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Doctoral Thesis
DOI
https://doi.org/10.11606/T.23.2021.tde-30082021-093901
Document
Author
Full name
Sandra Barbosa Moraes de Almeida
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2021
Supervisor
Committee
Medeiros, Igor Studart (President)
Reis, Andréa Candido dos
Francci, Carlos Eduardo
Noronha Filho, Jaime Dutra
Title in Portuguese
Influência da composição monomérica e do pré-aquecimento na viscosidade, grau de conversão, propriedades mecânicas e ópticas de resinas compostas experimentais
Keywords in Portuguese
Cimentação
Pré-aquecimento
Propriedades mecânicas
Propriedades ópticas
Resinas compostas
Abstract in Portuguese
O presente trabalho avaliou a espessura de película, o grau de conversão (GC), propriedades mecânicas e propriedades ópticas de 5 resinas compostas experimentais com variações de tipos e proporção de monômeros e conteúdo constante de carga de vidro de bário de 0,7 µm e 5 resinas compostas comerciais [Estelite Omega (Tokuyama) , Filtek Z 100 (3M ESPE), Filtek Z 350 (3M ESPE), Empress Direct (Ivoclar Vivadent) e Vittra APS (FGM)] pré-aquecidas nas temperaturas de 30°C, 45°C, 60°C e 75°C e na temperatura ambiente (TA) (controle = 24°C). O pré-aquecimento (PA) das resinas, a confecção dos corpos de prova (CP) e o teste de espessura de película foram feitos com o auxílio de uma caixa aquecedora em condição controlada de temperatura (isotermia). As medidas de espessura de películas foram feitas por um método adaptado da ISO 4049, previamente validado. A espessura de película obtida após polimerização foi medida em paquímetro de precisão de 1 µm. O grau de conversão (GC) foi medido por FTIR em dois momentos: após 1 hora e após 24 horas da polimerização. O teste de resistência à flexão biaxial (RFB) foi feito em máquina de ensaios universal; a microdureza Knoop (KHN) em microdurômetro; as leituras de cor para cálculos de diferença de cor (?E), razão de contraste (RC) e parâmetro de translucidez (PT) em espectrofotômetro. Os resultados foram normais e homocedásticos, submetidos a ANOVA de um fator com nível de significância de 5% e teste post hoc de Bonferroni. A espessura de película das resinas experimentais reduziu com o PA, mas as resinas comerciais foram marcadependentes. O PA aumentou o GC de todas as resinas experimentais e da resina Estelite na leitura de 1 hora; na leitura após 24 horas as resinas experimentais tiveram respostas variadas e para as resinas comerciais não houve diferença entre as diferentes temperaturas de PA. A RFB de resinas experimentais e comerciais aumentou pontualmente entre materiais e temperaturas, enquanto a KHN aumentou em todos os materiais em função do PA. O ?E foi medido pelos métodos CIELab (?Eab) e CIEDE 2000 (?E00), que apresentaram correlação de Pearson >= 0,83. Para a maioria das resinas experimentais, o PA aumentou o ?E comparada ao controle (24°C); entre as resinas comerciais as respostas variaram entre aumento e redução do ?E em função do PA. As variações de ?E foram acompanhadas por deslocamentos dos eixos a* e b*. A razão de contraste (RC) variou entre os materiais e temperaturas e o parâmetro de translucidez (PT) não variou com o PA. A partir dos dados obtidos, conclui-se que o PA favoreceu as resinas experimentais na redução da espessura de película, GC em 1 hora e KHN, porém aumentou o ?E e não alterou o PT. Para as resinas comerciais apenas a KHN aumentou com o PA; as demais propriedades foram marca-dependentes.
Title in English
Influence of monomeric composition and preheating on viscosity, degree of conversion, mechanical and optical properties of experimental composite resins
Keywords in English
Luting
Mechanical properties
Optical properties
Preheating
Resin composites
Abstract in English
The present work evaluated the film thickness, the degree of conversion (DC), mechanical properties and optical properties of 5 experimental composite resins with variations of types and proportion of monomers and constant load content of 0.7 µm barium glass and 5 commercial composite resins [Estelite Omega (Tokuyama), Filtek Z 100 (3M ESPE), Filtek Z 350 (3M ESPE), Empress Direct (Ivoclar Vivadent) and Vittra APS (FGM)] preheated to 30°C, 45°C, 60°C and 75°C and at room temperature (RT) (control = 24°C). The preheating (PH) of the resins, the making of the specimens (SP) and the film thickness (FT) test were done with the aid of a heating box in a controlled temperature condition (isotherm). Film thickness measurements were made using a method adapted from ISO 4049, previously validated. The film thickness obtained after polymerization was measured using a 1 µm precision caliper. The degree of conversion (DC) was measured by FTIR at two times: after 1 hour and after 24 hours of polymerization. The biaxial flexural strength test (BFS) was performed on a universal testing machine; the microhardness Knoop (KHN) in microdurometer; the color readings for calculations of color difference (?E), contrast ratio (CR) and translucency parameter (TP) in a spectrophotometer. The results were normal and homoscedastic, submitted to one-way ANOVA with a 5% significance level and Bonferroni's post hoc test. The film thickness of the experimental resins decreased with PH, but commercial resins were brand dependent. The PH increased the DC of all experimental resins and Estelite resin in the 1-hour reading; in reading after 24 hours the experimental resins had varied responses and for commercial resins there was no difference between the different PH temperatures. The BFS of experimental and commercial resins increased occasionally between materials and temperatures, while KHN increased in all materials due to the PH. ?E was measured by CIELab (?Eab) and CIEDE 2000 (?E00) methods, which showed Pearson's correlation >= 0.83. For most experimental resins, PH increased ?E compared to control (24°C); among commercial resins the responses varied between increasing and decreasing ?E as a function of PH. Variations in ?E were accompanied by shifts in axes a * and b *. The contrast ratio (CR) varied between materials and temperatures and the translucency parameter (TP) did not vary with the PH. From the data obtained, it is concluded that the PH favored the experimental resins in reducing the film thickness, DC in 1 hour and KHN, however it increased the ?E and did not change the TP. For commercial resins only KHN increased with PH; the other properties were brand dependent.
 
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Publishing Date
2021-09-17
 
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