Resistência de união cerâmica - agente cimentante. Teste de micro-tração e análise por microscopia eletrônica de varredura
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Data
2004-12-02
Autores
Faria, Ricardo Pinheiro de [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os objetivos deste trabalho foram avaliar a influência de diferentes tempos de condicionamento ácido na resistência de união cerâmica-agente cimentante, por meio do teste de Micro-Tração, bem como análise dos modos de fratura. Foram confeccionados 5 pares de discos de cerâmica de infra-estrutura IPS Empress 2 e divididos aleatoriamente em 5 grupos. As superfícies de união foram regularizadas através de desgaste com lixas abrasivas de granulação seqüencial sob refrigeração. Os espécimes foram nomeados ao acaso e submetidos aos seguintes tratamentos antes da cimentação: G1: sem condicionamento ácido; G2: 20 s de condicionamento com ácido fluorídrico a 10%; G3: 40 s e condicionamento com ácido fluorídrico a 10%; G4: 60 s de condicionamento com ácido fluorídrico a 10% e G5: 2 min de condicionamento com ácido fluorídrico a 10%. Os espécimes, aos pares, foram cimentados com um sistema adesivo e cimento resinoso dual, de acordo com as recomendações do fabricante. Espécimes foram fotopolimerizados, armazenados por 48 h a 37°C e, posteriormente, com auxílio de um disco de diamante perpendicular à superfície de união, palitos com 1 mmø de área de seção foram obtidos. Os valores de resistência de união (MPa) foram obtidos com auxílio de uma máquina de teste universal (MTS 800) e submetidos à análise de variância e teste de Tukey. As médias de resistência foram de 30,20 MPa, 36,19 MPa, 38,72 MPa, 41,43 MPa e 42,53 MPa, respectivamente aos grupos G1, G2 G3 G4 e G5. O grupo G1 apresentou menor resistência média de união do que os demais grupos. O grupo G3 teve comportamento semelhante a G2 e a G4, porém estes dois últimos foram diferentes entre si. Os grupos G4 e G5 promoveram resistências médias semelhantes. Concluímos que o aumento do tempo de condicionamento ácido aumentou os valores de resistência de... .
The purpose of this study was to investigate the effect of different times of acid conditioning on the microtensile bond strength between union-cement and ceramic, and to verify the mode of failure. Five pairs of ceramic disks (IPS Empress 2) were divided, in five groups, by randomized allocation. The bonding surfaces were finished with 600-grit silicon carbide paper. The specimens were nominated at random and submitted to the following treatments before cementation: G1 : without acid etching; G2 : 20 s of etching with 10% hydrofluoric acid; G3 : 40 s of etching with 10% hydrofluoric acid; G4 : 60 s of etching with 10% hydrofluoric acid and G5 : 2 min of etching with 10% hydrofluoric acid. All the pairs were bonded with dual cure resin bonding and dual cure resin cement, according to manufacturer's instructions. The specimens were light-cured and then stored for 48 h at 37°C. Using a diamond disk perpendicular to the bonding interface, 'sticks' with 1.0 mmø cross-sectional area were obtained. Microtensile bond strengths were determined using a MTS 800 Materials Testing Machine at a crosshead speed of 0.5 mm/min. It was applied analysis of variance and Tukey test at p<0.05. The means of microtensile bond strength, in MPa, were 30.20, 36.19, 38.72, 41.43 and 42.53, respectively to the groups G1, G2, G3, G4 and G5. Group G1 had the smallest microtensile bond strength and G3 had similar results when compared to G2 and G4, although G2 and G4 were different between themselves. The groups G4 and G5 showed similar means of microtensile bond strength. Conclusions: The higher the time of acid conditioning higher were the values of microtensile bond strength, and the analysis of mode of failure exhibited prevalence of adhesive failure type.
The purpose of this study was to investigate the effect of different times of acid conditioning on the microtensile bond strength between union-cement and ceramic, and to verify the mode of failure. Five pairs of ceramic disks (IPS Empress 2) were divided, in five groups, by randomized allocation. The bonding surfaces were finished with 600-grit silicon carbide paper. The specimens were nominated at random and submitted to the following treatments before cementation: G1 : without acid etching; G2 : 20 s of etching with 10% hydrofluoric acid; G3 : 40 s of etching with 10% hydrofluoric acid; G4 : 60 s of etching with 10% hydrofluoric acid and G5 : 2 min of etching with 10% hydrofluoric acid. All the pairs were bonded with dual cure resin bonding and dual cure resin cement, according to manufacturer's instructions. The specimens were light-cured and then stored for 48 h at 37°C. Using a diamond disk perpendicular to the bonding interface, 'sticks' with 1.0 mmø cross-sectional area were obtained. Microtensile bond strengths were determined using a MTS 800 Materials Testing Machine at a crosshead speed of 0.5 mm/min. It was applied analysis of variance and Tukey test at p<0.05. The means of microtensile bond strength, in MPa, were 30.20, 36.19, 38.72, 41.43 and 42.53, respectively to the groups G1, G2, G3, G4 and G5. Group G1 had the smallest microtensile bond strength and G3 had similar results when compared to G2 and G4, although G2 and G4 were different between themselves. The groups G4 and G5 showed similar means of microtensile bond strength. Conclusions: The higher the time of acid conditioning higher were the values of microtensile bond strength, and the analysis of mode of failure exhibited prevalence of adhesive failure type.
Descrição
Palavras-chave
Ceramica, Cimentos dentarios, Resistência à tração, Ceramics, Dental cements, Tensile strength
Como citar
FARIA, Ricardo Pinheiro de. Resistência de união cerâmica - agente cimentante. Teste de micro-tração e análise por microscopia eletrônica de varredura. 2004. 144 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Odontologia de Araraquara, 2004.