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‣ Estudo comparativo de sistemas adesivos de fabricação nacional e importados: resistência de união à dentina, resistência à tração e micromorfologia; Comparative study of national and international adhesive systems: dentin bond strength, tensile strength and SEM

Soares, Fabio Zovico Maxnuck
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 27/09/2007 Português
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O objetivo deste trabalho foi comparar sistemas adesivos de fabricação nacional - Magic Bond DE (Vigodent), Master Bond (Biodinâmica) e Self Etch Bond (Vigodent) e similares importados - Adper Single Bond 2 (3M/ESPE) e Clearfil SE Bond (Kuraray) por meio da avaliação da resistência de união, resistência à tração e micromorfologia da interface. Para a avaliação da resistência de união foram utilizados vinte e cinco molares humanos hígidos (n=5). Os dentes foram preparados de modo a obterem-se superfícies planas em dentina, sobre as quais os sistemas adesivos foram aplicados seguindo as instruções dos fabricantes. Após 24 horas de armazenamento em água destilada a 37oC os dentes restaurados foram seccionados para obterem-se corpos-de-prova com área aderida de aproximadamente 0,8mm2. Metade dos corpos-de-prova foi submetida imediatamente ao teste de microtração, com velocidade de 0,5 mm/min até o momento da fratura. Os demais corpos de prova foram armazenados por mais 6 meses antes da realização do teste. A resistência à tração foi avaliada em corposde- prova (n=10) usinados em forma de haltere, com secção transversal aproximada de 0,4 mm2. O teste foi realizado em períodos idênticos aos do ensaio de microtração. Para a análise em microscopia eletrônica de varredura dois dentes foram preparados para cada sistema adesivo. Os valores obtidos foram submetidos à análise de variância e teste de correlação de Pearson. Os resultados obtidos no teste de resistência de união mostraram que...

‣ Effect of thermal treatments on tensile strength of commercially cast pure titanium and Ti-6Al-4V alloys

Rocha, Sicknan Soares da; Adabo, Gelson Luis; Vaz, Luis Geraldo; Henriques, Guilherme Elias Pessanha
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 759-766
Português
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Heating titanium structures is assumed to relieve tensions induced by the casting process as well as possibly optimizing some mechanical properties. The aim of this investigation was to evaluate the effect of thermal treatments on tensile strength of commercially pure titanium (CP Ti) and Ti-6Al-4V alloy. Thirty dumbbell rods, with diameters of 3.0 mm at the central segment and lengths of 42 mm, were cast for each metal using the Rematitan System. CP Ti and Ti-6Al-4V specimens were randomly divided into three groups of ten: a control group that received no thermal treatment and two test groups. One (T1) was heated at 750°C for 2 h and the other (T2) was annealed at 955°C for 1 h and aged at 620°C for 2 h. Tensile strength was measured with a universal testing machine (MTS model 810). Tensile strength means and standard deviations were statistically compared using a Kruskal-Wallis test at a α = 0.05 significance level. No statistically significant differences in tensile strength were observed among CP Ti groups. For the Ti-6Al-4V alloy, the control and T1 groups revealed statistically higher tensile strengths when compared to the T2 group, with no significant difference between the control and T1 groups. © 2005 Springer Science + Business Media...

‣ Influence of activation modes on diametral tensile strength of dual-curing resin cements.

Fonseca, Renata Garcia; Santos, Juliana Gomes dos; Adabo, Gelson Luis
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 267-271
Português
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In metallic restorations, the polymerization of dual-curing resin cements depends exclusively on chemical activation. The effect of the lack of photoactivation on the strength of these cements has been rarely studied. This study evaluated the influence of activation modes on the diametral tensile strength (DTS) of dual-curing resin cements. Base and catalyst pastes of Panavia F, Variolink II, Scotchbond Resin Cement, Rely X and Enforce were mixed and inserted into cylindrical metal moulds (4 x 2 mm). Cements were either: 1) not exposed to light (chemical activation = self-cured groups) or 2) photoactivated through mylar strips (chemical and photo-activation = dual-cured groups) (n = 10). After a 24 h storage in 37 masculineC distilled water, specimens were subjected to compressive load in a testing machine. A self-curing resin cement (Cement-It) and a zinc phosphate cement served as controls. Comparative analyses were performed: 1) between the activation modes for each dual-curing resin cement, using Students t test; 2) among the self-cured groups of the dual-curing resin cements and the control groups, using one-way ANOVA and Tukeys test (alpha = 0.05). The dual-cured groups of Scotchbond Resin Cement (53.3 MPa), Variolink II (48.4 MPa) and Rely X (51.6 MPa) showed higher DTS than that of self-cured groups (44.6...

‣ Diametral tensile strength of dual-curing resin cements submitted exclusively to autopolymerization.

Fonseca, Renata Garcia; Artusi, Thais Paci; Santos, Juliana Gomes dos; Adabo, Gelson Luis
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
693.4578%
OBJECTIVES: To evaluate, at different times, the diametral tensile strength (DTS) of dual-curing resin cements that were not photopolymerized. METHOD AND MATERIALS: Equal amounts of base and catalyst pastes of Panavia F (Kuraray), Variolink II (Vivadent), Rely X (3M ESPE), and Enforce (Dentsply) were mixed and inserted into cylindrical molds (4 x 2 mm) (n = 10). Cements were not photopolymerized. DTS test was performed in a testing machine at 30 minutes, 1 hour, 24 hours, and 7 days. The specimens were stored in light-proof containers with distilled water at 37 degrees C until the time of assay. An autopolymerizing resin cement (Cement-It, Jeneric Pentron) and a zinc phosphate cement served as controls. One-way analysis of variance (ANOVA) and Tukey test were performed separately for each cement and for each time (P <.05). RESULTS: All cements showed an increase in DTS when tested at 1 and 24 hours. Tests at 24 hours and 7 days revealed no statistically significant differences. In all groups, the zinc phosphate cement had the lowest DTS mean values (2.1 MPa, 3.6 MPa, 6.5 MPa, and 6.9 MPa), while Cement-It (35.1 MPa, 33.6 MPa, 46.9 MPa, and 46.3 MPa) and Enforce (31.9 MPa, 31.7 MPa, 43.4 MPa, and 47.6 MPa) presented the highest DTS mean values. CONCLUSION: All cements presented maximal strength at 24 hours. The dual-curing resin cements...

‣ Alloxan diabetes alters the tensile strength, morphological and morphometric parameters of abdominal wall healing in rats

Minossi, Jose Guilherme; Lima, Flavio De Oliveira; Caramori, Carlos Antonio; Hasimoto, Claudia Nishida; Ortolan, Erica Veruska Paiva; Rodrigues, Paulo Antonio; Spadella, Cesar Tadeu
Fonte: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia Publicador: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia
Tipo: Artigo de Revista Científica Formato: 118-124
Português
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PURPOSE:To investigate the effects of alloxan diabetes on the abdominal wall healing of rats undergoing laparotomy.METHODS:Ninety-six male Wistar rats weighing between 200 and 300 grams, divided into two groups: non-diabetic group (G1) and another with untreated diabetes (G2). Three months after diabetes induction, the animals underwent a 5cm-long- laparotomy and 5.0 nylon monofilament suture. After the surgery, 12 animals from each group were euthanized on days 4, 14, 21 and 30 corresponding to the moments M1, M2, M3 and M4. In each moment a fragment of the abdominal wall containing the scar was removed for tensile strength measurement, histological and morphometric study. Clinical and biochemical parameters were also analyzed.RESULTS:G2 animals showed parameters compatible with severe diabetes and decreased plasma levels of insulin. The tensile strength in G2 was significantly smaller in M2 and M4, with a tendency to fall in the other two. Through light microscope, diabetic animals showed more difficulty to increase collagen density and contraction. G2 animals showed high cellularity of fibroblasts in later healing moments, with collagen thinning in M2 and M4.CONCLUSION:The abdominal wound healing in untreated diabetic animals was altered and led to a higher incidence of dehiscence and infections.

‣ Development of a new test for determination of tensile strength of concrete blocks

Haach, Vladimir G.; Vasconcelos, Graça; Lourenço, Paulo B.
Fonte: Canada Masonry Symposium Publicador: Canada Masonry Symposium
Tipo: Conferência ou Objeto de Conferência
Publicado em //2013 Português
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An accurate experimental, numerical and analytical analysis of masonry structures is only possible if detailed information on the mechanical properties of masonry materials is known. In general, tensile strength of fragile brittle materials is a property difficult to measure in direct tensile tests. In this paper a new indirect tensile test method is proposed for determination of tensile strength of concrete blocks based on compression tests of blocks in the direction parallel to bed joints. Results of the proposed test are compared with direct tensile tests of small specimens cut from the concrete blocks. The compression test seems to be an alternative method of measuring the tensile strength of the units since it is easier to carry out and avoids problems like rotation of the specimen and debonding of the specimens from the plates.

‣ Assessement of tensile strength of graphites by the Iosipescu coupon test

Manhani,Luis Guilherme Borzani; Pardini,Luiz Claudio; Levy Neto,Flamínio
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2007 Português
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Polycrystalline graphites are widely used in the metallurgical, nuclear and aerospace industries. Graphites are particulated composites manufactured with a mixture of coke with pitch, and changes in relative proportions of these materials cause modifications in their mechanical properties. Uniaxial tension tests must be avoided for mechanical characterization in this kind of brittle material, due to difficulties in making the relatively long specimens and premature damages caused during testing set-up. On other types of tests, e.g. bending tests, the specimens are submitted to combined stress states (normal and transverse shear stresses). The Iosipescu shear test, is performed in a beam with two 90° opposite notches machined at the mid-length of the specimens, by applying two forces couples, so that a pure and uniform shear stress state is generated at the cross section between the two notches. When a material is isotropic and brittle, a failure at 45° in relation to the beam long axis can take place, i.e., the tensile normal stress acts parallel to the lateral surface of the notches, controls the failure and the result of the shear test is numerically equivalent to the tensile strength. This work has evaluated a graphite of the type used in rocket nozzles by the Iosipescu test and the resulted stress...

‣ Diameter dependence of tensile strength by Weibull analysis: Part I bamboo fiber

Costa,L.L. da; Loiola,R.L.; Monteiro,S.N.
Fonte: Rede Latino-Americana de Materiais Publicador: Rede Latino-Americana de Materiais
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 Português
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Fibers stripped of from the bamboo culm by longitudinal cutting are being considered as reinforcement of polymer composites owing to environmental benefits related to their biodegradable and renewable characteristics. The manual cutting process allows bamboo fibers with different diameters to be extracted from the culm. Since a lignocellulosic fiber usually presents tensile strength dependence with its diameter, this possibility was investigated on bamboo fibers by means of the Weibull statistical analysis. It was found that the smaller the fiber diameter, the greater the tensile strength. Fracture observation of ruptured bamboo fibers by scanning electron microscopy, identified possible mechanisms associated with this inverse strength/diameter correlation.

‣ Diametral tensile strength and water sorption of glass-ionomer cements used in Atraumatic Restorative Treatment

Cefaly,Daniela Francisca Gigo; Franco,Eduardo Batista; Mondelli,Rafael Francisco Lia; Francisconi,Paulo Afonso Silveira; Navarro,Maria Fidela de Lima
Fonte: Faculdade De Odontologia De Bauru - USP Publicador: Faculdade De Odontologia De Bauru - USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2003 Português
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697.3992%
The purposes of this study were to evaluate the diametral tensile strength and the water sorption of restorative (Fuji IX and Ketac Molar) and resin-modified glass-ionomer luting cements (ProTec Cem, Fuji Plus and Vitremer) mixed at both manufacturer and increased powder: liquid ratio, for their use in the Atraumatic Restorative Treatment. A conventional restorative glass-ionomer (Ketac Fil) was used as control. Specimens (6.0 mm in diameter x 3.0 mm in height) were prepared and stored (1 hour, 1 day and 1 week) for a diametral tensile strength test. Data were subjected to two-way ANOVA and Tukey tests (p<0.05). For the water sorption test, specimens of 15.0 mm in diameter x 0.5 mm in height were prepared and transfered to desiccators until a constant mass was obtained. Then the specimens were immersed in deionized water for 7 days, weighed and reconditioned to a constant mass in desiccators. Data were subjected to one-way ANOVA and Tukey tests (p<0.05). Five specimens of each studied material and consistency were prepared for each test. The resin-modified glass-ionomer cements showed significantly higher strength than the conventional materials. Except for ProTec Cem, the diametral tensile strength of the resin-modified materials significantly increased from luting to restorative consistency. Except for ProTec Cem...

‣ Influence of the final temperature of investment healting on the tensile strength and Vickers hardness of CP Ti and Ti-6Al-4V alloy

Oliveira,Pedro César Garcia; Adabo,Gelson Luis; Ribeiro,Ricardo Faria; Rocha,Sicknan Soares da; Ávila,Fabiano Araújo; Valle,Accácio Lins do
Fonte: Faculdade De Odontologia De Bauru - USP Publicador: Faculdade De Odontologia De Bauru - USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2007 Português
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The aim of the work was to evaluate the influence of the temperature of investment healting on the tensile strength and Vickers hardness of CP Ti and Ti-6Al-4V alloy casting. Were obtained for the tensile strength test dumbbell rods that were invested in the Rematitan Plus investment and casting in the Discovery machine cast. Thirty specimens were obtained, fiftten to the CP Titanium and fifteen to the Ti-6Al-4V alloy, five samples to each an of the three temperatures of investment: 430ºC (control group), 480ºC and 530ºC. The tensile test was measured by means of a universal testing machine, MTS model 810, at a strain of 1.0 mm/min. After the tensile strenght test the specimens were secctioned, embedded and polished to hardness measurements, using a Vickers tester, Micromet 2100. The means values to tensile tests to the temperatures 430ºC, 480 and 530: CP Ti (486.1 - 501.16 - 498.14 -mean 495.30 MPa) and Ti-6Al-4V alloy (961.33 - 958.26 - 1005.80 - mean 975.13 MPa) while for the Vickers hardness the values were (198.06, 197.85, 202.58 - mean 199.50) and (352.95, 339.36, 344.76 - mean 345.69), respectively. The values were submitted to Analysis of Variance (ANOVA) and Tukey,s Test that indicate differences significant only between the materials...

‣ The effect of different light-curing units on tensile strength and microhardness of a composite resin

Franco,Eduardo Batista; Santos,Patrícia Aleixo dos; Mondelli,Rafael Francisco Lia
Fonte: Faculdade De Odontologia De Bauru - USP Publicador: Faculdade De Odontologia De Bauru - USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2007 Português
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The aim of this study was to evaluate the influence of different light-curing units on the tensile bond strength and microhardness of a composite resin (Filtek Z250 - 3M/ESPE). Conventional halogen (Curing Light 2500 - 3M/ESPE; CL) and two blue light emitting diode curing units (Ultraled - Dabi/Atlante; UL; Ultrablue IS - DMC; UB3 and UB6) were selected for this study. Different light intensities (670, 130, 300, and 600 mW/cm², respectively) and different curing times (20s, 40s and 60s) were evaluated. Knoop microhardness test was performed in the area corresponding to the fractured region of the specimen. A total of 12 groups (n=10) were established and the specimens were prepared using a stainless steel mold composed by two similar parts that contained a cone-shaped hole with two diameters (8.0 mm and 5.0 mm) and thickness of 1.0 mm. Next, the specimens were loaded in tensile strength until fracture in a universal testing machine at a crosshead speed of 0.5 mm/min and a 50 kg load cell. For the microhardness test, the same matrix was used to fabricate the specimens (12 groups; n=5). Microhardness was determined on the surfaces that were not exposed to the light source, using a Shimadzu HMV-2 Microhardness Tester at a static load of 50 g for 30 seconds. Data were analyzed statistically by two-way ANOVA and Tukey's test (p<0.05). Regarding the individual performance of the light-curing units...

‣ Considerations that may influence the result of trials assessing tensile strength in experimental surgery

Rossi,Lucas Félix; Ramos,Renata Ribeiro; Ely,Jorge Bins; Kestering,Darlan de Medeiros; Soldi,Marly da Silveira; Brum,Sandro Polidoro Berni; d`Acampora,Armando José
Fonte: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia Publicador: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2007 Português
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PURPOSE: To provide information gathered upon the execution of trials assessing tensile strength in experimental surgeries. METHODS: Descriptive study considering details on the execution of trials assessing tensile strength in experimental surgery. RESULTS: The analysis of the rupture force in a mechanical test machine is an adequate technique since it provides precise and quick results. It can, undoubtedly, be developed in this context of the eminently mechanical analysis of trials on experimental surgery. CONCLUSION: The utilization of a mechanical test machine is a useful tool in the assessment of materials' strength, providing accurate results. Nevertheless the trials must be well structured analyzing the multiple variables so as to attain a pattern of constant reproducibility and to provide the necessary reliability.

‣ In Vitro Tensile Strength of Luting Cements on Metallic Substrate

Orsi,Iara A.; Varoli,Fernando K.; Pieroni,Carlos H.P.; Ferreira,Marly C.C.G.; Borie,Eduardo
Fonte: Fundação Odontológica de Ribeirão Preto Publicador: Fundação Odontológica de Ribeirão Preto
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2014 Português
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The aim of this study was to determine the tensile strength of crowns cemented on metallic substrate with four different types of luting agents. Twenty human maxillary molars with similar diameters were selected and prepared to receive metallic core castings (Cu-Al). After cementation and preparation the cores were measured and the area of crown's portion was calculated. The teeth were divided into four groups based on the luting agent used to cement the crowns: zinc phosphate cement; glass ionomer cement; resin cement Rely X; and resin cement Panavia F. The teeth with the crowns cemented were subjected to thermocycling and later to the tensile strength test using universal testing machine with a load cell of 200 kgf and a crosshead speed of 0.5 mm/min. The load required to dislodge the crowns was recorded and converted to MPa/mm2. Data were subjected to Kruskal-Wallis analysis with a significance level of 1%. Panavia F showed significantly higher retention in core casts (3.067 MPa/mm2), when compared with the other cements. Rely X showed a mean retention value of 1.877 MPa/mm2 and the zinc phosphate cement with 1.155 MPa/mm2. Glass ionomer cement (0.884 MPa/mm2) exhibited the lowest tensile strength value. Crowns cemented with Panavia F on cast metallic posts and cores presented higher tensile strength. The glass ionomer cement showed the lowest tensile strength among all the cements studied.

‣ Compressive and diametral tensile strength of glass ionomer cements

Bresciani,Eduardo; Barata,Terezinha de Jesus Esteves; Fagundes,Ticiane Cestari; Adachi,Akimi; Terrin,Marina Martins; Navarro,Maria Fidela de Lima
Fonte: Faculdade De Odontologia De Bauru - USP Publicador: Faculdade De Odontologia De Bauru - USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2004 Português
Relevância na Pesquisa
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The aim of this study was to compare, in different periods of time, the compressive and diametral tensile strength of a traditional high viscous glass ionomer cement: Fuji IX (GC Corporation), with two new Brazilian GIC's: Vitro-Molar (DFL) and Bioglass R (Biodinamica), all indicated for the Atraumatic Restorative Treatment (ART) technique. Fifteen disk specimens (6.0mm diameter x 3.0mm height) for the diametral tensile strength (DTS) test and fifteen cylindrical specimens (6.0mm diameter x 12.0mm height) for the compressive strength (CS) test were made of each GIC. Specimens were stored in deionized water at 37º C and 100% of humidity in a stove until testing. Five specimens of each GIC were submitted to CS and DTS test in each period, namely 1 hour, 24 hours and 7 days. The specimens were tested in a testing machine (Emic) at a crosshead speed of 1.0mm/min for CS and 0.5mm/min for the DTS test until failure occurred. The data were submitted to two-way ANOVA and Tukey tests (alpha=0.05). The mean CS values ranged from 42.03 to 155.47MPa and means DTS from 5.54 to 13.72 MPa, with test periods from 1h to 7 days. The CS and DTS tests showed no statistically significant difference between Fuji IX and Vitro Molar, except for CS test at 1-hour period. Bioglass R had lowest mean value for CS of the cements tested. In DTS test Bioglass R presented no statistically significant differences when compared with all others tested GICs at 1-hour period and Bioglass R presented no difference at 24-hour and 7-day periods when compared to Vitro-Molar. Further studies to investigate other physical properties such as fracture toughness and wear resistance...

‣ Influence of core-finishing intervals on tensile strength of cast posts-and-cores luted with zinc phosphate cement

Iglesias,Michele Andrea Lopes; Mesquita,Gabriela Campos; Pereira,Analice Giovani; Dantas,Lucas Costa de Medeiros; Raposo,Luís Henrique Araújo; Soares,Carlos José; Mota,Adérito Soares da
Fonte: Sociedade Brasileira de Pesquisa Odontológica - SBPqO Publicador: Sociedade Brasileira de Pesquisa Odontológica - SBPqO
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2012 Português
Relevância na Pesquisa
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The core finishing of cast posts-and-cores after luting is routine in dental practice. However, the effects of the vibrations produced by the rotary cutting instruments over the luting cements are not well-documented. This study evaluated the influence of the time intervals that elapsed between the cementation and the core-finishing procedures on the tensile strength of cast posts-and-cores luted with zinc phosphate cement. Forty-eight bovine incisor roots were selected, endodontically treated, and divided into four groups (n = 12): GA, control (without finishing); GB, GC, and GD, subjected to finishing at 20 minutes, 60 minutes, and 24 hours after cementation, respectively. Root canals were molded, and the resin patterns were cast in copper-aluminum alloy. Cast posts-and-cores were luted with zinc phosphate cement, and the core-finishing procedures were applied according to the groups. The tensile tests were performed at a crosshead speed of 0.5 mm/min for all groups, 24 hours after the core-finishing procedures. The data were subjected to one-way analysis of variance (ANOVA) and Tukey's test (α = 0.05). No significant differences were observed in the tensile strengths between the control and experimental groups, regardless of the time interval that elapsed between the luting and finishing steps. Within the limitations of the present study...

‣ Tensile strength study of the abdominal wall following laparotomy synthesis using three types of surgical wires in Wistar rats

Rossi,Lucas Félix; Ramos,Renata Ribeiro; Kestering,Darlan de Medeiros; Soldi,Marly da Silveira; Ely,Jorge Bins; d'Acampora,Armando José
Fonte: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia Publicador: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2008 Português
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PURPOSE: To study the tensile strength of the abdominal wall following laparotomy synthesis utilizing three types of surgical wires. METHODS: Thirty Wistar rats were randomized into three groups of ten rats each. Each group underwent a 3cm-laparotomy which was closed with 3-0 polyglactin 910, polyglecrapone and catgut wires. After 63 days, euthanasia was performed and part of the abdominal wall was removed with which a strip was produced measuring 2.0 cm in length by 6.0 cm in width comprising the abdominal muscles with the implanted mesh. The sample was fixed in a mechanical test machine in which constant force was applied contrary to the tissue strips. Maximum force was considered, expressed in Newton, until full rupture of the tissue occurred. The non-parametrical Kruskal - Wallis test was used for the statistical analysis, admitting p<0.05. RESULTS: The average strength of the catgut group was slightly lower (33.50 N) than that of the polyglactin group (34.23 N), the difference not being statistically significant (p=0.733). The polyglecaprone group was the one which presented the lowest strength value of all three wires analyzed (29.86 N). No statistical difference was obtained when comparing the strength values of the polyglecaprone group and the catgut group (p=0.06 ). However...

‣ Resistência à compressão e à tração diametral de cimentos de ionômero de vidro; Compressive and diametral tensile strength of glass ionomer cements

Bresciani, Eduardo; Barata, Terezinha de Jesus Esteves; Fagundes, Ticiane Cestari; Adachi, Akimi; Terrin, Marina Martins; Navarro, Maria Fidela de Lima
Fonte: Universidade de São Paulo. Faculdade de Odontologia de Bauru Publicador: Universidade de São Paulo. Faculdade de Odontologia de Bauru
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; Formato: application/pdf
Publicado em 01/12/2004 Português
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Comparou-se a Resistência à Compressão (RC) e à Tração Diametral (TD) de um cimento de ionômero de vidro de alta viscosidade [Fuji IX (GC Corporation)] e de dois novos cimentos Brasileiros [Vitro Molar (DFL) e Bioglass R (Biodinamica)], recentemente lançados no mercado, ambos indicados para o Tratamento Restaurador Atraumático (ART), em diferentes períodos de tempo. Foram confeccionados quinze corpos-de-prova com 6,0 mm de diâmetro x 3,0 mm de altura para o teste de TD e quinze com 6,0 mm de diâmetro e 12,0 mm de altura para o teste de RC, para cada ionômero a ser testado. Os corpos-de-prova foram armazenados em recipientes plásticos, com água deionizada, e mantidos em estufa a 37ºC e 100% de umidade, até a realização dos testes. Cinco corpos-de-prova de cada material foram submetidos aos testes de TD e RC em cada período de tempo: 1-hora, 24-horas e 7-dias, em uma máquina de testes universal (EMIC - DL 500) a uma velocidade de 1,0 mm/min para RC e 0,5mm/min para TD. Os dados obtidos foram submetidos aos testes ANOVA a dois critérios e Tukey (á=0,05). Os valores médios de RC e TD variaram de 42,03 a 155.47 MPa e de 5,54 a 13,72 MPa, respectivamente para os períodos analisados. O Fuji IX e o Vitro Molar não apresentaram diferenças em relação aos testes de RC e TD...

‣ Influence of the final temperature of investment healting on the tensile strength and Vickers hardness of CP Ti and Ti-6Al-4V alloy

Oliveira, Pedro César Garcia; Adabo, Gelson Luis; Ribeiro, Ricardo Faria; Rocha, Sicknan Soares da; Ávila, Fabiano Araújo; Valle, Accácio Lins do
Fonte: Universidade de São Paulo. Faculdade de Odontologia de Bauru Publicador: Universidade de São Paulo. Faculdade de Odontologia de Bauru
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; Formato: application/pdf
Publicado em 01/02/2007 Português
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The aim of the work was to evaluate the influence of the temperature of investment healting on the tensile strength and Vickers hardness of CP Ti and Ti-6Al-4V alloy casting. Were obtained for the tensile strength test dumbbell rods that were invested in the Rematitan Plus investment and casting in the Discovery machine cast. Thirty specimens were obtained, fiftten to the CP Titanium and fifteen to the Ti-6Al-4V alloy, five samples to each an of the three temperatures of investment: 430ºC (control group), 480ºC and 530ºC. The tensile test was measured by means of a universal testing machine, MTS model 810, at a strain of 1.0 mm/min. After the tensile strenght test the specimens were secctioned, embedded and polished to hardness measurements, using a Vickers tester, Micromet 2100. The means values to tensile tests to the temperatures 430ºC, 480 and 530: CP Ti (486.1 - 501.16 - 498.14 -mean 495.30 MPa) and Ti-6Al-4V alloy (961.33 - 958.26 - 1005.80 - mean 975.13 MPa) while for the Vickers hardness the values were (198.06, 197.85, 202.58 - mean 199.50) and (352.95, 339.36, 344.76 - mean 345.69), respectively. The values were submitted to Analysis of Variance (ANOVA) and Tukey,s Test that indicate differences significant only between the materials...

‣ Tensile strength testing of thin spray-on liner products (TSLs) and shotcrete

Yilmaz,H.
Fonte: Journal of the Southern African Institute of Mining and Metallurgy Publicador: Journal of the Southern African Institute of Mining and Metallurgy
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2010 Português
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Tensile strength testing has been one of the most common physical property testing methods of thin spray-on liner (TSL) products worldwide. However, the variety of products tested has been insufficient for comparison purposes. Specimen preparation procedures and test parameters such as curing time and loading rate are not reported well. Comprehensive tensile strength testing on 20 TSL products and one plain shotcrete brand was performed over 28 days of curing period. Detailed information on the test procedures with particular attention on the important aspects during sample preparation and test execution are provided. As expected, the tensile strength increases with increasing curing period. The test results make the categorization and comparison of liner products possible.

‣ Effect of post length on endodontically treated teeth: analyses of tensile strength

Pereira, Jefferson Ricardo; Valle, Accácio Lins do; Shiratori, Fábio Kenji; Ghizoni, Janaina Salomon
Fonte: UNICAMP/FOP Publicador: UNICAMP/FOP
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; Formato: application/pdf
Publicado em 05/11/2015 Português
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Aim: This study compared the tensile strength of endodontically treated teeth restored with different posts and cores with different post lengths. Methods: Sixty extracted intact canines were randomly divided into 6 groups. Groups CP1, CP2 and CP3 were restored with custom cast postand-core and groups PF1, PF2 and PF3 were restored with prefabricated post and composite resin core, with different combinations of post length of 5,0 mm, 7.5 mm and 10 mm, respectively (n = 10). All teeth were restored with a total metal crown. A tensile loading was applied at a 180- degree angle to the long axis until failure. Results: The 2-way analysis of variance (á=0.05) showed statistically significant difference (p<0.001) among the groups. However, when the mean fracture forces for the groups were compared (Groups 1, 2, 3, 4, 5 and 6: 134.5 N (34.2), 178.9N (40.1), 271,5 N (55.9), 161.7 N (22.0), 216.1 N (42.0) and 257.9 N (41.0), respectively), no significant differences could be detected among the groups restored with prefabricated post and cast post-and-core. It was found significant differences when it was compared the different lengths for each type of post (p<.05). Conclusions: This study showed that increasing post length significantly increased the tensile strength of prefabricated posts and cast post-and-core used in endodontically treated teeth. On the other hand...