injection molding method, designed denture bases were milled from a wax block and fabricated using SR Ivocap injection system. Denture bases were milled from a pre-polymerized block in the milling method. In the RP method, denture bases were printed and post-cured. The intaglio surface of the base was scanned and surface matching software was used to measure inaccuracy. Measurements were performed between four notches and two points in the mid-palatal suture to evaluate inaccuracy. The palatine rugae resolution was evaluated. One-way analysis of variance was used for statistical analysis at α=.05. RESULTS: No statistically significant differences in distances among four notches (P>.05). The accuracy of the injection molding method was lower than those of the other methods in two points of the mid-palatal suture significantly (P < .05). The degree of palatine rugae resolution was significantly higher in the injection molding method than that in other methods (P < .05). CONCLUSION: The overall accuracy of the denture base is higher in milling and RP method than the injection molding method. The degree of fine reproducibility is higher in the injection molding method than the milling or RP method.

Full mouth rehabilitation of patient with severe dental caries with implant fixed prosthesis fabricated with milling and 3D printing method: A case report / 대한치과보철학회지

Passive fit of prosthesis is an essential property of implant supported prosthesis for long term success and minimization of complications. And the property is determined mostly by fabrication procedure. There were limitations of extensive implant prosthesis because conventional casting method generate contraction error of long span prosthesis. However, Computer-aided design/Computer-aided manufacturing (CAD/CAM) technology of 3D printing and milling metal framework can overcome those limitations. This case is a full mouth rehabilitation using extensive implant fixed prosthesis. Removable interim prosthesis was made for esthetic, functional evaluation and a guide for implant insertion. After the insertion, implant fixed interim prosthesis was delivered. After additional evaluation and adjustment, final prosthesis was designed with CAD, the fabricated with CAM. Milling technique was used for anterior screw type implant superstructure and 3D printing technique was used for the anterior and posterior implant copings. Fit of the final restoration was favorable. The practitioner and patient were both esthetically and functionally satisfied with the final result.

Lung Function of Grain Millers Exposed to Grain Dust and Diesel Exhaust in Two Food Markets in Ibadan Metropolis, Nigeria

BACKGROUND: Despite growing concern over occupational exposure to particulate matter (PM) such as grain dust and diesel exhaust, information about the exposure level and health implications among workers in small-scale milling enterprises in developing countries like Nigeria has not been adequately documented. The purpose of this study was to assess the level of exposure to grain dust and diesel exhaust and effect on lung function among grain millers in food markets in Ibadan metropolis, Nigeria. METHODS: The study adopted descriptive cross-sectional design with a comparative approach. Sixteen grain milling shops each were randomly selected from two major food markets in Ibadan metropolis for indoor PM₁₀ and PM(2.5) monitoring. Seventy-two respondents each were proportionately selected from grain millers and shop owners for forced expiratory volume in one second and peak expiratory flow rate tests. RESULTS: The PM(2.5) concentrations for both market locations ranged between 1,269.3 and 651.7 μg/m³, while PM₁₀ concentrations were between 1,048.2 and 818.1 μg/m³. The recorded concentrations exceeded the World Health Organization guideline limit of 50 μg/m³ and 25 μg/m³ for PM(2.5) and PM₁₀, respectively. As compared with control group (2.1 L), significantly lower forced expiratory volume in one second value (1.61 L) was observed among the exposed group (p < 0.05). Likewise, significantly lower peak expiratory flow rate value (186.7 L/min) was recorded among the exposed group than the control group (269.51 L/min) (p < 0.05). CONCLUSION: Exposure to grain dust and diesel exhaust accentuated respiratory disorders with declines in lung functions amongst grain millers. Improved milling practices and engaging cleaner milling facilities should be adopted to minimize exposure and related hazards.

Accuracy of dental models fabricated by CAD/CAM milling method and 3D printing method

The purpose of this study was to evaluate the accuracy of a dental model fabricated using the CAD/CAM milling method and the 3D printing method. materials and method: this study was conducted in sequence of the digitization of the master model using an intraoral scanner, the manufacturing of working models (milling model, Multi-jet printing model and color-jet printing model) by using the scan data of the master model, the digitization of the working model by using a laboratory scanner, the superimposition of the digital data of the master model and working models using inspection software, and 3-dimensional analysis. ten measurements per group were done by one practitioner. one-way ANOVA and Tukey's post-hoc test were performed to compare the difference between the three groups. results: the overall difference in models caused by the manufacturing method was measured as 73.05µm±9.64µm, 84.52µm±4.78µm, and 96.05µm±5.43µm in the milling group, multi-jet printing group and color-jet printing group, respectively. the difference according to the shape of the teeth, the abutment teeth among the three parts was recorded with the lowest values as 19.18±2.08µm, 77.10±7.48µm, and 56.63±4.58µm. conclusions: dental models manufactured by the CAD/CAM milling method presented superior accuracy over the models manufactured by the 3D printing method. therefore, the use of optimized CAD software and appropriate materials is crucial for the fabrication accuracy of dental models.

Survey study on the Preference of Dental Medical Personnel for Dental CAD/CAM Milling Machines / 대한치과보철학회지

PURPOSE: Recently, according to the development of digital technology, computer aided design/computer aided manufacture (CAD/CAM) system is widely used for fabrication of various dental prostheses in the field of dentistry. This study aims to survey the present state and awareness of CAD/CAM system on domestic dental field, and to supply the advice for the application of the new system. MATERIALS AND METHODS: In this questionnaire survey was conducted for a total of 298 dentists, dental hygienist and dental technicians of the whole country including the dental hospital of Seoul National University for two months from November to December, 2016 through mail. RESULTS: The most important purpose to consider when purchasing a dental CAD/CAM milling machine were the performance of the milling machine (64.43%) and the use of milling machine was the highest with 49.33% of manufacturing for dental prosthesis and customized implant abutment. In addition, more than 60% of respondents answered positively about the purchase of new milling machine if the CAD/CAM milling machine was improved to satisfactory performance. CONCLUSION: This survey results show that the improved CAD/CAM milling machine would be play an important role in the dental industry in preparation for digitization and the 4th industrial revolution.

Nanocristais de hidroximetilnitrofural: preparação, caracterização fí­sico-quí­mica, avaliação da atividade in vitro antileishmania / Hydroxymethylnitrofurazone nanocrystals: optimization, characterization, leishmanicidal activity evaluation

De acordo com a Organização Mundial de Saúde, existem atualmente 17 doenças tropicais negligenciadas prevalentes em 149 países, afetando aproximadamente um bilhão de pessoas, a nível global. A leishmaniose, problema de saúde prevalente nos países em desenvolvimento, é endêmica em aproximadamente 98 países e territórios, com 350 milhões de pessoas em risco e 12 milhões de casos de infecção no mundo. A transmissão da doença ocorre pela picada de flebotomíneos fêmeas infectadas. Essa doença apresenta três formas principais: leishmaniose cutânea (LC), leishmaniose mucocutânea (LMC) e leishmaniose visceral (LV). Enquanto a leishmaniose cutânea é a forma mais comum da doença, a leishmaniose visceral é a mais grave e pode ser fatal se não for tratada. Em 2016, o Brasil reportou 3.626 e 12.690 casos de LC e LV, respectivamente. O candidato a fármaco hidroximetilnitrofural (NFOH) mostrou atividade contra o parasita da doença de chagas e da leishmaniose. Embora o NFOH seja promissor para o tratamento da leishmaniose, esse possui baixa solubilidade em água. A nanotecnologia tem sido empregada como plataforma para o desenvolvimento de formas farmacêuticas inovadoras com maior eficácia e segurança. A redução do tamanho de partículas em escala nanométrica permite aumentar a biodisponibilidade oral de fármacos pouco solúveis em água. Os nanocristais apresentam vantagens, tais como, o aumento da solubilidade de saturação e da velocidade de dissolução, decorrentes do aumento da área superficial da partícula. Além disso, esses apresentam maior adesividade às membranas biológicas, membrana celular e superfície do trato gastrointestinal. No presente trabalho utilizou-se a moagem por via úmida em escala reduzida para a obtenção dos nanocristais de NFOH. Diferentes tensoativos foram avaliados empregando o método selecionado, os tensoativos poloxamer 188 e poloxamer 407 foram os que favoreceram a redução do tamanho das partículas. Tal característica foi observada na caracterização físico-química das nanosuspensões de NFOH. A utilização desse método permitiu a obtenção de nanocristais de NFOH, com diâmetro hidrodinâmico médio (DHM) de 184,8 ± 0,5 a 325,9 ± 2,2 nm, índice de polidispersão (IP) de 0,21 ± 0,01 a 0,57 ± 0,01 e DHM de 191,3 ± 2,1 a 326,8 ± 4,6 nm e IP de 0,21 ± 0,01 a 0,50 ± 0,01, respectivamente para o poloxamer 188 e 407. O uso de ambos os tensoativos resultaram em distribuição monomodal de tamanho das partículas. As formulações foram obtidas por meio de planejamento fatorial completo e experimentos por superfície de resposta tendo como variáreis independentes as concentrações de NFOH, dos tensoativos e o tempo de moagem. A resposta, DHM, foi determinada utilizando espalhamento de luz dinâmica (DLS). Adicionalmente, as avaliações empregando calorimetria exploratória diferencial (DSC) e difração de raio X (DRX) revelaram que não houve interação entre o fármaco e os excipientes, assim como, não foi observada alteração na estrutura cristalina do NFOH. A microscopia eletrônica de varredura demonstrou a morfologia característica do estado cristalino. Além disso, a preparação liofilizada apresentou instabilidade após armazenamento por três meses a temperatura de 25 e 4 °C

According to the World Health Organization, there are currently 17 neglected tropical diseases prevalent in 149 countries, affecting approximately one billion people globally. Leishmaniasis, a health problem prevalent in developing countries, is endemic in approximately 98 countries and territories, with 350 million people at risk and 12 million cases of infection worldwide. The transmission of the disease occurs by the bite of infected female sandflies. This disease has three main forms: cutaneous leishmaniasis (CL), mucocutaneous leishmaniasis (MCL) and visceral leishmaniasis (VL). While cutaneous leishmaniasis is the most usual form of the disease, visceral leishmaniasis is the most serious and can be fatal if left untreated. In 2016, Brazil reported 3.626 and 12.690 cases of LC and LV, respectively. The drug candidate for hydroxymethylnitrofurazone (NFOH) showed activity against the parasite of chagas disease and leishmaniasis. Although NFOH is promising for the treatment of leishmaniasis, it has low solubility in water. Nanotechnology has been used as a platform for the development of innovative pharmaceutical forms with greater effectiveness and safety. Particle size reduction on the nanoscale enables the oral bioavailability of poorly water-soluble drugs to be increased. Nanotechnology has been used as a platform for the development of innovative pharmaceutical forms, improving effectiveness and safety. Particle size reduction on the nanoscale enables the oral bioavailability of poorly water-soluble drugs to be increased. Nanocrystals have advantages such as increased saturation solubility and dissolution rate due to the increase in the surface area of the particle. In addition, this present greater adhesiveness to the biological membranes, cell membrane and surface of the gastrointestinal tract. In the present work, wet scale milling was used to obtain NFOH nanocrystals. Different surfactants were evaluated using the selected method, poloxamer 188 and poloxamer 407 surfactants favored the reduction of particle size. This characteristic was observed in the physical-chemical characterization of NFOH nanosuspensions. The use of NFOH nanocrystals with a mean hydrodynamic diameter (DHM) of 184.8 ± 0.5 to 325.9 ± 2.2 nm, polydispersity index (IP) of 0.21 ± 0, 01 to 0.57 ± 0.01 for poloxamer 188 and DHM of 191.3 ± 2.1 at 326.8 ± 4.6 nm and IP of 0.21 ± 0.01 at 0.50 ± 0.01 for poloxamer 407, both with monomodal size distribution. The formulations were obtained by means of complete factorial planning and surface response experiments having as independent variables the concentrations of NFOH, surfactants and milling time. The response, DHM, was determined using dynamic light scattering (DLS). In addition, evaluations using differential scanning calorimetry (DSC) and X-ray diffraction (DRX) revealed that there was no change in the crystal structure of NFOH and interaction between the drug and the excipients. Scanning electron microscopy demonstrated the characteristic morphology of the crystalline state. In addition, the lyophilized preparation was instable after storage for three months at 25 and 4 ° C

Preparation and physicochemical properties of ultra-fine powder of Fritillaria unibracteata / 中草药

Objective The morphological and particle size distribution of Fritillaria unibracteata under different preparation conditions and the physicochemical property before and after grinding were studied, which provides the experimental basis for the particle size control and application of ultra-fine powder. Methods The single-factor experiment was carried out. The ultra-fine powder was prepared using ball milling method under different milling time, the weight ratio of ball to material, and rotating speed conditions. The powder morphology was observed by scanning electron microscopy. The particle size and particle size distribution of the powder was determined by laser particle size analyzer. The particle size, particle size distribution, expansion degree, total alkaloid content, and other properties of F. unibracteata powder before and after milling were compared. Results The optimum conditions for powder preparation were as follows: The grinding time was 0.5 h, the weight ratio of ball to material was 12:1, the rotating speed was 250 r/min. The volume average particle size of ultrafine powder was (26.92 ± 0.12) μm, and D90 was (45.15 ± 0.18) μm. After grinding, the particle size decreased, the particle size distribution became narrower, the expansion degree and angle of repose increased, the hygroscopicity of powder did not change significantly, the bulk density decreased, and the alcohol-soluble extract content and total alkaloid content increased greatly. Conclusion Moderate grinding can significantly reduce the size of F. unibracteata powder, improve the particle size distribution, increase the total alkaloid content, and help to improve bioavailability.

Preparation and pharmaceutical characteristics of naringenin nanocrystals / 中草药

Objective: To prepare and investigate the pharmaceutical characteristics of naringenin (NAR) nanocrystals. Methods: NAR nanocrystals were prepared by media milling combined with spray drying method. The mean particle size and polydispersity index (PDI) of NAR nanocrystals were analyzed by Malvern Zetasizer. The morphology of the nanoparticles was observed by scanning electron microscope (SEM). The crystalline state and the chemical structure of NAR before and after nanonization were characterized using X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), and fourier transform infrared spectrometry (FT-IR). Dissolution rate of NAR before and after nanonization were studied using rotary basket method. Results: The mean particle size of NAR nanocrystals was (400.7 ± 6.9) nm, and PDI value was 0.23. After nanonization, the crystalline state and chemical structure of NAR were not obviously altered, and the solubility was significantly increased (in pH 1.2 hydrochloric acid solution and pH 4.5 phosphate solution, P < 0.05; in pH 6.8 phosphate solution and water, P < 0.01). The dissolution was obviously improved, T50 and Td were visibly decreased (P < 0.01). Conclusion: The optimized process is stable and feasible for the preparation of NAR nanocrystals. NAR nanocrystals have a tiny and uniform particle size. After nanonization, NAR was still crystalline, the solubility and the dissolution were significantly increased, which can provide the basis for the further development of NAR.

Accuracy evaluation of dental models manufactured by CAD/CAM milling method and 3D printing method

PURPOSE: To evaluate the accuracy of a model made using the computer-aided design/computer-aided manufacture (CAD/CAM) milling method and 3D printing method and to confirm its applicability as a work model for dental prosthesis production. MATERIALS AND METHODS: First, a natural tooth model (ANA-4, Frasaco, Germany) was scanned using an oral scanner. The obtained scan data were then used as a CAD reference model (CRM), to produce a total of 10 models each, either using the milling method or the 3D printing method. The 20 models were then scanned using a desktop scanner and the CAD test model was formed. The accuracy of the two groups was compared using dedicated software to calculate the root mean square (RMS) value after superimposing CRM and CAD test model (CTM). RESULTS: The RMS value (152±52 µm) of the model manufactured by the milling method was significantly higher than the RMS value (52±9 µm) of the model produced by the 3D printing method. CONCLUSION: The accuracy of the 3D printing method is superior to that of the milling method, but at present, both methods are limited in their application as a work model for prosthesis manufacture.

Applicability of polyamide 12 intramedullary locked rods in the stabilization of induced humeral fracture in cockerels (white plymouth rock) - in vivo study / Aplicabilidade da haste intramedular bloqueada de poliamida 12 na estabilização de fratura umeral induzida em galos (Plymouth Rock Branca) - estudo in vivo

The aim of this study was to evaluate the use of polyamide 12 intramedullary rods in osteotomized humerus in cockerels (White Plymouth Rock) and analyze, by radiography and histopathology, bone consolidation and the formation of bone callus. Ten cockerels were subjected to transverse osteotomy of the right humeral diaphysis followed by the insertion of polyamide 12 locked rods, with two nails in each bone fragment. Radiographies obtained at the immediate pre and post-operative period, and every 7 days for 3 months revealed no perioperatory complications. Radiography revealed a radiopaque bone callus between the 4th and 5th week post-surgery. Histopathology detected an amphophylic material (polyamide 12 rod) in the intramedullary region and the proliferation of highly vascularized connective tissue between the rod and the cortical bone. This connective tissue was highly cellular with differentiation into osteoblasts. The collagen fibers varied from loose to dense and a differentiated bone matrix, containing osteocytes in gaps and the development of bone marrow, was also observed; indicating the formation of a bone callus without signs of implant rejection. The polyamide 12 intramedullary rod was effective in the stabilization of the fractures used in this experimental model, with no rejection reaction for at least 90 days.(AU)

O presente estudo teve como objetivo avaliar a implantação de hastes intramedulares de poliamida 12, em úmeros osteotomizados de galos (Plymouth Rock Branca), bem como avaliar a consolidação óssea, por meio da verificação da formação de calo ósseo, analisando exames radiográficos e histopatológicos. Os galos foram submetidos à osteotomia transversa da diáfise do úmero direito, sendo implantadas posteriormente as hastes de poliamida 12 bloqueada com dois parafusos em cada fragmento ósseo. Após o procedimento cirúrgico, foram realizadas radiografias nos momentos pré e pós-operatório imediato e, posteriormente, a cada sete dias, durante três meses, até a realização da eutanásia. Não houve complicações perioperatórias. Ao exame radiográfico, os animais apresentaram formação de calo ósseo radiopaco entre a quarta e quinta semanas de pós-operatório. Ao exame histopatológico, foi possível notar, em todos os animais, presença de material anfofílico (haste de poliamida 12) ocupando a região intramedular óssea, e entre a haste e as corticais ósseas, proliferação de tecido conjuntivo altamente vascularizado. Tal tecido apresentou-se altamente celular com diferenciação em osteoblastos. Notaram-se também fibras colágenas, variando de aspecto frouxo a denso, e observou-se formação de matriz óssea diferenciada com osteócitos em lacunas e formações de medula óssea, denotando formação de calo ósseo sem sinais de rejeição do implante. A haste intramedular de poliamida 12 foi eficaz para estabilização das fraturas utilizando-se esse modelo experimental, sem reação de rejeição pelo período de 90 dias.(AU)

Preparation of diosgenin nanosuspensions / 中成药

AIM To prepare diosgenin nanosuspensions.METHODS The nanosuspensions prepared by media milling method were solidificated by freeze drying method.With particle size and polydispersity index (PDI) as evaluation indices,stabilizer kind,ratio of diosgenin to stabilizer,ratio of preliminary nanosuspension volume to grinding bead amount,milling time,lyoprotectant kind and its amount as influencing factors,single factor test was applied to screening preparation and solidification processes.The morphology of nanosuspensions was observed,then the particle sizes and polydispersity indices of nanosuspensions and freeze-dried powder were determined.RESULTS The optimal conditions were determined to be 6:1 for ratio of diosgenin to Pluronic F127 (stabilizer Ⅰ),50:1 for ratio of diogenin to sodium dodecyl sulfate (SDS,stabilizer Ⅱ),1:4 for ratio of preliminary nanosuspension volume to grinding bead amount,120 min for milling time,and 8％ PEG-6000 and 2％ mannitol as lyoprotectants.The average particle size and polydispersity index of rod-like or flaky nanosuspensions were (348.1 ±14.2) nm and 0.244 ± 0.059,respectively,which were lower than those of freeze-dried powder.At room temperature,the particle sizes of nanosuspensions and freeze-dried powder remained stable within 35 d and 3 months,respectively.CONCLUSION The physical stability of diosgenin freeze-dried powder is superior to that of its nanosuspensions,which can be used after being reconstituted.

Preparation of diosgenin nanosuspensions / 中成药

AIM To prepare diosgenin nanosuspensions.METHODS The nanosuspensions prepared by media milling method were solidificated by freeze drying method.With particle size and polydispersity index (PDI) as evaluation indices,stabilizer kind,ratio of diosgenin to stabilizer,ratio of preliminary nanosuspension volume to grinding bead amount,milling time,lyoprotectant kind and its amount as influencing factors,single factor test was applied to screening preparation and solidification processes.The morphology of nanosuspensions was observed,then the particle sizes and polydispersity indices of nanosuspensions and freeze-dried powder were determined.RESULTS The optimal conditions were determined to be 6:1 for ratio of diosgenin to Pluronic F127 (stabilizer Ⅰ),50:1 for ratio of diogenin to sodium dodecyl sulfate (SDS,stabilizer Ⅱ),1:4 for ratio of preliminary nanosuspension volume to grinding bead amount,120 min for milling time,and 8％ PEG-6000 and 2％ mannitol as lyoprotectants.The average particle size and polydispersity index of rod-like or flaky nanosuspensions were (348.1 ±14.2) nm and 0.244 ± 0.059,respectively,which were lower than those of freeze-dried powder.At room temperature,the particle sizes of nanosuspensions and freeze-dried powder remained stable within 35 d and 3 months,respectively.CONCLUSION The physical stability of diosgenin freeze-dried powder is superior to that of its nanosuspensions,which can be used after being reconstituted.

Green, Low-cost Ball Milling-Hydrothermal Synthesis ofGraphene Quantum Dots and Applications / 分析化学

A ball milling method which is green with simple-manipulation and low-cost was used to prepare graphene as precursor for graphene quantum dots (GQDs) synthesis.Subsequently, GQDs with good dispersibility, uniform size distribution, average diameter of (4.80 ± 0.20) nm and 1-3 layers were prepared by one-step hydrothermal method.The morphology, structure and optical properties of the GQDs were characterized by high-resolution transmission electron microscopy (HRTEM), atomic force microscope (AFM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), UV-Vis absorption and fluorescence spectroscopy.Furthermore, the GQDs were used in label-free and specific detection of ferric ion (Fe.3+) with broad linear ranges of 2.0×10.-6-7.0×10.-4 mol/L and low detection limit of 1.8 × 10.6 mol/L (S/N=3).The possible mechanism was also discussed and the application of GQDs for Fe.3+ detection in tap water was demonstrated.Finally, based on their low cytotoxicity and excellent biocompatibility, the as-prepared GQDs were successfully applied to efficient cell imaging.This work provides a new way for preparation of carbon-based nanomaterials and build a foundation for deepening applications of GQDs in bio-/chem-analysis, bioimaging, etc.