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1.
Polymers (Basel) ; 15(16)2023 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-37631453

RESUMO

This study evaluated the bonding characteristics of a silane coupling agent (SCA) and a methyl methacrylate (MMA)-containing primer (MCP) for 11 types of commercial composite blocks (CBs) for sandblasted and non-sandblasted surfaces. The shear bond strength (SBS) was measured according to ISO 29022: Notched-edge shear bond strength test. The SBS results demonstrated statistically significant differences between the CBs under all identical conditions. For the non-sandblasted groups, the SBSs of MCP-treated specimens were significantly higher than those of SCA-treated specimens for all but two CBs. Comparing the two treatments in sandblasted groups, the SBS was significantly higher for seven out of 11 MCP-treated RCB specimens, in contrast with three cases for the SCA-treated group. Two-way ANOVA for SBS showed the interaction effect between sandblasting and primer type for specific CBs, indicating that the sandblasting treatment improved SBS more effectively for SCA-treated specimens. Moreover, the effect of the SCA treatment was more material-dependent compared to that of the MCP treatment, which did not achieve a strong bond in all CBs but proved more effective than the SCA treatment, especially for non-sandblasted surfaces.

2.
Cureus ; 14(3): e23574, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35371893

RESUMO

BACKGROUND: Evaluation of adhesion of Streptococcus mutans on recycled orthodontic brackets is significant, as Streptococcus mutans is the main causative factor in enamel demineralization and many clinicians, in their practice, resort to reconditioning of brackets, as it is cost-effective. Thus, this study aimed to evaluate and compare the adhesion of Streptococcus mutans on new brackets of three different companies (Group I, Group II, and Group III) and brackets recycled by three different recycling methods (RC I: flame heating followed by acid bath; RC II: flame heating followed by ultrasonic cleaning and electropolishing; RC III: flame heating followed by sandblasting and electropolishing). Materials and methods: A total of 10 brackets from each group were incubated with 108 colony-forming units (CFUs) of Streptococcus mutans in trypticase soy broth overnight. The brackets were then washed with phosphate-buffered saline and treated with 0.25% trypsin for 20 minutes followed by vertexing the solution to remove the adhered bacteria and then the solution was plated on the blood agar and incubated overnight. The total viable count of bacteria was quantified. RESULTS: Comparing all the three groups and recycling methods, Group II brackets showed significantly more adhesion, Group I brackets showed lesser adhesion, and Group III brackets showed intermediate adhesion. When comparing recycling methods, all the three methods of recycling with all the three groups showed more bacterial adhesion than the control brackets, which was statistically insignificant (P > 0.05). CONCLUSION: Recycled brackets showed more bacterial adhesion and electropolishing resulted in reduced bacterial adhesion.

3.
Folia Med (Plovdiv) ; 64(6): 938-944, 2022 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-36876573

RESUMO

AIM: Clinicians and researchers have always made every effort to achieve proper bonding between the surface of the tooth and the rebonded orthodontic brackets in order to prevent the re-fracture failure of orthodontic pressures throughout treatment. The aim of this study was to determine the bond strength of rebonded brackets by four adhesive removal methods.


Assuntos
Braquetes Ortodônticos , Projetos de Pesquisa , Pressão , Resistência ao Cisalhamento
4.
Micromachines (Basel) ; 12(10)2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34683213

RESUMO

Powerful sunlight, a high water temperature, and stagnation in the water flow induce eutrophication in rivers and lakes, which destroys the aquatic ecosystem and threatens the downstream water supply systems. Accordingly, it is very important to perform real-time measurements of nutrients that induce algal growth, especially total phosphorus, to preserve and manage the aquatic ecosystem. To conduct quantitative analysis of the total phosphorus in the aquatic ecosystem, it is essential to perform a pretreatment process and quickly separate the phosphorus, combined with organic and inorganic materials, into a phosphate. In this study, the sandblasting process was used for the physical etching of the wafer, and photocatalytic materials were deposited on the surface with various roughness in order to improve the photocatalytic reaction surface and efficiency. The photocatalytic reaction was applied to combine the pretreated sample with the coloring agent for color development, and the absorbance of the colored sample was analyzed quantitatively to compare and evaluate the characteristics, followed by the surface increase in the photocatalytic materials. In addition, the pretreatment and measurement parts were materialized in a single chip to produce a small and light total phosphorus analysis sensor.

5.
Braz. dent. sci ; 24(4): 1-11, 2021. tab, ilus
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-1293054

RESUMO

Objective: The present study was oriented to estimate the effect of different surface treatments on the microleakage between the soft liner and acrylic with and without the use of autoclave as disinfection method. Material and Methods: Sixty samples were split into two groups: the autoclaved groups and non-autoclaved groups. Each one subdivided into three groups: first one without any treatments as a control group; in the second group surface of the samples were treated with CO2 laser (10.6 nm wavelength for 15 seconds), and in the third group the surface was treated with sandblasting (250 µm Al2O3). All the samples exposed to thermocycling, then the microleakage test was evaluated by gauging dye penetration depth between the soft liner and acrylic disc using a digital microscope. Data analyzed statistically by One-way ANOVA and Tukey's post-hoc tests. In addition, t-test was used for comparison between two groups (P-value ≤ 0.05). Results: The maximum mean values for the microleakage were observed in the untreated group (control) followed by the group treated by CO2 laser and the lowest mean value of microleakage was related to the third group for both non-autoclaved and autoclaved groups with significant differences among them. In addition, depending on the use of autoclave, there was non-significant in all studied groups. Conclusions: There was a decrease in the microleakage when the surface treated with CO2laser and sandblast. The use of autoclave did not badly change the microleakage between the soft liner and denture base. (AU)


Objetivo: O presente estudo teve como objetivo estimar o efeito de diferentes tratamentos de superfície na microinfiltração entre o soft liner e o acrílico usando ou não a autoclve como método de desinfecção. Material e Métodos: Sessenta amostras foram divididas em dois grupos: grupo com uso da autoclave e grupo sem uso da autoclave. Cada um subdivide em três grupos: o primeiro sem nenhum tratamento como grupo controle; no segundo grupo, a superfície das amostras foi tratada com laser de CO2 (comprimento de onda de 10,6 nm por 15 segundos) e, no terceiro grupo, a superfície foi tratada com jateamento (250 µm Al2O3). Todas as amostras foram expostas à termociclagem, em seguida o teste de microinfiltração foi realizado medindo-se a profundidade de penetração do corante entre o soft liner e o disco de acrílico em microscópio digital. Os dados foram analisados estatisticamente por One-way ANOVA e testes post-hoc de Tukey. Além disso, o teste t foi usado para comparação entre dois grupos (P-valor ≤ 0,05). Resultados: Os valores médios máximos de microinfiltração foram observados no grupo não tratado (controle) seguido pelo grupo tratado com laser de CO2 e o valor médio mínimo de microinfiltração foi relacionado ao terceiro grupo para ambos os grupos não autoclavado e autoclavado com diferenças significativas entre eles. Além disso, dependendo do uso de autoclave, não houve significância em todos os grupos estudados. Conclusão: Houve diminuição da microinfiltração quando a superfície foi tratada com laser de CO2e jateamento. O uso de autoclave não alterou a microinfiltração entre o soft liner e a base da prótese (AU)


Assuntos
Abrasão Dental por Ar , Reembasadores de Dentadura , Lasers de Gás
6.
Dent Mater J ; 39(2): 262-271, 2020 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-31723095

RESUMO

The aim of this paper is to study changes in the Ag-Pd-Cu-Au alloy surfaces by alumina air-abrasion process and effect of those changes on the adhesive bonding characteristic. Surface roughness, surface composition and chemical state of the alumina air-abraded alloys were analyzed by a confocal laser scanning microscope, an energy dispersive X-ray spectroscopy and an X-ray photoelectron spectroscopy. The results showed that the alumina air-abrasion changed the alloy surface by mechanical roughening, alumina remain and copper oxidation. Effect of the changes in the alloy surface on the adhesive bonding characteristic was examined by using a methyl methacrylate/tri-n-butylborane derivative (MMA/TBB) resin cement with the 10-methacryloyloxydecyl dihydrogen phosphate (MDP) contained primer. The shear bond strength test results indicated that the surface oxidation by the abrasion is the main contributor that improved the adhesive bonding rather than other effects such as mechanical roughening or alumina remain.


Assuntos
Óxido de Alumínio , Colagem Dentária , Ligas Dentárias , Cimentos Dentários , Teste de Materiais , Metacrilatos , Cimentos de Resina , Resistência ao Cisalhamento , Propriedades de Superfície
7.
Dent Mater J ; 38(4): 630-637, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-30971652

RESUMO

The goal of this study was to investigate the chemical alteration of a dental alloy surface by alumina air-abrasion and its effect on bonding to resin cement. Alumina air-abrasion was carried out on an Ag-Pd-Cu-Au alloy. The surface morphology and chemical state of the abraded alloy were characterized. The effect of the air-abrasion on the shear bond strength between the alloy and a methyl methacrylate/tri-n-butyl borane (MMA/TBB) resin cement with some primers was evaluated. The surface characterization revealed that the alumina air-abrasion mechanically roughened and chemically altered the surface. The chemical alterations had two effects: (1) abraded alumina particles remained on the alloy surface and (2) copper ions were oxidized in the alloy surface. As the result, the shear bond strength test indicated that 10-methacryloyloxydecyl dihydrogen phosphate (MDP) contained primer worked with the abraded alloy surface, whereas it did not work with the non-abraded alloy surface.


Assuntos
Colagem Dentária , Cimentos de Resina , Óxido de Alumínio , Ligas Dentárias , Análise do Estresse Dentário , Teste de Materiais , Resistência ao Cisalhamento , Propriedades de Superfície
8.
J Contemp Dent Pract ; 18(6): 443-447, 2017 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-28621271

RESUMO

AIM: Surface treatment is necessarily required for bonding of zirconia to the veneering porcelain and luting cements. Sandblasting is the most common and probably the most efficient surface treatment method. Sandblasting roughens the surface and may affect the flexural strength of zirconia. Different sandblasting protocols may yield variable results. This study sought to assess the effect of sandblasting angle and distance on the biaxial flexural strength of zirconia-based ceramics. MATERIALS AND METHODS: This in vitro experimental study was conducted on 50 zirconia discs measuring 1.2 ± 0.2 mm in thickness and 15 ± 0.2 mm in diameter, which were randomly divided into five groups (n = 10) of one control and four experimental groups subjected to sandblasting with 110 µm aluminum oxide particles under 2 bar pressure for 10 seconds at 15 and 25 mm distances and 45 and 90° angles (between the nozzle head and zirconia surface). Surface roughness was measured by a roughness tester and samples were subjected to thermocycling followed by biaxial flexural strength testing according to ISO6872. The data were analyzed using one-way analysis of variance (p < 0.05). RESULTS: No statistically significant difference was noted in the mean biaxial flexural strength of the five groups (p = 0.40). Different sandblasting protocols yielded significantly different surface roughness values (p < 0.001). The highest and the lowest mean surface roughness belonged to 15 mm/90° (0.51 µm) and control (0.001 µm) groups respectively. CONCLUSION: Change in sandblasting angle and distance had no significant effect on the biaxial flexural strength of zirconia-based ceramic, but surface roughness was significantly different in the study groups. Clinical significances: Regardless of sandblasting angle, increasing distance to 25 mm significantly decreases surface roughness that may negatively affect zirconia bond strength.


Assuntos
Cimentos Dentários/química , Corrosão Dentária/métodos , Facetas Dentárias , Zircônio/química , Colagem Dentária , Porcelana Dentária , Humanos , Teste de Materiais , Propriedades de Superfície
9.
Mater Sci Eng C Mater Biol Appl ; 78: 1187-1194, 2017 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-28575956

RESUMO

Sandblast and acid-etching (SLA) is the most prevalent treatment to titanium implants, while residual sand particles are inevitably introduced on SLA titanium surfaces. NH4OH and H2O2 mixture was used to etch titanium plates (E) and titanium bars (EB), aiming at substituting sandblast procedure. To study the effects of different scale rough structures on cell response of Human osteoblast-like cells (MG63), traditional H2SO4 and HCl mixture was also used to further etch the titanium plates above (DE). Holes of 10-20µm were obtained on E and DE surfaces, which are very close to the size of osteoblasts. Surfaces with micro/nano and micro/submicro hierarchical structures were obtained on the treated titanium. As-prepared E, DE and EB surfaces are hydrophilic, while only EB stayed hydrophilic after 5days' exposure to air. MG63 cultured on E and EB surfaces showed higher proliferation rate and attachment area than on DE and P surfaces. E and DE showed higher alkaline phosphatases (ALP) activity after 7 and 14days of osteoinduction, while EB showed the highest osteopontin (OPN) and bone sialoprotein (BSP) production after 21days of osteoinduction. These results indicate that E and EB surfaces boost the proliferation and osteogenic differentiation of MG63 without introducing sand particles. This is a promising treatment to titanium implant.


Assuntos
Titânio/química , Fosfatase Alcalina , Diferenciação Celular , Proliferação de Células , Humanos , Peróxido de Hidrogênio , Osteoblastos , Osteogênese , Propriedades de Superfície
10.
J Adv Prosthodont ; 9(1): 38-44, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28243390

RESUMO

PURPOSE: The objective of this study was to investigate the effect of surface treatments on microtensile bond strengths (MTBSs) of two types of indirect resin composites bonded to a conventional direct resin composite. MATERIALS AND METHODS: Indirect resin composite blocks of Ceramage and SR Nexco were prepared in a plastic mold having a dimension of 10 × 10 × 4 mm. These composite blocks were divided into three groups according to their surface treatments: Group1: Sandblast (SB); Group2: Sandblast and ultrasonically clean (SB+UL); Group3: Sandblast plus silane (SB+SI). After bonding with direct resin composite, indirect-direct resin composite blocks were kept in distilled water for 24 hours at 37℃ and cut into microbars with the dimension of 1 × 1 × 8 mm. Microbar specimens (n = 40 per group) were loaded using a universal testing machine. Failure modes and compositions were evaluated by SEM. The statistical analyses of MTBS were performed by two-way ANOVA and Dunnett's test at α = .05. RESULTS: Surface treatments and brands had effects on the MTBS without an interaction between these two factors. For SR Nexco, the MTBSs of SB and SB+SI group were significantly higher than that of SB+UL. For Ceramage, the MTBSs of SB and SB+SI were significantly higher than that of SB+UL. The mean MTBS of the Ceramage specimens was significantly higher than that of SR Nexco for all surface treatments. CONCLUSION: Sandblasting with or without silane application could improve the bond strengths of repaired indirect resin composites to a conventional direct resin composite.

11.
Dent Mater ; 33(3): e124-e135, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28057347

RESUMO

OBJECTIVE: CAD-CAM blocks to fabricate semi-direct and indirect restorations are available in different sorts of ceramics as well as composite. In order to bond restorations prepared out of composite blocks into tooth cavities, it is recommended to gently sandblast the surface prior to the application of a primer/adhesive. Today, the effect of sandblasting composite block surfaces has not thoroughly been investigated. In this study, the ultra-structure of composite CAD-CAM blocks was investigated with special attention to the effect of sandblasting on the surface topography and of silanization on the bonding performance. METHODS: Five different composite CAD-CAM blocks were involved. We correlatively investigated their structural and chemical composition using X-ray diffraction (XRD), energy dispersion spectroscopy (EDS), scanning electron microscopy (SEM) and (scanning) transmission electron microscopy ((S)TEM). The effect of sandblasting was also imaged in cross-section and at the interface with composite cement. Finally, we measured the shear bond strength to the sandblasted block surface with and without silanization. RESULTS: All composite blocks revealed a different ultra-structure. Sandblasting increased surface roughness and resulted in an irregular surface with some filler exposure. Sandblasting also damaged the surface. When the sandblasted composite blocks were silanized, superior bonding receptiveness in terms of higher bond strength was achieved except for Shofu Block HC. SIGNIFICANCE: Sandblasting followed by silanization improved the bond strength to composite CAD-CAM blocks. However, sandblasting may also damage the composite CAD-CAM block surface. For the composite CAD-CAM block Shofu Block HC, the damage was so severe that silanization did not improve bond strength.


Assuntos
Resinas Compostas , Desenho Assistido por Computador , Cimentos de Resina , Colagem Dentária , Teste de Materiais , Silanos , Propriedades de Superfície
12.
Artigo em Inglês | WPRIM (Pacífico Ocidental) | ID: wpr-107070

RESUMO

PURPOSE: The objective of this study was to investigate the effect of surface treatments on microtensile bond strengths (MTBSs) of two types of indirect resin composites bonded to a conventional direct resin composite. MATERIALS AND METHODS: Indirect resin composite blocks of Ceramage and SR Nexco were prepared in a plastic mold having a dimension of 10 × 10 × 4 mm. These composite blocks were divided into three groups according to their surface treatments: Group1: Sandblast (SB); Group2: Sandblast and ultrasonically clean (SB+UL); Group3: Sandblast plus silane (SB+SI). After bonding with direct resin composite, indirect-direct resin composite blocks were kept in distilled water for 24 hours at 37℃ and cut into microbars with the dimension of 1 × 1 × 8 mm. Microbar specimens (n = 40 per group) were loaded using a universal testing machine. Failure modes and compositions were evaluated by SEM. The statistical analyses of MTBS were performed by two-way ANOVA and Dunnett's test at α = .05. RESULTS: Surface treatments and brands had effects on the MTBS without an interaction between these two factors. For SR Nexco, the MTBSs of SB and SB+SI group were significantly higher than that of SB+UL. For Ceramage, the MTBSs of SB and SB+SI were significantly higher than that of SB+UL. The mean MTBS of the Ceramage specimens was significantly higher than that of SR Nexco for all surface treatments. CONCLUSION: Sandblasting with or without silane application could improve the bond strengths of repaired indirect resin composites to a conventional direct resin composite.


Assuntos
Fungos , Plásticos , Ultrassom , Água
13.
J Prosthodont Res ; 60(4): 289-293, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26948430

RESUMO

PURPOSE: Zirconia exhibits excellent strength and high biocompatibility in technological applications and it is has therefore been investigated for clinical applications and research. Before setting prostheses, a crown prosthesis inner surface is sandblasted with alumina to remove contaminants and form small cavities. This alumina sandblasting causes stress-induced phase transition of zirconia. Atmospheric-pressure low-temperature plasma has been applied in the dental industry, particularly for adhesives, as a surface treatment to activate the surface energy and remove contaminants. The purpose of this study was to examine the influence of atmospheric-pressure low-temperature plasma treatment on the shear bond strength between zirconia and adhesive resin cement. METHODS: The surface treatment method was classified into three groups: untreated (Cont group), alumina sandblast treatment (Sb group), and atmospheric-pressure low-temperature plasma treatment (Ps group). Adhesive resin cement was applied to stainless steel and bonded to zirconia. Shear adhesion tests were performed after complete hardening of the cement. Multiple comparisons were performed using a one-way analysis of variance and the Bonferroni method. X-ray diffractometry was used to examine the change in zirconia crystal structure. RESULTS: Statistically significant differences were noted between the control and Sb groups and between the control and Ps groups. In contrast, no statistically significant differences were noted for the Ps and Sb bond strength. Atmospheric-pressure low-temperature plasma treatment did not affect the zirconia crystal structure. CONCLUSIONS: Atmospheric-pressure low-temperature plasma treatment improves the bonding strength of adhesive resin cement as effectively as alumina sandblasting, and does not alter the zirconia crystal structure.


Assuntos
Pressão Atmosférica , Temperatura Baixa , Colagem Dentária , Cimentos Dentários , Materiais Dentários , Plasma , Cimentos de Resina , Resistência ao Cisalhamento , Temperatura , Zircônio , Óxido de Alumínio , Cristalização , Cristalografia por Raios X , Teste de Materiais , Transição de Fase , Zircônio/química
14.
Acta Biomater ; 35: 305-17, 2016 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-26861855

RESUMO

A polyetheretherketone (PEEK) surface was modified using a sol-gel-derived TiO2 coating in order to confer bone-bonding ability. To enhance the bonding strength of the coating layer, pretreatment with either O2 plasma or sandblasting was performed prior to sol-gel coating. Additionally, post-treatment with acid was carried out to confer apatite (calcium phosphate)-forming ability to the surface. Biomechanical and histological analyses performed using an in vivo rabbit tibia model showed that PEEK surfaces modified with sol-gel-derived TiO2 and acid post-treatment had better bone-bonding properties than uncoated PEEK surfaces. These modified surfaces also performed well in terms of their in vitro cell responses due to their modified surface chemistries and topographies. Although O2 plasma or sandblasting treatment were, for the most part, equivocal in terms of performance, we conclude that sol-gel-derived TiO2 coating followed by acid post-treatment significantly improves the bone bonding ability of PEEK surfaces, thus rendering them optimal for their use in surgical implants. STATEMENT OF SIGNIFICANCE: The role of polyetheretherketone (PEEK) as an alternative biomaterial to conventional metallic implant materials has become increasingly important. However, its low bone bonding ability is yet to be resolved. This in vivo and in vitro investigation on the functionalization of PEEK surfaces highlights the utility of this material in clinical interventions that require implants, and may extend range of applications of PEEK.


Assuntos
Materiais Revestidos Biocompatíveis/farmacologia , Cetonas/farmacologia , Transição de Fase , Polietilenoglicóis/farmacologia , Titânio/farmacologia , Fosfatase Alcalina/metabolismo , Animais , Benzofenonas , Fenômenos Biomecânicos/efeitos dos fármacos , Adesão Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Masculino , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Osteogênese/genética , Fenótipo , Polímeros , Próteses e Implantes , Coelhos , Propriedades de Superfície , Microtomografia por Raio-X
15.
Micromachines (Basel) ; 7(3)2016 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-30407424

RESUMO

This paper presents processes for glass micromachining, including sandblast, wet etching, reactive ion etching (RIE), and glass reflow techniques. The advantages as well as disadvantages of each method are presented and discussed in light of the experiments. Sandblast and wet etching techniques are simple processes but face difficulties in small and high-aspect-ratio structures. A sandblasted 2 cm × 2 cm Tempax glass wafer with an etching depth of approximately 150 µm is demonstrated. The Tempax glass structure with an etching depth and sides of approximately 20 µm was observed via the wet etching process. The most important aspect of this work was to develop RIE and glass reflow techniques. The current challenges of these methods are addressed here. Deep Tempax glass pillars having a smooth surface, vertical shapes, and a high aspect ratio of 10 with 1-µm-diameter glass pillars, a 2-µm pitch, and a 10-µm etched depth were achieved via the RIE technique. Through-silicon wafer interconnects, embedded inside the Tempax glass, are successfully demonstrated via the glass reflow technique. Glass reflow into large cavities (larger than 100 µm), a micro-trench (0.8-µm wide trench), and a micro-capillary (1-µm diameter) are investigated. An additional optimization of process flow was performed for glass penetration into micro-scale patterns.

16.
J Artif Organs ; 19(2): 121-7, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26526561

RESUMO

The aim of this study was to evaluate flow from a new dispersive aortic cannula (Stealthflow) in the aortic arch using flow visualization methods. Particle image velocimetry was used to analyze flow dynamics in the mock aortic model. Flow patterns, velocity distribution, and streamlines with different shape cannulas were evaluated in a glass aortic arch model. We compared flow parameters in two different dispersive type cannulas: the Stealthflow and the Soft-flow cannula. A large vortex and regurgitant flow were observed in the aortic arch with both cannulas. With the Stealthflow cannula, a high-velocity area with a maximum velocity of 0.68 m/s appeared on the ostium of the cannula in the longitudinal plane. With the Soft-flow cannula, 'multiple jet streams, each with a velocity less than 0.60 m/s, were observed at the cannula outlet. Regurgitant flow from the cannula to the brachiocephalic artery and to the ascending aorta on the greater curvature was specific to the Soft-flow cannula. The degree of regurgitation on the same site was lower with the Stealthflow cannula than with the Soft-flow cannula. The Stealthflow cannula has similar flow properties to those of the Soft-flow cannula according to glass aortic model analysis. It generates gentle flow in the aortic arch and slow flow around the ostia of the aortic arch vessels. The Stealthflow cannula is as effective as the Soft-flow cannula. Care must be taken when the patient has thick atheromatous plaque or frail atheroma on the lesser curvature of the aortic arch.


Assuntos
Aorta Torácica/fisiologia , Cânula , Modelos Cardiovasculares , Aorta , Velocidade do Fluxo Sanguíneo , Tronco Braquiocefálico , Embolia de Colesterol/prevenção & controle , Humanos , Hidrodinâmica , Reologia
17.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-678854

RESUMO

Objective: To study whether the bond strength between enamel and composite resin could be enhanced by intraoral sand abrasive. Methods: Ten human maxillary first incisior teeth were divided into 2 groups The experimental group was sandblasted with 30 ?m Al 2O 3 (CoJet Sand, pressure 300 kPa) from a distance of 5 mm for 5 seconds, and the control group were not sandblasted. The Herculite composite resin composite cylinders were bonded with Coltene system. Bonded specimens were stored in 37 ℃ distilled water for 24 h, then were subjected to shear force in a testing machine Stress at failure was calculated in Mpa, and mode of failure was recorded. The Student t test was applied to the data. Results: The shear bond strength of experimental groups was (33.0?1.8) MPa , and that of control groups was (26.7?5.2) MPa ,there was significant difference between these two groups. All the adhesive failures happened at the enamel composite resin interface , except that cohesive failure happened in one sandblasted specimen. Conclusion: Intraoral sandblasting could significantly enhance the shear bond strength between enamel and composite resin.

18.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-537627

RESUMO

objective: To produce titanium dioxide hydrogel layer on the pure rough titanium(Ti) surface. Methods: Pure Ti discs( d =15mm) were polished to 600 grind, sandblasted and etched with acid, socked in 60 ℃ 5 mol/L NaOH solution for 24 h and then heated to 600℃ for an hour to get goughening, alkaline and heat treated Ti(RAH). The smooth, rough and RAH surfaces were analyzed with scanning electron microscope(SEM) and energy despersive X ray analysis(EDXA). Results: On smooth surfaces only regular polished grooves could be seen, while holes in different diameters formed on rough surfaces. A porous framework was found on the surfaces of the RAH observed by SEM. EDXA showed that the smooth and rough surfaces were consisted of 100% Ti, while there were a lot ofoxygen and sodium in RAH discs. Apatite formed on the RAH Ti surfaces when it is soaked in simulated body fluid for two weeks. Conclusion: A porous Ti dioxide hydrogel layer forms on the rough titanium substrate during alkaline and heat treatment.

19.
Artigo em Coreano | WPRIM (Pacífico Ocidental) | ID: wpr-649148

RESUMO

The purpose, of this study was to evaluate the effect of surface treatment of porcelain on tensile bond strength. To accomplish this purpose, this study was carried out with 120 samples which were divided into 12 groups with each 10 samples, and the first group was not surface treated, groups 2 through 5 underwent single surface treatment, and groups 6 through 12 underwent compound surface treatment. The results were as follows: 1. In statistic, all the single surface-treated groups showed higher tensile bond strength than the non surface-treated group and the sandblasted group showed the highest tensile bond strength as 10.34+/-2.50MPa. 2. All the compound surface-treated groups showed no noticeable difference in the tensile bond strength(9-11.5MPa). 3. In statistic, no significant difference was found between the sandblasted group and the compound surface-treated groups. 4. There was no fracture of porcelain while testing in this study. Above study demonstrated that compound surface treatment or sandblasing, if used single surface treatment, should be employed to guarantee successful clinical application.


Assuntos
Porcelana Dentária
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