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1.
Braz. j. oral sci ; 20: e214873, jan.-dez. 2021. ilus
Article in English | LILACS, BBO | ID: biblio-1254742

ABSTRACT

Aim: To compare the marginal fit of lithium disilicate CAD/CAM crowns and heat-pressed crowns fabricated using milled wax patterns, and evaluate its effect on stress distribution in implantsupported rehabilitation. Methods: A CAD model of a mandibular first molar was designed, and 16 lithium disilicate crowns (8/group) were obtained. The crown-prosthetic abutment set was evaluated in a scanning electron microscopy. The mean misfit for each group was recorded and evaluated using Student's t-test. For in silico analysis, a virtual cement thickness was designed for the two misfit values found previously, and the CAD model was assembled on an implant-abutment set. A load of 100 N was applied at 30° on the central fossa, and the equivalent stress was calculated for the crown, titanium components, bone, and resin cement layer. Results: The CAD/CAM group presented a significantly (p=0.0068) higher misfit (64.99±18.73 µm) than the heat-pressed group (37.64±15.66 µm). In silico results showed that the heat-pressed group presented a decrease in stress concentration of 61% in the crown and 21% in the cement. In addition, a decrease of 14.5% and an increase of 7.8% in the stress for the prosthetic abutment and implant, respectively, was recorded. For the cortical and cancellous bone, a slight increase in stress occurred with an increase in the cement layer thickness of 5.9% and 5.7%, respectively. Conclusion: The milling of wax patterns for subsequent inclusion and obtaining heat-pressed crowns is an option to obtain restorations with an excellent marginal fit and better stress distribution throughout the implant-abutment set


Subject(s)
Microscopy, Electron, Scanning , Computer-Aided Design , Dental Marginal Adaptation , Dental Prosthesis, Implant-Supported , Finite Element Analysis , Dental Materials
2.
Rev. Ciênc. Plur ; 7(2): 47-60, maio 2021. ilus, tab
Article in Portuguese | LILACS, BBO | ID: biblio-1282724

ABSTRACT

Introdução:As atuaisresinas Bulk-Fill apresentamcomovantagens e propriedades: menor tempo clínico, baixa contração de polimerização, maior translucidez, entre outros. Objetivo:Avaliar a topografia superficial de restaurações com diferentes tipos de resina composta antes e após submetê-las a diferentes sistemas de acabamento e polimento. Metodologia:Confecção de100 corpos de prova, sendo 50 de cada composto resinoso, apresentando cinco grupos (n=10) sorteados de forma aleatória, de acordo com o sistema de acabamento e polimento empregado. Foram utilizadas as resinas Filtek Z350 XT e a Bulk Fill Filtek One Bulk Fill e os sistemas de acabamento e polimento: Discos de Lixa Sof-Lex Pop On Kit;Discos Diamantado Espiral Sof-Lex; Ponta Enhance e Broca Carbide Multilaminada nº 0283F, que foram comparados com superfície deixada pela Tira de Poliester (Controle Negativo). Após 7 dias de armazenamento em água destilada, os corpos de provaforam submetidos aoMicroscópio Eletrônico de Varredura.Resultados:Os corpos de provada resina Bulk Fill tiveram como melhor resultado o sistema de acabamento e polimentocom broca carbidee resultado não satisfatório com discodiamantado espiral Sof-lex, enquanto a ponta Enhance e lixa Sof-lex Pop Ontiveram resultados semelhantes. Os corpos de prova da resina Filtek Z350 XT tiveram melhor aspecto visual de lisura no grupo controle negativoe pior resultado no grupo com disco diamantado espiral Sof-lex. Conclusões:Dessa forma, o sistema que apresentou melhor resultado foi a broca Carbidena resina Bulk Fill, enquanto a Filtek Z350 XT apresentou-se melhor no grupo controle. Porém, ainda são necessáriosestudos para se chegar em um protocolo de acabamento e polimento mais eficiente (AU).


Introduction:The current Bulk-Fill resins have the following advantages and properties: less clinical time, low polymerization shrinkage, greater translucency, among others.Objective:Toevaluate the topography of restorations with different types of composite resin before and after submitting them to different finishing and polishing systems.Methodology:Manufacture of 100 specimens, 50 of each resin compound, presenting five groups (n = 10) drawn at random, according to the finishing and polishing system employed. Filtek Z350 XT resins and Bulk Fill Filtek One Bulk Fill andfinishing and polishing systems were used: Sof-Lex Pop On Kit Sanding Discs; Diamond Spiral Sof-Lex Discs; Tip Enhance and Multilaminated Carbide Drill nº 0283F, which were compared with the surface left by the Polyester Strip (Negative Control). After 7 days of storage in distilled water, the specimens were submitted to a Scanning Electron Microscope.Results:The Bulk Fill resin specimens had the best result of the finishing and polishing system with carbide drill and unsatisfactory result with Sof-lex spiral diamond disc, while the Enhance tip and Sof-lex Pop On sandpaper had similar results. The Filtek Z350 XT resin specimens had a better visual aspect of smoothness in the negative control group and a worse result in the group with Sof-lex spiral diamond wheel.Conclusions:Thus, the system that showed the best result was the Carbide drill in Bulk Fill resin, while Filtek Z350 XT was better in the control group. However, studies are still needed to arrive at a more efficient finishing and polishing protocol (AU).


Introducción:Las actuales resinas Bulk-Fill tienen las siguientes ventajas y propiedades: menor tiempo clínico, baja contracción de polimerización, mayor translucidez, entre otras.Objetivo: Evaluar la topografía de restauraciones con diferentes tipos de resina compuesta antes y después de someterlas a diferentes sistemas de acabado y pulido.Metodología: Fabricación de 100 probetas, 50 de cada resina compuesta, presentando cinco grupos (n = 10) extraídos al azar, según el sistema de acabado y pulido empleado. Se utilizaron resinas Filtek Z350 XT y Bulk Fill Filtek One Bulk Fill y sistemas de acabado y pulido: Discos de lijado Sof-Lex Pop On Kit; Discos Sof-Lex en espiral de diamante; Broca Realce de Punta y Carburo Multilaminado nº 0283F, que fueron comparadas con la superficie dejada por la Tira de Poliéster (Control Negativo). Después de 7 días de almacenamiento en agua destilada, lasmuestras se sometieron a un Las muestras de resina Bulk Fill tuvieron el mejor resultado del sistema de acabado y pulido con broca de carburo y un resultado insatisfactorio con el disco de diamante en espiral Sof-lex, mientras que la punta Enhance y el papel de lija Sof-lex Pop On tuvieron resultados similares. Las muestras de resina Filtek Z350 XT tuvieron un mejor aspecto visual de suavidad en el grupo de control negativo y un peor resultado en el grupo con disco de diamante en espiral Sof-lex.Conclusiones: Así, el sistema que mejor resultado mostró fue la broca Carbide en resina Bulk Fill, mientras que Filtek Z350 XT fue mejor en el grupo control. Sin embargo, aún se necesitan estudios para llegar a un protocolo de acabado y pulido más eficiente (AU).


Subject(s)
Surface Properties , Microscopy, Electron, Scanning/instrumentation , Composite Resins , Dental Polishing/instrumentation , In Vitro Techniques/methods , Brazil , Protocols , Polymerization
3.
Article in English | WPRIM | ID: wpr-879969

ABSTRACT

To investigate the effect of captopril on the dentin bonding durability of self-etch adhesive. Different concentrations of captopril ethanol solutions or captopril ethanol/water solutions were prepared to pretreat dentin as primer for the self-etch adhesives. The surface morphology of the dentin was observed with scanning electron microscopy (SEM). Based on the morphology analysis, the pretreatment condition was selected and two self-etch adhesives were employed to evaluate the improvement effect of the captopril pretreatment on the dentin bonding durability. : SEM showed that the pretreatment of captopril ethanol solutions and captopril ethanol/water solutions were able to remove the smear lay and partially expose collagen matrix. According to the SEM results, the pretreating condition of captopril ethanol/water solution with the pretreating time of was selected for further dentin bonding study. For Clearfil SEBOND system, the immediate bonding strength increased from to  (0.05]. For Clearfil S BOND system, there was no significant difference in the immediate bonding strength between the experimental group [(4.07) MPa] and the control group[(4.11) MPa]. But after one-year aging, the bonding strength of the experimental group was higher than that of the control group <0.05]. : The pretreatment with captopril ethanol/water solution increases the dentin bonding strength of the self-etch adhesive systems and also improves the bonding durability.


Subject(s)
Adhesives , Captopril , Dental Bonding , Dentin , Dentin-Bonding Agents , Materials Testing , Microscopy, Electron, Scanning , Resin Cements
4.
Braz. dent. sci ; 24(4, suppl 1): 1-7, 2021. ilus
Article in English | LILACS, BBO | ID: biblio-1352596

ABSTRACT

Objetivo: Este estudo in vitro objetivou caracterizar o teor de minerais e a morfologia das partículas de um dentifrício fluoretado contendo tecnologia REFIX e o teor de minerais e a morfologia da superfície do esmalte tratada com este produto. Material e Métodos: Blocos de esmalte bovino (n=5) foram obtidos (4×4×6 mm), desmineralizados (lesão de cárie artificial) e tratados (ciclagem de pH e escovação com dentifrício). Durante a ciclagem de pH de 7 dias (desmineralização e remineralização levaram 6 h e 18 h, respectivamente), o esmalte foi escovado por 5 min com uma escova dental elétrica antes de ser imerso em uma solução de remineralização. Avaliou-se a micromorfologia e os níveis elementares (% em peso) dos íons presentes no dentifrício e na camada formada sobre o esmalte após o tratamento. A morfologia da superfície foi avaliada por meio de microscopia eletrônica de varredura (MEV). As análises elementares foram realizadas usando um espectrômetro de energia dispersiva de raios-X (EDS). Resultados: A análise por MEV do dentifrício demonstrou uma distribuição de tamanho uniforme de partículas de forma regular que foram organizados esparsamente em "nanoclusters". A análise elementar da formulação do dentifrício demonstrou a presença de Si (silício), Na (sódio), P (fósforo) e F (flúor), entre outros. Observou-se também uma camada mineral na superfície de esmalte com espessura uniforme consistente em torno de 14 µm. Conclusão: De acordo com os resultados, conclui-se que a tecnologia REFIX modifica a superfície e subsuperfície da estrutura do esmalte, formando uma camada mineral rica em silício. (AU)


Objective: This in vitro study aimed at characterizing the mineral content and filler particle morphology of a fluoridated toothpaste containing REFIX technology and the mineral content and the morphology of the enamel surface treated with this product. Material and Methods: Bovine enamel blocks (n=5) were obtained (4×4×6 mm), demineralized (artificial caries lesion), and treated (pH cycling and brushing with the toothpaste). During the pH cycling, which lasted for 7 days (demineralization and remineralization took 6 h and 18 h, respectively), the enamel was brushed for 5 min using an electric toothbrush before being immersed in a remineralization solution. We evaluated the micromorphology and elemental levels (wt%) of ions present in the toothpaste and on the layer formed over the enamel following the treatment. The surface morphology was assessed using scanning electron microscopy (SEM). The elemental analyses were performed using an energy-dispersive X-ray spectrometer (EDS). Results: Scanning electron micrographs of the toothpaste demonstrated a uniform size distribution of regular-shaped fillers sparsely organized in nanoclusters. Elemental analysis of the toothpaste's formulation demonstrated the presence of Si (silicon), Na (sodium), P (phosphorus), and F (fluorine), among others. We also detected a mineral layer that had formed on the treated enamel surface; the layer had a consistent uniform thickness of ~14 µm. Conclusion: Based on the results, it can be stated that REFIX technology modifies the surface and subsurface of the enamel structure, forming a Si-rich mineral layer. (AU)


Subject(s)
Tooth Remineralization , Microscopy, Electron, Scanning , Dental Enamel , Dentifrices
5.
Braz. dent. sci ; 24(2): 1-9, 2021. tab, ilus
Article in English | LILACS, BBO | ID: biblio-1178281

ABSTRACT

Objective: was to evaluate fracture resistance of zirconia monolithic restorations after aging procedures. Material and methods: Monolithic translucent zirconia 3-unit FPDs were fabricated using Cerec inLab CAD/CAM system on 2 stainless steel dies with a uniform 120 degrees circumferential deep chamfer finish line of 1 mm width. FPDs were divided into 2 groups, first group (Group A) was subjected to aging procedures in an autoclave at hydrothermal conditions 134 oC /2 bars for 5 hours. Second group (Group B) was not subjected to any aging procedures (control group). All specimens of each group were loaded compressively in a universal testing machine at cross head speed 0.5 mm/min until fracture occurred. The percentage of monoclinic (m) phase was detected by XRD device. Scanning electron microscope (SEM) was used to examine the fractured surfaces for Aged TZI (Group A) and Non-aged TZI (Group B). Student's t-test was used to compare between fracture resistances of both groups. The significance level was set at P ≤ 0.05. Results: The fracture resistance mean (SD) values of non-aged TZI (Group B) was 2406.9 ± 306.8 N which showed statistically significantly higher than that of aged group (Group A) which was 1964.5 ± 234.5 N. The percentage of monoclinic (m) phase detected by XRD device software in non-aged TZI (Group B) was nearly 0 weight % and in aged TZI (Group A) was about 42 weight %. Conclusions:Accelerated artificial aging decreases the fracture resistance of monolithic TZI FPDs. (AU)


Objetivo: Foi avaliar a resistencia à fratura de restaurações de zircônia monolítica após procedimentos de envelhecimento.Material e Métodos: 3 unidades de FPDs de zircônia monolítica translucida foram fabricadas utilizando o sistema Cerec inLab CAD/CAM com 2 matrizes de aço inoxidável com uma linha de acabamento de chanfro profundo circunferencial de 120 graus de largura de 1 mm. As FPDs foram divididos em dois grupos, primeiro grupo (Grupo A) foi submetido a procedimentos de envelhecimento em autoclave em condições hidrotérmicas de 134 °C /2 bars por 5 horas. O segundo grupo (Grupo B) não foi submetido a nenhum processo de envelhecimento (grupo controle). Todos os espécimes de cada grupo foram carregados compressivamente em uma maquina de teste universal na velocidade de 0.5 mm/min até a fratura ocorrer. A porcentagem da fase monoclínica (m) foi detectada pelo dispositivo XRD. O microscópio eletrônico de varredura (MEV) foi utilizado para examinar as superfícies fraturadas para TZI envelhecido (Grupo A) e TZI não envelhecido (Grupo B). O teste t de estudantes foi usado para comparar as resistências à fraturas de ambos os grupos. O nível de significância foi estabelecido em P ≤ 0.05. Resultados: Os valores médios de resistência à fratura (SD) do TZI não envelhecido (Grupo B) foi 2406.9±306.8 N, o qual se mostrou estatisticamente significativamente maior do que o grupo envelhecido (Grupo A), que foi 1964.5±234.5 N. A porcentagem da fase monoclínica (m) detectada pelo software do dispositivo XRD em TZI não envelhecido (Grupo B) foi próximo de 0% em peso e em TZI envelhecido (Grupo A) foi cerca de 42% em peso. Conclusão: O envelhecimento artificial acelerado diminui a resistência à fratura de FPDs TZI monolítico (AU)


Subject(s)
Microscopy, Electron, Scanning , Flexural Strength
6.
Braz. dent. sci ; 24(2): 1-9, 2021. tab, ilus
Article in English | LILACS, BBO | ID: biblio-1177588

ABSTRACT

Objective: The purpose of the present study was to synthesize and characterize lithium disilicate glass-ceramics through the Li2O-SiO2system for determining the most satisfactory sintering parameter by evaluating the crystalline composition, microstructure and mechanical properties. Material and methods: The glass-ceramics were prepared from a glass precursor by means of the melting/cooling technique with a composition of 33.33 Li2O and 66.67 SiO2 (mol.%). The specimens were compressed by the uniaxial pressing technique and three different thermal treatments were used for sintering: 850 °C (Group 1), 900 °C (Group 2), and 950 °C (Group 3), which were determined based on the differential scanning calorimetry (DSC) result. The glass-ceramics were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Archimedes method, microhardness and biaxial flexural strength analyses. Results: The results regarding XRD predominantly showed lithium disilicate phase for all the heat treatments performed. Moreover, grains with a needle form were more predominantly observed in the SEM images for Group 3, as well as a higher densification and consequently higher mechanical properties. In contrast, Group 1 presented the lowest mechanical properties and densification, as well as the highest porosity. Conclusion: The present study demonstrated how extremely important it is to follow the heat treatment recommended by the manufacturers of ceramics, including time and temperature, which possess direct effects in the crystalline phase formation, as well as in the material's microstructure and mechanical properties (AU)


Objetivo: O presente estudo teve como objetivo sintetizar e caracterizar uma vitrocerâmica de dissilicato de lítio através do sistema Li2O-SiO2para determinar o parâmetro de sinterização mais satisfatório através da avaliação da composição cristalina, microestrutura e propriedades mecânicas. Material e Métodos: As vitrocerâmicas foram preparadas a partir de um vidro precursor pelo método fusão/resfriamento utilizando a composição de 33.33 Li2O e 66.67 SiO2 (mol.%). As amostras foram prensadas utilizando uma técnica de prensagem uniaxial e três tratamentos térmicos diferentes foram utilizadas para sinterização: 850 °C (Grupo 1), 900 °C (Grupo 2), e 950 °C (Grupo 3), que foram determinados através do resultado da análise diferencial de calorimetria. As vitrocerâmicas foram caracterizadas através das análises de difração de raios X (DRX), microscopia eletrônica de varredura (MEV), métodos de Arquimedes, microdureza e ensaio de flexão biaxial. Resultados: Os resultados de DRX mostraram predominantemente a fase de dissilicato de lítio para todos os tratamentos realizados. Além disso, grãos com forma agulhada foram mais predominantemente observados por MEV no grupo 3, assim como uma densificação maior e consequentemente valores maiores das propriedades mecânicas. Em contraste, o grupo 1 apresentou os menores valores de propriedades mecânicas e densificação, e também a maior porosidade. Conclusão: O presente estudo demonstrou como é extremamente importante seguir o tratamento térmico recomendado pelos fabricantes de cerâmica, incluindo tempo e temperatura, que possuem efeitos diretos na formação da fase cristalina, assim como na microestrutura do material e propriedades mecânicas. (AU)


Subject(s)
X-Ray Diffraction , Microscopy, Electron, Scanning , Crystallization
7.
Braz. dent. sci ; 24(2): 1-5, 2021. tab, ilus
Article in English | LILACS, BBO | ID: biblio-1177573

ABSTRACT

Objetives: this study aimed to fabricate electrospun-based polyetherimide (PEI) fibers, under controlled parameters, and to perform a diameter analysis for potential mechanical improvement of dental materials. Material and Methods: PEI pallets (0.75 g) were dissolved in 2 mL of chloroform and then processed by electrospinning, under a flow rate of 1mLh-1, three different electrical voltages (10kV, 15kV and 20kV) and three distances (10 cm, 15 cm and 18 cm) between the needle tip and collector. These parameter combinations resulted in nine experimental groups that were analyzed using scanning electron microscopy (SEM) and image processing program for diameter measurement. Statistical analysis was performed using two-way ANOVA with post-hoc Tukey (5% significance). Results: from SEM images it was possible to observe formation of solid, misaligned and flawless defect-free fibers. And from the statistical analysis, distance (p = 0,0026) and the electric tension (p = 0,0012) showed a significant difference, but not for interaction between then (p = 0,4486). Conclusion: thus, it can be concluded that there is a possibility of the morphology control of PEI electrospun fibers, such as diameter, that can be used for a variety of applications such as incorporation in dental materials in order to improve its properties. (AU)


Objetivos: o objetivo deste estudo foi fabricar fibras de polieterimida à base de eletrofiação (PEI), sob parâmetros controlados, e realizar uma análise de diâmetro para potencial aprimoramento mecânico de materiais odontológicos. Material e métodos: paletes de PEI (0,75 g) foram dissolvidos em 2 mL de clorofórmio e processados pela eletrofiação, sob uma razão de fluxo de 1 mLh-1, três tensões elétricas diferentes (10 kV, 15 kV e 20 kV) e três distâncias (10 cm, 15 cm e 18 cm) entre a ponta da agulha e o coletor. Essas combinações de parâmetros resultaram em nove grupos diferentes que foram analisadas usando microscopia eletrônica de varredura (MEV) e programa de processamento de imagem para medição de diâmetro. Resultados: a partir das imagens de MEV foi possível observar a formação de fibras sólidas, desalinhadas e sem defeitos. E a partir da análise estatística, a distância (p = 0,0026) e a tensão elétrica (p = 0,0012) apresentaram diferença significativa, mas não para interação entre elas (p = 0,4486). Conclusão: assim, pode-se concluir que existe a possibilidade de controle da morfologia das fibras eletrofiadas PEI, como o diâmetro, que pode ser utilizado para uma variedade de aplicações, como incorporação em materiais dentários, a fim de melhorar suas propriedades (AU)


Subject(s)
Polymers , Tensile Strength , Microscopy, Electron, Scanning , Dental Materials
8.
Braz. dent. sci ; 24(3): 1-7, 2021. tab, ilus
Article in English | LILACS, BBO | ID: biblio-1281904

ABSTRACT

Objective: The aim of the study was to fabricate and morphologically characterize ultrafine Polyetherimide fibers (PEI) associated with Polymethylmethacrylate (PMMA) ­ PP (group formed by the association of PEI with PMMA), produced by the electrospinning process. Material and Methods: A solution of PEI (0.562 g) + PMMA (0.377 g) dissolved in 2.5 mL of chloroform, 0.85 mL of Dimethylformamide (DMF) and 0.85 mL of 1.1.2.2 Tetrachloroethane (TCE) was prepared. For the electrospinning process, different continuous voltages (10 to 18 kV) and two different distances (8 and 12 cm) between the needle tip and the collecting apparatus were used, giving rise to 6 distinct groups of ultrafine fibers (PP 1 to 6) that were observed in Scanning Electron Microscopy to check for defects and calculate the average diameter of the fibers. Results: The best parameter, the parameter that was most effective for the production of fibers, observed was subjected to Energy Dispersion X-ray Spectroscopy (EDS), X-ray Diffraction (XRD) and Contact Angle Analysis tests. The data were analyzed using the ANOVA and Tukey test (p <0.05). From the comparative analysis of the pre-established parameters, the pattern of PP4 ultrafine fibers was shown to be more effective. Conclusion: The PP4 standard (13 kV ­ 12 cm) had an average diameter of 0.37 µm. An adequate parameter to electrospinning was able to produce ultrafine fibers of PMMA/PEI (AU)


Introdução: O objetivo do estudo foi sintetizar e caracterizar morfologicamente fibras ultrafinas de Polieterimida (PEI) associadas ao Polimetilmetacrilato (PMMA) - PP (grupo formado pela associação de PEI com PMMA), produzidas pelo processo de eletrofiação. Material e Métodos: Foi preparada uma solução de PEI (0,562 g) + PMMA (0,377 g) dissolvido em 2,5 mL de clorofórmio, 0,85 mL de Dimetilformamida (DMF) e 0,85 mL de 1.1.2.2 Tetracloroetano (TCE). Para o processo de eletrofiação, foram utilizadas diferentes tensões contínuas (10 a 18 kV) e duas distâncias diferentes (8 e 12 cm) entre a ponta da agulha e o aparelho coletor, dando origem a 6 grupos distintos de fibras ultrafinas (PP 1 a 6) que foram observados em Microscopia Eletrônica de Varredura para verificar defeitos e calcular o diâmetro médio das fibras. Resultados: O melhor parâmetro, o parâmetro mais eficaz para a produção de fibras, observado foi submetido aos testes de Espectroscopia de Dispersão de Energia (EDS), Difração de Raios X (DRX) e Análise do Ângulo de Contato. Os dados foram analisados pela ANOVA e teste de Tukey (p <0,05). A partir da análise comparativa dos parâmetros pré-estabelecidos, o padrão das fibras ultrafinas PP4 mostrou-se mais eficaz. Conclusão: O padrão PP4 (13 kV - 12 cm) apresentou diâmetro médio de 0,37 µm. Um parâmetro adequado para eletrofiação foi capaz de produzir fibras ultrafinas de PMMA / PEI. (AU)


Subject(s)
Microscopy, Electron, Scanning , Polymethyl Methacrylate , Spectroscopy, Electron Energy-Loss
9.
Braz. dent. sci ; 24(3): 1-9, 2021. tab, ilus
Article in English | LILACS, BBO | ID: biblio-1281947

ABSTRACT

Objective: This study was conducted to evaluate the shear bond strength (SBS) of resin composite on zirconia ceramic after different surface treatments and thermocycling. Material and Methods: Two hundred and seven zirconia specimens were divided into 9 groups and treated as follows: Group C­no treatment (served as the control); Group PC­Clearfil Ceramic primer (CP); Group PZ­Z-Prime Plus primer (ZP); Group A­sandblasted with 50 µm Al2O3 at 0.25 MPa for 20 s at a distance of 10 mm; Group AC­sandblasted and coated with CP; Group AZ­sandblasted and coated with ZP; Group L­GaAlAs diode laser with 808 ± 5 mm wavelength, 3 watts power, and 10 Hz frequency; Group LC­GaAlAs diode laser coated with CP; and Group LZ­GaAlAs diode laser coated with ZP. All specimens were directly bonded with a resin composite cylinder using Adper Scotchbond Multi-purpose. Specimens were stored at 37ºC for 30 days and subjected to 2,500 thermocycles from 5ºC and 55ºC before the SBS was performed. One-way ANOVA and Tukey's HSD test (α = 0.05) were performed. Surface topography changes were evaluated with a scanning electron microscope (SEM). Results:Sandblasting combined with CP or ZP (25.08 ± 0.86 and 24.78 ± 0.13 MPa, respectively) yielded the highest SBS and was significantly different from other methods (p < 0.05). SEM showed various degrees of changes depending on different surface treatments. Conclusion: Surface treatment by sandblasting combined with a CP or ZP significantly provide the highest SBS between zirconia and resin composite (AU)


Objetivo: Este estudo foi conduzido para avaliar a resistência ao cisalhamento (SBS) de resina composta em cerâmica de zircônia após diferentes tratamentos de superfície e termociclagem. Material e Métodos:Duzentos e sete espécimes de zircônia foram divididos em 9 grupos e tratados da seguinte forma: Grupo C­ sem tratamento (serviu como controle); Grupo PC­Clearfil Ceramic primer (CP); Grupo PZ­Z-Prime Plus primer (ZP); Grupo A - jateado com 50 µm de Al2O3 a 0,25 MPa por 20 s a uma distância de 10 mm; Grupo AC - jateado e revestido com CP; Grupo AZ - jateado e revestido com ZP; Grupo L ­ Laser de diodo GaAlAs com comprimento de onda de 808 ± 5 mm, potência de 3 watts e frequência de 10 Hz; Grupo LC ­Laser de diodo GaAlAs revestido com CP; e Grupo LZ ­ Laser de diodo GaAlAs revestido com ZP. Todos os espécimes foram diretamente colados com um cilindro de resina composta usando Adper Scotchbond Multi-purpose. As amostras foram armazenadas a 37ºC por 30 dias e submetidas a 2.500 termociclos de 5ºC e 55ºC antes da realização do SBS. ANOVA unilateral e teste HSD de Tukey (α = 0,05) foram realizados. As mudanças na topografia da superfície foram avaliadas com um microscópio eletrônico de varredura (MEV). Resultados:O jato de areia combinado com CP ou ZP (25,08 ± 0,86 e 24,78 ± 0,13 MPa, respectivamente) rendeu o maior SBS e foi significativamente diferente dos outros métodos (p < 0,05). SEM mostrou vários graus de mudanças dependendo dos diferentes tratamentos de superfície. Conclusão: O tratamento de superfície por jato de areia combinado com um CP ou ZP fornece significativamente o maior SBS entre a zircônia e a resina composta (AU)


Subject(s)
Microscopy, Electron, Scanning , Composite Resins , Shear Strength
10.
Braz. arch. biol. technol ; 64: e21190276, 2021. tab, graf
Article in English | LILACS | ID: biblio-1278448

ABSTRACT

Abstract The present study focused on the use of pineapple plant stem, which is an agro-waste, for the production of starch (11.08 % ± 0.77). Characters were studied using X-ray diffraction, nuclear magnetic resonance spectroscopy (NMR), fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and rheological methods. The granular size of stem starch was comparatively smaller than corn starch granules. The X-ray diffraction data revealed that stem starch has an A-type crystal structure. The molecular structure was similar to those obtained for native starches, which is confirmed by NMR and FTIR. The gelatinization temperature was observed to be higher than corn starch and rheological studies revealed; stem starch is more viscous than corn starch. The purity analysis showed that the harmful heavy metals were in negligible quantity and the tested pesticides were absent. This could make this a good source of starch for food industries. Results revealed that this agro-waste has a high potential for the production of good quality starch.


Subject(s)
Ananas , Agribusiness , Resistant Starch , Calorimetry, Differential Scanning/instrumentation , Microscopy, Electron, Scanning/instrumentation , Magnetic Resonance Spectroscopy/instrumentation , Spectroscopy, Fourier Transform Infrared/instrumentation
11.
J. appl. oral sci ; 29: e20200266, 2021. tab, graf
Article in English | LILACS | ID: biblio-1180799

ABSTRACT

Abstract Objectives We analyzed the effects of the Er:YAG laser used with different parameters on dentinal tubule (DT) occlusion, intrapulpal temperature and pulp tissue morphology in order to determine the optimal parameters for treating dentin hypersensitivity. Methodology Dentin specimens prepared from 36 extracted human third molars were randomized into six groups according to the treatment method (n=6 each): control (A); Gluma desensitizer (B); and Er:YAG laser treatment at 0.5 W , 167 J/cm2 (50 mJ, 10 Hz) (C), 1 W , 334 J/cm2 (50 mJ, 20 Hz) (D), 2 W , 668 J/cm2 (100 mJ, 20 Hz) (E), and 4 W and 1336 J/cm2 (200 mJ, 20 Hz) (F). Treatment-induced morphological changes of the dentin surfaces were assessed using scanning electron microscopy (SEM) to find parameters showing optimal dentin tubule occluding efficacy. To further verify the safety of these parameters (0.5 W, 167 J/cm2), intrapulpal temperature changes were recorded during laser irradiation, and morphological alterations of the dental pulp tissue were observed with an upright microscope. Results Er:YAG laser irradiation at 0.5 W (167 J/cm2) were found to be superior in DT occlusion, with an exposure rate significantly lower than those in the other groups (P<0.05). Intrapulpal temperature changes induced by Er:YAG laser irradiation at 0.5 W (167 J/cm2) with (G) and without (H) water and air cooling were demonstrated to be below the threshold. Also, no significant morphological alterations of the pulp and odontoblasts were observed after irradiation. Conclusion Therefore, 0.5 W (167 J/cm2) is a suitable parameter for Er:YAG laser to occlude DTs, and it is safe to the pulp tissue.


Subject(s)
Humans , Lasers, Solid-State/therapeutic use , Microscopy, Electron, Scanning , Dental Occlusion , Dentin
12.
J. appl. oral sci ; 29: e20200736, 2021. graf
Article in English | LILACS | ID: biblio-1180797

ABSTRACT

Abstract Objective To evaluate the efficacy of Nd:YAG laser associated with calcium-phosphate desensitizing pastes on dentin permeability and tubule occlusion after erosive/abrasive challenges. Methodology Dentin specimens were exposed to 17% ethylene diamine tetra-acetic acid (EDTA) solution for 5 min and randomly allocated into five groups: G1, control (no treatment); G2, Nd:YAG laser (1 W, 10 Hz, 100 mJ, 85 J/cm2); G3, Laser + TeethmateTM Desensitizer; G4, Laser + Desensibilize Nano P; and G5, Laser+Nupro®. Specimens underwent a 5-day erosion-abrasion cycling. Hydraulic conductance was measured post-EDTA, post-treatment, and post-cycling. Post-treatment and post-cycling permeability (%Lp) was calculated based on post-EDTA measurements, considered 100%. Open dentin tubules (ODT) were calculated at the abovementioned experimental moments using scanning electron microscopy and ImageJ software (n=10). Data were analyzed using two-way repeated measures ANOVA and Tukey's test (α=0.05). Results G1 presented the highest %Lp post-treatment of all groups (p<0.05), without significantly differences among them. At post-cycling, %Lp significantly decreased in G1, showed no significant differences from post-treatment in G3 and G4, and increased in G2 and G5, without significant differences from G1 (p>0.05). We found no significant differences in ODT among groups (p>0.05) post-EDTA. At post-treatment, treated groups did not differ from each other, but presented lower ODT than G1 (p<0.001). As for post-cycling, we verified no differences among groups (p>0.05), although ODT was significantly lower for all groups when compared to post-EDTA values (p<0.001). Conclusion All treatments effectively reduced dentin permeability and promoted tubule occlusion after application. Combining Nd YAG laser with calcium-phosphate pastes did not improve the laser effect. After erosive-abrasive challenges, treatments presented no differences when compared to the control.


Subject(s)
Lasers, Solid-State/therapeutic use , Dentin Desensitizing Agents , Microscopy, Electron, Scanning , Calcium/pharmacology , Dentin , Dentin Permeability
13.
J. appl. oral sci ; 29: e20200733, 2021. graf
Article in English | LILACS | ID: biblio-1154616

ABSTRACT

Abstract Enterococcus faecalis (E. faecalis), one of the main pathogens responsible for refractory periapical periodontitis and nosocomial infections, exhibits markedly higher pathogenicity in biofilms. Objectives Studies have shown that caseinolytic protease P (ClpP) is involved in biofilm formation. However, to date, few studies have investigated the role of ClpP in the survival of E. faecalis, and in enhancing biofilm formation. Therefore, we investigated the role of ClpP in the formation of E. faecalis biofilms. Methodology In our study, we used homologous recombination to construct clpP deleted and clpP complement strains of E. faecalis ATCC 29212. A viable colony counting method was used to analyze the growth patterns of E. faecalis. Crystal violet staining (CV) and confocal scanning laser microscopy (CLSM) were used to characterize biofilm mass formation and scanning electron microscopy (SEM) was used to observe the biofilm microstructure. Data was statistically analyzed via Student's t-test or one-way analysis of variance (ANOVA). Results The results exhibited altered growth patterns for the clpP deletion strains and depleted polysaccharide matrix, resulting in reduced biofilm formation capacity compared to the standard strains. Moreover, ClpP was observed to increase biofilm formation in E. faecalis. Conclusion Our study shows that ClpP can increase biofilm formation in E. faecalis and emphasizes the importance of ClpP as a potential target against E. faecalis.


Subject(s)
Humans , Enterococcus faecalis , Biofilms , Peptide Hydrolases , Virulence , Microscopy, Electron, Scanning , Microscopy, Confocal , Endopeptidase Clp
14.
Rev. Cient. CRO-RJ (Online) ; 5(3): 35-41, Dec. 2020.
Article in English | LILACS, BBO | ID: biblio-1342930

ABSTRACT

Introdução: o controle da qualidade no processo de fabricação dos instrumentos endodônticos é importante uma vez que defeitos e falhas superficiais podem comprometer o preparo dos canais. Objetivo: avaliar a presença de defeitos e falhas do processo de fabricação na superfície de instrumentos Reciproc (R25), Reciproc Blue (RB25) e XP-endo shaper (XP), por meio de microscopia eletrônica de varredura (MEV). Materiais e Métodos: Ao total, foram avaliados 60 instrumentos de níquel titânio, sendo 20 por grupo: R25, RB25 e XP, em três regiões: 0mm (ponta do instrumento), 4mm e 7mm da ponta, no MEV, com aumento de 100x. As imagens foram avaliadas quanto ao número de falhas de fabricação (bordo irregular, ranhura, microcavidade e rebarba) e por um sistema de escores de 1 a 4, sendo 1, nenhuma área com defeito e 4, mais de cinco áreas com defeitos na superfície. Os dados foram submetidos à análise estatística utilizando o teste de Dunn (p<0,05). Resultados: Sobre a análise por regiões, foram identificadas diferenças significativas em grande parte dos instrumentos. Comparando os diferentes instrumentos, não foi observada diferença significativa para microcavidade (p=0,76), bordo irregular (p=0,98) e rebarba (p=0,40). O instrumento R25 mostrou maior número de ranhuras em comparação aos demais (p=0,0000*). RB25 mostrou maiores valores de escores que os instrumentos R25 (p= 0,0002) eXP (p=0,01). Conclusão: Todos os instrumentos avaliados apresentaram defeitos/falhas superficiais do processo de fabricação.


Introduction: The quality control of endodontic instruments is extremely importantsince defects and failures on their surface, during their manufacturing process, can compromise the preparation of root canal. Objective: this study evaluated the presence of defects and failures in the manufacturing process on the surface of Reciproc (R25), Reciproc Blue (RB25) and XP endo-shaper (XP) instruments by means of scanning electron microscopy (SEM). Materials and Methods: In total, sixty nickel titanium instruments (n=20): R25, RB25 and XP were evaluated in the scanning electron microscope in three regions: 0mm (tip of the instrument), 4mmand 7mm of the tip, with a magnification of 100x. The images were evaluated in relation to the number of manufacturing faults (irregular border, groove, microcavity and burr) and by a system of scores, from 1 to 4, where 1 is no defective area and 4, more than five areas with defects on the surface. The data were submitted to statistical analysis using Kruskal-Wallis and Mann-Whitney tests (p<0.05). Results: Regarding the analysis by regions, significant differences were identified in most of the instruments. Comparing the different instruments, no significant difference was observed for microcavity (p=0.76), irregular border (p=0.98) and burr (p=0.40). The R25 instrument showed a greater number of grooves compared to the others (p=0.0000*). RB25 showed higher scores than the R25(p=0.0002) and XP (p=0.01) instruments. Conclusion: All evaluated instruments showed defects/failures in the manufacturing process.Introduction: The quality control of endodontic instruments is extremely importantsince defects and failures on their surface, during their manufacturing process, can compromise the preparation of root canal. Objective: this study evaluated the presence of defects and failures in the manufacturing process on the surface of Reciproc (R25), Reciproc Blue (RB25) and XP endo-shaper (XP) instruments by means of scanning electron microscopy (SEM). Materials and Methods: In total, sixty nickel titanium instruments (n=20): R25, RB25 and XP were evaluated in the scanning electron microscope in three regions: 0mm (tip of the instrument), 4mmand 7mm of the tip, with a magnification of 100x. The images were evaluated in relation to the number of manufacturing faults (irregular border, groove, microcavity and burr) and by a system of scores, from 1 to 4, where 1 is no defective area and 4, more than five areas with defects on the surface. The data were submitted to statistical analysis using Kruskal-Wallis and Mann-Whitney tests (p<0.05). Results: Regarding the analysis by regions, significant differences were identified in most of the instruments. Comparing the different instruments, no significant difference was observed for microcavity (p=0.76), irregular border (p=0.98) and burr (p=0.40). The R25 instrument showed a greater number of grooves compared to the others (p=0.0000*). RB25 showed higher scores than the R25(p=0.0002) and XP (p=0.01) instruments. Conclusion: All evaluated instruments showed defects/failures in the manufacturing process.


Subject(s)
Dental Instruments/standards , Endodontics/instrumentation , Microscopy, Electron, Scanning
15.
Dent. press endod ; 10(3): 69-74, Sept-Dec.2020. Tab, Ilus
Article in English | LILACS | ID: biblio-1348002

ABSTRACT

Objetivos: Avaliar três protocolos de irrigação final para remoção de detritos e material obturador de istmos simulados. Métodos: Setenta e oito pré-molares foram preparados com o sistema WaveOne Gold 45.05. Os dentes foram seccionados longitudinalmente e um istmo padronizado foi confeccionado no terço apical. Seis raízes foram utilizadas como controle negativo. Os espécimes foram randomizados em dois grupos principais (n=36). Trinta e seis raízes tiveram o istmo preenchido com detritos e as outras trinta e seis raízes foram obturadas com guta-percha e cimento endodôntico, por meio da técnica híbrida de Tagger. Cada grupo foi dividido em três subgrupos (n=12), de acordo com o protocolo de irrigação final: Easy Clean; irrigação ultrassônica passiva (PUI); e XP Clean. A ativação do NaOCl 2,5% pelo Easy Clean foi realizada em três ciclos de vinte segundos; e pelo XP Clean, por um minuto em movimento reciprocante e contínuo, respectivamente. No grupo PUI, o irrigante foi ativado em três períodos de vinte segundos. Resultados: Não foi encontrada associação entre os escores de remoção de detritos e os protocolos de irrigação (p=0,165). Foi observada associação entre os escores de remoção do material obturador e os protocolos de irrigação final (p<0,05). Conclusões: Os protocolos de irrigação final foram efetivos para a remoção de detritos, mas não para remoção de material obturador de istmos no terço apical (AU).


This study aimed to assess three final irrigation protocols on debris and filling removal from simulated irregularities. Methods: Seventy-eight mandibular premolars were prepared with WaveOne Gold system 45.05, splitted longitudinally, and a standardized groove was performed in the apical portion of the canals. Six roots served as negative control. The roots were randomly divided into two main groups (n = 36). The grooves were filled with dentin debris in thirty six roots. The others thirty-six were filled with gutta-percha and endodontic sealer using Tagger hybrid technique. Each main group was then divided into three groups (n = 12) according to the final irrigation protocol: Easy Clean, passive ultrasonic irrigation (PUI), and XP Clean. In Easy Clean 2.5% NaOCl activation was performed for 3 cycles of 20 seconds and XP Clean for one minute under reciprocating and continuous rotary motion and continuous rotary motion, respectively. In the PUI group, the irrigant was activated in three periods of 20 seconds. Results: No association was found among the scores of debris removal and the irrigation protocols (p = .165). An association was observed among the filling material removal scores and irrigation protocols (p< .05). Conclusion: Easy Clean, PUI and XP Clean were effective for dentin debris removal, but did not for filling material from artificial grooves in the apical third (AU).


Subject(s)
Bicuspid , Microscopy, Electron, Scanning , Efficacy , Lifting
16.
Int. j. morphol ; 38(6): 1779-1785, Dec. 2020. tab, graf
Article in English | LILACS | ID: biblio-1134511

ABSTRACT

SUMMARY: The Bactrian camel, which is native to China and Mongolia, is large in size and is an even-toed ungulate species. The double humps on the Bactrian camel back differentiate it from the dromedary camel, which has a single hump. This species has adapted to unsuitable conditions (lack of food and water) in the Gobi Desert and is advanced in unique anatomical and physiological characteristics during a prolonged evolution period. Several studies have been conducted on the anatomical features of the Bactrian camel, but none have given attention to the alveolar capillaries of the Bactrian camel lung. Therefore, the current study aims to explore the architecture of the alveolar capillary in the Bactrian camel lung and further explain the mechanism of blood flow in its lung. The current study extracted and examined the architecture of the alveolar capillary in the lung of the Bactrian camel (Camelus bactrianus) and further explained the mechanism of blood flow by performing lung casting and replica scanning electron microscopy methods. The reports showed that the resources of the alveolar-capillary originated from the capillaries of the subpleural space or interlobular septulum, sometimes originating from the precapillary arterioles or directly from the terminal arterioles. The alveolar capillaries anastomosed and formed a single layer of dense, basket-like network surrounding the alveolus. The mash diameter of the alveolar-capillary network was larger than that of the capillary, and the appearance of the mash was oval and elliptical. Many of the collapsed alveolar-capillary networks were found in the alveolar microvascular architecture in the lung of the Bactrian camel. The study found that, due to many collapsed alveoli in the Bactrian camel lung, the disproportional pressure between the pulmonary alveoli induced less imbalance of blood flow in the alveolar capillary, which affected the gas exchange efficiency. Therefore, the function of the anastomosing capillary branch was likely to regulate the blood flow between the alveolar-capillary network.


RESUMEN: El camello bactriano, es originario de China y Mongolia, es de gran tamaño y es una especie de ungulado de dedos pares. Las dobles jorobas del lomo del camello bactriano lo diferencian del dromedario, que tiene una sola joroba. Esta especie se ha adaptado a condiciones inadecuadas (falta de alimento y agua) en el desierto de Gobi y ha avanzado en características anatómicas y fisiológicas únicas durante un período de evolución prolongado. Se han realizado varios estudios sobre las características anatómicas del camello bactriano, pero ninguno ha prestado atención a los capilares alveolares del pulmón de este animal. Por lo tanto, el presente estudio tuvo como objetivo principal explorar la arquitectura del capilar alveolar en el pulmón del camello bactriano y explicar el mecanismo del flujo sanguíneo. A partir de nuestro trabajo se examinó la arquitectura del capilar alveolar en el pulmón del camello bactriano (Camelus bactrianus) mediante la realización de métodos de microscopía electrónica de barrido y escaneo pulmonar. Los informes mostraron que los recursos del alvéolo-capilar se originaban en los capilares del espacio subpleural o del tabique interlobulillar y a veces se originaban en las arteriolas precapilares o directamente en las arteriolas terminales. Los capilares alveolares se anastomosaban y formaban una densa red de capa única en forma de cesta que rodeaba el alvéolo. El diámetro del macerado de la red alveolar-capilar era mayor que el del capilar y el aspecto del macerado era ovalado y elíptico. Muchas de las redes alvéolo-capilares colapsadas se encontraron en la arquitectura microvascular alveolar en el pulmón del camello bactriano. El estudio encontró que, muchos alvéolos colapsados en el pulmón del camello bactriano, la presión desproporcionada entre los alvéolos pulmonares inducía un menor desequilibrio del flujo sanguíneo en el capilar alveolar, lo que afectaba la eficiencia del intercambio de gases. Por lo tanto, la función de la rama capilar anastomosante probablemente regularía el flujo sanguíneo entre la red alveolar-capilar.


Subject(s)
Animals , Pulmonary Alveoli/blood supply , Pulmonary Alveoli/ultrastructure , Capillaries/anatomy & histology , Capillaries/ultrastructure , Camelus/anatomy & histology , Lung/blood supply , Lung/ultrastructure , Microscopy, Electron, Scanning
17.
Rev. Odontol. Araçatuba (Impr.) ; 41(2): 52-57, maio-ago.2020. tab, ilus
Article in Portuguese | LILACS, BBO | ID: biblio-1102702

ABSTRACT

Objetivo: avaliar a adesão bacteriana do Streptococcus mutans na superfície de uma resina composta do tipo incremento único submetida a diferentes protocolos de polimento. Materiais e métodos: foram realizadas 60 amostras nas quais foram divididas aleatoriamente em 6 grupos (n=10) de diferentes tratamentos de superfície. Cinco amostras de cada grupo foram separadas e submetidas ao estudo de adesão bacteriana, das quais duas foram analisadas pela microscopia eletrônica de varredura. Foram contabilizadas as unidades formadoras de colônias UFC/ml de modo manual e realizada a média e desvio padrão de cada grupo. De acordo com os resultados analisados através do teste de One Way ANOVA e comparações múltiplas de Tukey observou-se uma diferença estatisticamente significativa entre os grupos. Resultados: os valores de UFC/ mL variaram de 0 para o grupo American Burrs a 8,64 para o grupo Dhpro. Os grupos Jota e Dhpro não diferiram estatisticamente entre si (p=0,71), porém diferiram dos demais grupos avaliados (p=0,45). Os grupos American Burrs e o controle negativo não diferiram estatisticamente entre si (p>0.999) e diferiram dos demais grupos testados (p=0,20). O grupo de controle positivo diferiu estatisticamente dos outros grupos (p=0,02) assim como o grupo KG (p=0,01). Conclusão: Diante dos resultados obtidos, pode-se concluir que, a superfície da resina Bulk Fill One submetida a diferentes protocolos de polimento e mesmo sem ter passado por nenhum tratamento de superfície é passível de adesão bacteriana seja por contagem manual ou microscopia eletrônica de varredura(AU)


Objective: To evaluate the bacterial adhesion of Streptococcus mutans on the surface of a single increment composite resin submitted to different polishing protocols. Materials and methods: 60 samples were randomly divided into 6 groups (n = 10) of different surface treatments. Five samples from each group were separated and submitted to the bacterial adhesion study, two of which were analyzed by scanning electron microscopy. The UFC/ml colony forming units were accounted for manually and the mean and standard deviation of each group were performed. According to the results analyzed by the One Way ANOVA test and Tukey's multiple comparisons, a statistically significant difference was observed between the groups. Results: The values ranged from 0 for the American Burrs group to 8.64 for the Dhpro group. The Jota and Dhpro groups did not differ statistically (p = 0.71), but differed from the other groups evaluated (p = 0.45). The American Burrs and negative control groups did not differ statistically (p> 0.999) and differed from the other groups tested (p = 0.20). The positive control group differed statistically from the other groups (p = 0.02) as did the KG group (p = 0.01). Conclusion: It can be concluded that the surface of the Bulk Fill One resin submitted to different polishing protocols and even without any surface treatment is susceptible to bacterial adhesion either by manual counting or scanning electron microscopy(AU)


Subject(s)
Streptococcus mutans , Bacterial Adhesion , Composite Resins , Resins, Synthetic , Microscopy, Electron, Scanning
19.
Ortodoncia ; 84(167): 26-34, jun. 2020. ilus, tab
Article in Spanish | LILACS | ID: biblio-1147572

ABSTRACT

Los alambres en ortodoncia son elementos activos que tienen la capacidad de almacenar energía y liberar fuerzas. Los brackets permiten la unión directa y selectiva entre el arco de alambre y las piezas dentarias, lo que optimiza el efecto de presiones específicas de forma precisa y controlada, transmitiendo el movimiento en los tres sentidos del espacio. Durante el tratamiento de ortodoncia, estos elementos podrían sufrir alteraciones estructurales impidiendo el movimiento dental óptimo. En el presente trabajo de investigación, se analizó la respuesta que tienen el arco de acero inoxidable 0.019" × 0.025" y el slot de brackets de zafiro, en el sector anterior del maxilar superior, cuando ejercen fricción entre sí, antes y después de ser utilizados clínicamente en un tratamiento de ortodoncia. Para esto, las muestras fueron lavadas con alcohol absoluto al 96 % y secadas para ser observadas en el microscopio electrónico de barrido ambiental (MEB) (ESEM - environmental scanning electron microscope), modelo FEI ESEM QuantaTM 200. Los arcos rectangulares fueron analizados por sus cuatro caras y cuatro aristas (superior, inferior, interna y externa; respectivamente) y los slots de brackets de zafiro fueron observados en un corte sagital y dividido en forma lineal en tres mediciones (interna, media y externa). Los datos obtenidos fueron volcados en una planilla de tabulación de datos para su análisis estadístico, mediante el test de normalidad de Shapiro-Wilk para medidas no paramétricas y el test de Fisher. En conclusión, las zonas más afectadas por el desgaste fueron las caras y aristas internas del arco de acero de 0.019" × 0.025", y la medición interna del slot de brackets de zafiro. Ambas presentaban una pérdida de la solución de continuidad en su estructura, evidenciando un área de mayor fricción(AU)


Orthodontic wires are active elements that have the ability to store energy and release forces. The brackets allow the direct and selective bonding between the wire arch and teeth, optimizing the effect of specific pressures in a precise and controlled way, transmitting movement in the three directions of space. During orthodontic treatment, these elements could undergo structural changes preventing optimal dental movement. In the current research work, the response that the 0.019" × 0.025" stainless steel archwire and the sapphire bracket slot have in the anterior sector of the upper jaw when they exert friction on each other, before and after being clinically used in an orthodontic treatment was analyzed. For this purpose, the samples were washed in 96% absolute alcohol and dried to be observed under the environmental scanning electron microscope ESEM (MEB - microscopio electrónico de barrido ambiental), model FEI ESEM QuantaTM 200. The rectangular archwires were analyzed on their 4 faces and 4 edges (upper, lower, internal and external) and the sapphire brackets slots were observed in a sagittal section and linearly divided into three measurements (internal, medium and external). The data obtained were put in a data tabulation spreadsheet for its statistical analysis by using the Shapiro-Wilk normality test for nonparametric measures, and the Fisher test. In conclusion, the areas most affected by wear were the internal face and edges of the 0.019" × 0.025" steel arch and the internal measurement of the sapphire brackets slot. They both presented loss of continuity in their structure, providing evidence of an area of greater friction(AU)


Subject(s)
Orthodontic Wires , Stainless Steel , Microscopy, Electron, Scanning , Orthodontic Brackets , Friction , Interrelation
20.
Int. j. morphol ; 38(3): 602-610, June 2020. graf
Article in English | LILACS | ID: biblio-1098294

ABSTRACT

Due to the great change in the morphology of squamate vomeronasal organ (VNO), the histomorphology characteristics of VNO in Scincella tsinlingensis were studied by light and electronic microscopy. The results indicated that the VNO of S. tsinlingensis was located at the base of nasal cavity and consisted of a mushroom body situated anteroventrally and a sensory epithelium (SE) situated dorsocaudally. SE was composed of supporting cells, receptor cells and basal cells, and the supporting cells contained secretory granules near the surface membrane. Most of receptor cells were irregular in shape with long cytoplasmic extensions and characterized by microtubules, vesicles, and mitochondria. The basal cells with long cytoplasmic extensions were also irregular in shape and appeared a greater electron density than others. The thick nerve bundles were found on the dorsomedial area of VNO, and the surface of mushroom body was non-sensory epithelium consisting of ciliated and basal cells, without goblet cells. Epithelial cells were arranged in irregular, with many cilia and microvilli distributed on its free surface. Cells on the basal layer were irregularly circular in shape and arranged sparsely. Taken together, the results indicated that the fine structure of VNO in S. tsinlingensis was similar to other species from scincomorphs.


Debido al gran cambio en la morfología del órgano vomeronasal (OVN), se estudiaron las características histomorfológicas en la Scincella tsinlingensis por microscopías de luz y electrónica. Los resultados indicaron que el OVN de S. tsinlingensis se localizaba en la base de la cavidad nasal y consistía en un cuerpo como hongo situado anteroventralmente y un epitelio sensorial (ES) situado dorso caudamente. El ES estaba compuesto de células de soporte, células receptoras y células basales, y las células de soporte contenían gránulos secretores cerca de la membrana superficial. En gran parte de la mayoría de las células receptoras se observó una forma irregular con largas extensiones citoplasmáticas, caracterizadas por microtúbulos, vesículas y mitocondrias. Las células basales con extensiones citoplasmáticas también tenían forma irregular y algunas parecían tener una mayor densidad de electrones. Los haces gruesos nerviosos se encontraron en el área dorsomedial del OVN, la superficie del cuerpo de estaba compuesto de epitelio no sensorial y consistía de células ciliadas y basales, sin células caliciformes. Las células epiteliales estaban dispuestas de manera irregular, con muchos cilios y microvellosidades distribuidas en su superficie libre. Las células en la capa basal eran escasas y de forma circular irregular. Tomados en conjunto, los resultados indicaron que la estructura fina del OVN en S. tsinlingensis era similar a otras especies de scincomorpha.


Subject(s)
Animals , Vomeronasal Organ/anatomy & histology , Lizards/anatomy & histology , Microscopy, Electron, Scanning , Vomeronasal Organ/ultrastructure , Microscopy, Electron, Transmission
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