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Avaliação in vitro da ação do hipoclorito de sódio e de pastilhas efervescentes quanto à alteração de cor em resinas acrílicas termopolimerizáveis e de microondas; In vitro evaluation of sodium hypochlorite and effervescent tablets actionregarding color alteration of heat and microwave-polymerized acrylic resins

Peracini, Amanda
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 10/07/2008 PT
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68.99242%
O objetivo deste estudo foi avaliar a alteração de cor de resinas acrílicas termopolimerizáveis (convencional e de microondas) após imersões em soluções químicas higienizadoras de próteses totais em diferentes períodos de tempo. Foram obtidos padrões em cera (15mm de diâmetro e 4mm de espessura), a partir de uma matriz de teflon, que foram incluídos em muflas convencionais e para microondas. Após a eliminação da cera, as resinas foram manipuladas, prensadas e polimerizadas segundo as instruções dos fabricantes. Foram confeccionados 200 corpos-de-prova, 100 de cada marca comercial das resinas Lucitone 550 (L) e Onda Cryl (OC), os quais foram imersos nas soluções: A)Água destilada-3 min.; B)Bony Plus -3 min.; C)Água destilada-5 min.; D)Corega Tabs-5 min.; E)Água destilada-20 min.; F)Hipoclorito de sódio a 0,5%-20 min.; G)Hipoclorito de sódio a 1%-20 min.; H)Água destilada-8 horas; I)Hipoclorito de sódio a 0,5%-8 horas; J)Hipoclorito de sódio a 1%-8 horas. A alteração de cor foi avaliada empregando-se um espectrocolorímetro (Color Guide 45/0 BYK-Gardner) antes e após a simulação de 180 dias de imersão. Os resultados foram comparados por meio da análise de variância (ANOVA) para dois fatores, seguida pelo teste de Student-Newman Keuls...

Incorporação de ácido metacrílico em resinas acrílicas para base de prótese; Incorporation of methacrylic acid in denture base acrylic resins

Azevedo, Alessandra Miranda de
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 30/06/2009 PT
Relevância na Pesquisa
68.854473%
A resina acrílica para base de próteses removíveis é capaz de aderir Candida spp. sobre sua superfície, possibilitando o aparecimento das estomatites protéticas. Um fator importante para essa aderência é a hidrofobicidade do polímero. Assim, a adição de radicais hidrofílicos à resina acrílica tem potencial de torná-la menos suscetível à formação de biofilmes, e merece ser investigado. O objetivo deste projeto foi avaliar os efeitos da copolimerização do ácido metacrílico sobre aderência microbiana e propriedades físicas em um material à base de polimetil metacrilato para base de próteses removíveis. Para os ensaios com a resina acrílica, espécimes de diferentes formatos foram divididos em grupos, conforme a concentração do ácido metacrílico, em volume, na porção líquida da resina (A: 0%; B: 10%; C: 20%, D:50%). A aderência de Candida albicans foi avaliada por meio da contagem de unidades formadoras de colônia (UFC) aderidas sobre os espécimes mantidos em caldo de cultura. Também foi estudadas a dureza Vickers, a resistência flexural, a rugosidade e a estabilidade de cor. Os grupos foram descritos por média ± desvios padrão e comparados, dentro de cada variável, por meio de ANOVA, com α = 0...

Development and application of methods for determination of residual monomer in dental acrylic resins using high performance liquid chromatography

Urban, V. M.; Cass, Q. B.; Oliveira, R. V.; Giampaolo, E. T.; Machado, A. L.
Fonte: Wiley-Blackwell Publicador: Wiley-Blackwell
Tipo: Artigo de Revista Científica Formato: 369-376
ENG
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Two high-performance liquid chromatographic methods for determination of residual monomer in dental acrylic resins are described. Monomers were detected by their UV absorbance at 230 nm, on a Nucleosil((R)) C-18 (5 mu m particle size, 100 angstrom pore size, 15 x 0.46 cm i.d.) column. The separation was performed using acetonitrile-water (55:45 v/v) containing 0.01% triethylamine (TEA) for methyl methacrylate and butyl methacrylate, and acetonitrile-water (60:40 v/v) containing 0.01% TEA for isobutyl methacrylate and 1,6-hexanediol dimethacrylate as mobile phases, at a flow rate of 0.8 mL/min. Good linear relationships were obtained in the concentration range 5.0-80.0 mu g/mL for methyl methacrylate, 10.0-160.0 mu g/mL for butyl methacrylate, 50.0-500.0 mu g/mL for isobutyl methacrylate and 2.5-180.0 mu g/mL for 1,6-hexanediol dimethacrylate. Adequate assay for intra- and inter-day precision and accuracy was observed during the validation process. An extraction procedure to remove residual monomer from the acrylic resins was also established. Residual monomer was obtained from broken specimens of acrylic disks using methanol as extraction solvent for 2 h in an ice-bath. The developed methods and the extraction procedure were applied to dental acrylic resins...

Effect of thermal cycling on microleakage between hard chairside relines and denture base acrylic resins

Giampaolo, Eunice Teresinha; Jorge, Janaina Habib; Machado, Ana Lucia; Pavarina, Ana Claudia; Vergani, Carlos Eduardo
Fonte: Wiley-Blackwell Publicador: Wiley-Blackwell
Tipo: Artigo de Revista Científica Formato: 121-126
ENG
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Objectives:Microleakage is a pre-stage of debonding between hard chairside relines and denture base acrylic resins. Therefore, it is important to assess them with regard to the longevity of the relined denture. This study investigated the effect of thermal cycling on the microleakage at the interface of three hard chairside reline resins and three denture base resins.Material and methods:Rectangular bars (12 mm x 3 mm x 3 mm) of Lucitone 550, Acron MC and QC 20 were made and relined with Kooliner, Tokuyama Rebase Fast II and Ufi Gel Hard, Lucitone 550, Acron MC and QC 20 resins. Specimens were divided into one control and two test groups (n = 10). In specimens of the control group, the microleakage was performed after the reline procedure. In Test Group 1, the specimens were stored for 24 h in distilled water at room temperature and in Test Group 2; the specimens were thermal cycled from 5 to 55 degrees C for 5000 cycles with a 30-s dwell time. Subsequently, all specimens were immersed in 50% silver nitrate solutions for 24 h. All specimens were sectioned longitudinally into three fractions and the lateral sections were examined (n = 20). Silver nitrate stain penetration was examined under a stereoscopic lens with x30 magnification...

Water sorption, solubility, and bond strength of two autopolymerizing acrylic resins and one heat-polymerizing acrylic resin.

Cucci, A. L.; Vergani, Carlos Eduardo; Giampaolo, E. T.; Afonso, M. C.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 434-438
ENG
Relevância na Pesquisa
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STATEMENT OF PROBLEM: Because water sorption of autopolymerizing acrylic reline resins is accompanied by volumetric change, it is a physical property of importance. As residual monomer leaches into the oral fluids and causes tissue irritation, low solubility of these resins is desired. Another requirement is a satisfactory bond between the autopolymerizing acrylic resins and the denture base acrylic resin. PURPOSE: This study compared the water sorption, solubility, and the transverse bond strength of 2 autopolymerizing acrylic resins (Duraliner II and Kooliner) and 1 heat-polymerizing acrylic resin (Lucitone 550). MATERIAL AND METHODS: The water sorption and solubility test was performed as per International Standards Organization Specification No. 1567 for denture base polymers. Bond strengths between the autopolymerizing acrylic resins and the heat-polymerizing acrylic resin were determine with a 3-point loading test made on specimens immersed in distilled water at 37 degrees C for 50 hours and for 30 days. Visual inspection determined whether failures were adhesive or cohesive. RESULTS: Duraliner II acrylic resin showed significantly lower water sorption than Kooliner and Lucitone 550 acrylic resins. No difference was noted in the solubility of all materials. Kooliner acrylic resin demonstrated significantly lower transverse bond strength to denture base acrylic resin and failed adhesively. The failures seen with Duraliner II acrylic resin were primarily cohesive in nature. CONCLUSIONS: Autopolymerizing acrylic reline resins met water sorption and solubility requirements. However...

Assessment of the flexural strength of two heat-curing acrylic resins for artificial eyes

Fernandes, Aline Úrsula Rocha; Portugal, Aline; Veloso, Letícia Rocha; Goiato, Marcelo Coelho; dos Santos, Daniela Micheline
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 263-267
ENG
Relevância na Pesquisa
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Prosthetic eyes are artificial substitutes for the eyeball, made of heat-curing acrylic resin, serving to improve the esthetic appearance of the mutilated patient and his/her inclusion in society. The aim of this study was to assess the flexural strength of two heat-curing acrylic resins used for manufacturing prosthetic eyes. Thirty-six specimens measuring 64 x 10 x 3.3 mm were obtained and divided into four groups: acrylic resin for artificial sclera N1 (Artigos Odontológicos Clássico, São Paulo, SP, Brazil), heat-cure water technique (GI) and microwave-cured (GII); colorless acrylic resin for prosthetic eyes (Artigos Odontológicos Clássico, São Paulo, SP, Brazil), heat-cure water technique (GIII) and microwave-cured (GIV). Mechanical tests using three point loads were performed in a test machine (EMIC, São José dos Pinhais, PR, Brazil). The analysis of variance and the Tukey test were used to identify significant differences (p < 0.01). Groups GII and GIV presented, respectively, the highest (98.70 ± 11.90 MPa) and lowest means (71.07 ± 8.93 MPa), with a statistically significant difference. The cure method used for the prosthetic eye resins did not interfere in their flexural strength. It was concluded that all the resins assessed presented sufficient flexural strength values to be recommended for the manufacture of prosthetic eyes.

Effect of different disinfectants on the microhardness and roughness of acrylic resins for ocular prosthesis

Moreno, Amália; Goiato, Marcelo C.; Dos Santos, Daniela M.; Haddad, Marcela F.; Pesqueira, Aldiéris A.; Bannwart, Lisiane C.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 32-39
ENG
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Background: Ocular prosthesis materials should have specific properties for their indication and durability; therefore, it is important to investigate their physical behaviour when affected by several disinfectants. Objectives: This study evaluated the influence of different disinfecting solutions on the microhardness and surface roughness of acrylic resins for ocular prosthesis. Materials and Methods: Fifty samples simulating ocular prostheses were fabricated with N1 resin and colourless resin and divided (n = 10) according to the disinfectant used: neutral soap, Opti-free, Efferdent, 1% hypochlorite (HYC) and 4% chlorhexidine (CHX). Samples were stored in saline solution at 37°C and disinfected during 120 days. Both microhardness and roughness were investigated before, after 60 days and 120 days of disinfection and storage. Microhardness was measured using a microhardner and the roughness with a roughness device. Results: N1 resin showed lower microhardness when compared with colourless resin (p < 0.05). HYC and CHX groups exhibited the highest change of microhardness and roughness values (p < 0.05). An increase in roughness and reduction in microhardness of ocular acrylic resins were observed after both periods of disinfection and storage (p < 0.05). Conclusion: Both disinfection/storage periods affected the microhardness and roughness values of the samples. © 2012 The Gerodontology Society and John Wiley & Sons A/S.

Influence of plaster drying on the amount of residual monomer in heat-cured acrylic resins

De Arruda Paes-Junior, Tarcisio José; De Carvalho, Rodrigo Furtado; Cavalcanti, Sâmia Carolina Mota; Saavedra, Guilherme de Siqueira Ferreira Anzaloni; Borges, Alexandre Luiz Souto
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 84-89
ENG
Relevância na Pesquisa
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Aim: To evaluate the influence of plaster condition, dry or not, on the amount of residual monomer in heat-cured acrylic resin. Methods: Thirty acrylic resin specimens (65×10×3 mm) were fabricated and randomly assigned to 5 groups (n=6). The evaluated resins were heat-cured acrylic resins by conventional or microwave polymerization techniques and the plaster was previously dried in microwave oven in two groups. Each specimen was individually immersed in a test tube containing methanol (7 days) for surface analysis. In the groups for which internal monomer was evaluated, the specimens were fragmented and the small fragments were weighed prior to immersion in methanol. The analysis was made by high performance liquid chromatography (HPLC). Data were analyzed by ANOVA and Tukey test (p<5%) Results: showed statistical differences among the groups. Conclusions: The previous plaster drying influenced the residual monomer amount showing a decrease of these levels.

Aderencia de Candida spp. a resinas acrilicas : metodo de polimerização e presença ou não de saliva; Adherence assay of Candida spp. on acrylic resins: polymerization methods and presence of saliva

Juliana Silva Moura
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 22/11/2005 PT
Relevância na Pesquisa
68.92486%
O objetivo deste trabalho foi avaliar a influência do método de polimerização e a presença da saliva humana na aderência de Candida spp. às superfícies de resinas acrílicas. Duzentas e cinqüenta e seis amostras retangulares (2,5 x 1,2 x 0,2 cm), confeccionadas com resinas polimerizadas por banho de água ou microondas foram avaliadas para rugosidade e energia livre de superfície e em seguida utilizadas para o ensaio de aderência de Candida spp. Para este propósito, as amostras foram aleatoriamente divididas em 8 grupos por resina, sendo quatro expostos durante 30 min a saliva humana. Em seguida, as amostras foram posicionadas verticalmente em tubos de plásticos estéreis contendo meio de cultura Sabouraud e uma entre quatro suspensões de Candida: Candida albicans, Candida tropicalis, Candida dubliniensis e Cândida glabrata (1 a 5 x 106 células / mL). A contagem das células aderidas foi realizada em microscópio óptico com 400 x de aumento. Os dados de rugosidade superficial e energia de superfície foram submetidos a ANOVA um fator e teste t. Não houve diferença estatística significante para rugosidade (p > 0,05), enquanto maiores valores de energia livre de superfície foram encontrados para a resina polimerizada por banho de água (p < 0...

Propriedades mecanicas de resinas acrilicas para base de protese antes e apos metodos de reparos; Mechanical properties of denture base acrylic resins before and after repair methods

Fernanda Faot
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 10/11/2006 PT
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69.422046%
Fraturas por impacto e flexão ainda são os principais problemas relatados tanto pelos portadores de próteses removíveis como pelos cirurgiões dentistas. Na tentativa de solucionar esse problema, alterações na composição química das resinas acrílicas como a inclusão de co-polímeros, adição de agente de ligação cruzada e a incorporação de partículas de borracha na forma de butadieno estireno têm sido propostas. Entretanto, poucos estudos avaliaram a incorporação destes aditivos modificadores de impacto no processo de fratura, deformação e microestrutura de resinas acrílicas. Além disso, devido à fragilidade dos materiais poliméricos a presença de trincas e fraturas em base de próteses removíveis ainda é alta e reparos são procedimentos comuns tanto por métodos diretos ou indiretos. Entretanto, as propriedades mecânicas de resinas acrílicas reparadas ainda não estão claramente descritas. Assim, os objetivos do presente trabalho foram: I) avaliar a resistência ao impacto e a flexão, bem como tensão de ruptura, módulo Young e deslocamento de escoamento de resinas acrílicas contendo modificadores de impacto e analisar sua microestrutura; II) determinar a resistência ao impacto e flexão de resinas acrílicas para base de prótese previamente fraturadas e reparadas com resinas fotopolimerizável...

Influence of plaster drying on the amount of residual monomer in heat-cured acrylic resins

Paes-Junior,Tarcisio José de Arruda; Carvalho,Rodrigo Furtado de; Cavalcanti,Sâmia Carolina Mota; Saavedra,Guilherme de Siqueira Ferreira Anzaloni; Borges,Alexandre Luiz Souto
Fonte: Faculdade de Odontologia de Piracicaba - UNICAMP Publicador: Faculdade de Odontologia de Piracicaba - UNICAMP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2013 EN
Relevância na Pesquisa
68.92486%
AIM: To evaluate the influence of plaster condition, dry or not, on the amount of residual monomer in heat-cured acrylic resin. METHODS: Thirty acrylic resin specimens (65x10x3 mm) were fabricated and randomly assigned to 5 groups (n=6). The evaluated resins were heat-cured acrylic resins by conventional or microwave polymerization techniques and the plaster was previously dried in microwave oven in two groups. Each specimen was individually immersed in a test tube containing methanol (7 days) for surface analysis. In the groups for which internal monomer was evaluated, the specimens were fragmented and the small fragments were weighed prior to immersion in methanol. The analysis was made by high performance liquid chromatography (HPLC). Data were analyzed by ANOVA and Tukey test (p<5%) RESULTS: showed statistical differences among the groups. CONCLUSIONS: The previous plaster drying influenced the residual monomer amount showing a decrease of these levels.

Assessment of the flexural strength of two heat-curing acrylic resins for artificial eyes

Fernandes,Aline Úrsula Rocha; Portugal,Aline; Veloso,Letícia Rocha; Goiato,Marcelo Coelho; Santos,Daniela Micheline dos
Fonte: Sociedade Brasileira de Pesquisa Odontológica - SBPqO Publicador: Sociedade Brasileira de Pesquisa Odontológica - SBPqO
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2009 EN
Relevância na Pesquisa
69.084604%
Prosthetic eyes are artificial substitutes for the eyeball, made of heat-curing acrylic resin, serving to improve the esthetic appearance of the mutilated patient and his/her inclusion in society. The aim of this study was to assess the flexural strength of two heat-curing acrylic resins used for manufacturing prosthetic eyes. Thirty-six specimens measuring 64 x 10 x 3.3 mm were obtained and divided into four groups: acrylic resin for artificial sclera N1 (Artigos Odontológicos Clássico, São Paulo, SP, Brazil), heat-cure water technique (GI) and microwave-cured (GII); colorless acrylic resin for prosthetic eyes (Artigos Odontológicos Clássico, São Paulo, SP, Brazil), heat-cure water technique (GIII) and microwave-cured (GIV). Mechanical tests using three point loads were performed in a test machine (EMIC, São José dos Pinhais, PR, Brazil). The analysis of variance and the Tukey test were used to identify significant differences (p < 0.01). Groups GII and GIV presented, respectively, the highest (98.70 ± 11.90 MPa) and lowest means (71.07 ± 8.93 MPa), with a statistically significant difference. The cure method used for the prosthetic eye resins did not interfere in their flexural strength. It was concluded that all the resins assessed presented sufficient flexural strength values to be recommended for the manufacture of prosthetic eyes.

Microbiological evaluation of peracetic acid for disinfection of acrylic resins

Stopiglia,Cheila Denise Ottonelli; Carissimi,Mariana; Scroferneker,Maria Lúcia; Fortes,Carmen Beatriz Borges
Fonte: Pontifícia Universidade Católica do Rio Grande do Sul Publicador: Pontifícia Universidade Católica do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2011 EN
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PURPOSE: The aim of this study was to assess the efficacy of peracetic acid (PAA) for the disinfection of dental acrylic resins experimentally contaminated with Candida albicans, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. METHODS: Fifteen materials were used for each type of resin (thermosetting, self-curing and microwave-curing). Each material was placed in a test tube containing culture medium with a suspension of each microorganism and then incubated. The materials were rinsed and transferred to other tubes containing 50 mL of water for 5 min, 0.2% peracetic acid for 5 min or glutaraldehyde for 30 min. The materials were placed in the culture agar and incubated. Microbial growth was determined by colony counting after plating. RESULTS: Candida albicans growth was inhibited by peracetic acid and glutaraldehyde treatments. The number of colonies on resins treated with saline was greater than 10(5) CFU/mL. In resins infected with E. coli, S. aureus and P. aeruginosa the colony growth was not inhibited by saline and peracetic acid, but it was totally inhibited by glutaraldehyde. CONCLUSION: Surface disinfection using peracetic acid effectively inhibited C. albicans growth on all acrylic resins.

Surface morphology changes of acrylic resins during finishing and polishing phases

Serra,Glaucio; Morais,Liliane Siqueira de; Elias,Carlos Nelson
Fonte: Dental Press International Publicador: Dental Press International
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2013 EN
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INTRODUCTION: The finishing and polishing phases are essential to improve smoothness and shining on the surface of acrylic resins used to make removable orthodontic appliances. A good surface finishing reduces roughness, which facilitates hygiene, prevents staining and provides greater comfort to the patients. OBJECTIVE: The aim of this paper was to analyze the changes on surface morphology of acrylic resins during finishing and polishing phases. METHODS: Thirty discs (10 mm in diameter and 5 mm in length) were made with acrylic resin and randomly divided into ten groups. The control group did not receive any treatment while the other groups received gradual finishing and polishing. The last group received the entire finishing and polishing procedures. Surface morphology was qualitatively analyzed through scanning electron microscopy and quantitatively analyzed through a laser profilometer test. RESULTS: The acrylic resin surfaces without treatment showed bubbles which were not observed in the subsequent phases. Wearing out with multilaminated burs, finishing with wood sandpaper and finishing with water sandpaper resulted in surfaces with decreasing irregularities. The surfaces that were polished with pumice and with low abrasive liquids showed high superficial smoothness. CONCLUSION: Highly smooth acrylic resin surfaces can be obtained after mechanical finishing and polishing performed with multilaminated burs...

Mass loss of four commercially available heat-polymerized acrylic resins after toothbrushing with three different dentifrices

FREITAS-PONTES, Karina M.; SILVA-LOVATO, Cláudia H.; PARANHOS, Helena F. O.
Fonte: Faculdade De Odontologia De Bauru - USP Publicador: Faculdade De Odontologia De Bauru - USP
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
69.0178%
The association between a toothbrush and a dentifrice is the most used denture cleaning method. The purpose of this study was to evaluate the abrasiveness of specific and non-specific denture cleaning dentifrices on different heat-polymerized acrylic resins. Sixteen specimens (90x30x3mm) of each acrylic resin (QC-20, Lucitone 550, Clássico, Vipi-Cril) were prepared and randomly assigned to 4 groups: 1: control (distilled water), 2: Colgate, 3: Bonyplus and 4: Dentu-Creme. The specimens were subjected to simulated toothbrushing in an automatic brushing machine using 35,600 brush strokes for each specimen. Brushing abrasion run at a 200-g load with the specimens immersed in 2:1 dentifrice/water slurry. Specimens were reconditioned to constant mass and the mass loss (mg) was evaluated. Data were analyzed by 2-way ANOVA and Tukey's test (a=0.05). Analysis of dentifrices' abrasive particles was made by scanning electron microscopy. Colgate produced the greatest mass reduction (42.44 mg, p<0.05), followed by Dentu-Creme (33.60 mg). Bonyplus was the less abrasive (19.91 mg), similar to the control group (19.69 mg) (p>0.05). The mass loss values indicated that QC-20 (33.13 mg) and Lucitone 550 (33.05 mg) resins were less (p<0.05) resistant to abrasion than Clássico (26.04 mg) and Vipi-Cril (23.43 mg). In conclusion...

Mass loss of four commercially available heat-polymerized acrylic resins after toothbrushing with three different dentifrices

Freitas-Pontes,Karina M.; Silva-Lovato,Cláudia H.; Paranhos,Helena F. O.
Fonte: Faculdade De Odontologia De Bauru - USP Publicador: Faculdade De Odontologia De Bauru - USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2009 EN
Relevância na Pesquisa
69.0178%
The association between a toothbrush and a dentifrice is the most used denture cleaning method. The purpose of this study was to evaluate the abrasiveness of specific and non-specific denture cleaning dentifrices on different heat-polymerized acrylic resins. Sixteen specimens (90x30x3mm) of each acrylic resin (QC-20, Lucitone 550, Clássico, Vipi-Cril) were prepared and randomly assigned to 4 groups: 1: control (distilled water), 2: Colgate, 3: Bonyplus and 4: Dentu-Creme. The specimens were subjected to simulated toothbrushing in an automatic brushing machine using 35,600 brush strokes for each specimen. Brushing abrasion run at a 200-g load with the specimens immersed in 2:1 dentifrice/water slurry. Specimens were reconditioned to constant mass and the mass loss (mg) was evaluated. Data were analyzed by 2-way ANOVA and Tukey's test (a=0.05). Analysis of dentifrices' abrasive particles was made by scanning electron microscopy. Colgate produced the greatest mass reduction (42.44 mg, p<0.05), followed by Dentu-Creme (33.60 mg). Bonyplus was the less abrasive (19.91 mg), similar to the control group (19.69 mg) (p>0.05). The mass loss values indicated that QC-20 (33.13 mg) and Lucitone 550 (33.05 mg) resins were less (p<0.05) resistant to abrasion than Clássico (26.04 mg) and Vipi-Cril (23.43 mg). In conclusion...

Impact strength of denture base and reline acrylic resins subjected to long-term water immersion

Wady,Amanda Fucci; Machado,Ana Lucia; Vergani,Carlos Eduardo; Pavarina,Ana Cláudia; Giampaolo,Eunice Teresinha
Fonte: Fundação Odontológica de Ribeirão Preto Publicador: Fundação Odontológica de Ribeirão Preto
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2011 EN
Relevância na Pesquisa
68.9253%
Water may influence the mechanical properties of the acrylic resins. Thus, the effect of water storage on the impact strength (IS) of one denture base (Lucitone 550 - L) and four reline resins (Tokuyama Rebase II - T; UfiGel Hard - U; Kooliner - K; New Truliner - NT) was evaluated. Bars of L were made (60 x 6 x 2 mm) and relined (2 mm) with T, U, K, NT and L. Intact specimens of each material (60 x 6 x 4 mm) were also fabricated for comparative purposes. Specimens were submitted to Charpy impact tests without water storage (control) and after immersion in water for 7, 90 and 180 days. Data (kJ/m²) analyzed by two-way ANOVA and Tukey's test (p=0.05) revealed that after 90 days, U exhibited an increase in the IS (0.93) compared to 7 days (0.58). K (1.48) and L/K (7.21) exhibited a decrease at the 7-day period (1.01 and 3.23, respectively). NT (0.60) showed an increase in the IS after 180 days (1.52), whereas L/NT (7.70) showed a decrease (3.17). Water immersion improved the IS of U and NT, and decreased the IS of K, L/K, and L/NT. Water may affect differently the IS of acrylic resins and, consequently, the resistance to fracture of relined denture bases.

In vitro cytotoxicity of self-curing acrylic resins of different colors

Retamoso,Luciana Borges; Cunha,Taís de Morais Alves da; Pithon,Matheus Melo; Santos,Rogério Lacerda dos; Martins,Fernanda Otaviano; Romanos,Maria Teresa Villela; Tanaka,Orlando Motohiro
Fonte: Dental Press International Publicador: Dental Press International
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2014 EN
Relevância na Pesquisa
69.13959%
OBJECTIVE: The aim of this study was to assess the in vitro cytotoxicity of acrylic resins of different colors over time. METHODS: Specimens were divided into 4 groups (n = 6) according to the color of the acrylic resin (Orto Class, Clássico, Campinas, São Paulo, Brazil): Group 1: clear acrylic resin; group 2: pink acrylic resin; group 3: blue acrylic resin and group 4: green acrylic resin. All specimens were fabricated according to the mass manipulation technique and submitted to mechanical polishing protocol. The control was performed with an amalgam specimen (C+), a glass specimen (C-) and cell control (CC). Specimens were immersed in Minimum Eagle's Medium (MEM) and incubated for 24 h at 37o C. The extracts from the experimental material were filtered and mixed with L929 fibroblast. Cytotoxicity was evaluated at 4 different times, 24, 48, 72 and 168 h. After contact, cells were incubated for 24 h and added to 100 µ of 0.01% neutral red dye. The cells were incubated for 3 h for pigment incorporation and fixed. Cells viability was determined by a spectroscopic (BioTek, Winooski, Vermont, USA) with a 492-nm wavelength λ=492 nm). RESULTS: There were no statistical differences between the experimental groups and the CC and C- groups. CONCLUSION: Clear...

Influence of plaster drying on the amount of residual monomer in heat-cured acrylic resins

Paes-Junior, Tarcisio José de Arruda; Carvalho, Rodrigo Furtado de; Cavalcanti, Sâmia Carolina Mota; Saavedra, Guilherme de Siqueira Ferreira Anzaloni; Borges, Alexandre Luiz Souto
Fonte: UNICAMP/FOP Publicador: UNICAMP/FOP
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ;
Publicado em 16/10/2015 POR
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68.92486%
Aim: To evaluate the influence of plaster condition, dry or not, on the amount of residual monomer in heat-cured acrylic resin. Methods: Thirty acrylic resin specimens (65x10x3 mm) were fabricated and randomly assigned to 5 groups (n=6). The evaluated resins were heat-cured acrylic resins by conventional or microwave polymerization techniques and the plaster was previously dried in microwave oven in two groups. Each specimen was individually immersed in a test tube containing methanol (7 days) for surface analysis. In the groups for which internal monomer was evaluated, the specimens were fragmented and the small fragments were weighed prior to immersion in methanol. The analysis was made by high performance liquid chromatography (HPLC). Data were analyzed by ANOVA and Tukey test (p<5%) Results: showed statistical differences among the groups. Conclusions: The previous plaster drying influenced the residual monomer amount showing a decrease of these levels.

; Assessment of flexural strength of two self-curing acrylic resins containing pigment

Telles, Vicente; Brito, Raphael M. F.; Jurach, Estela M.; Nojima, Lincoln I.
Fonte: UNICAMP/FOP Publicador: UNICAMP/FOP
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; Formato: application/pdf
Publicado em 04/12/2015 ENG
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; Aim: To assess the flexural strength of orthodontic acrylic resins from two different manufacturers (VIPI, OrtoCril versus Clássico, OrtoClas) by comparing pigmented resins to colorless ones. Methods: Resins of blue, yellow and green colors were studied. A total of 120 specimens were made and then divided into groups of 15 elements each, all having the same dimensions. Next, they were kept in aqueous medium until being subjected to mechanical testing. The flexural strength was tested in a universal test machine (EMIC DL 10000) in which the specimens were subjected to a gradual load until fracture occurred. Results: Pigmented resins had flexural strength values compatible with clinical use, being similar to those from colorless ones, except for OrtoClas green-colored and yellow-colored resins, which showed greater flexural strength. The OrtoClas green-colored resin was the most resistant to fracture (482.2 N), whereas the OrtoCril colorless resin was the least resistant (368.4 N). All OrtoClas resins showed higher strength values compared to OrtoCril resins of same color, except for the OrtoCril’s blue-colored resin, which presented higher flexural strength than that of the other trademark. Conclusions: The use of pigments seems to have no effect on decreasing the flexural strength of self-curing acrylic resins. Therefore...