Influence of etching time and adhesive system on shear bond strength and compression resistance of the reinforced leucite ceramic

• Ano de defesa: 2019
• Autor(a) principal: Libardi, Camila Cruz
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Ceramics; Compressive strength; Hydrofluoric acid; Shear bond strength
• Link de acesso: http://www.teses.usp.br/teses/disponiveis/25/25148/tde-05092019-205033/

This in vitro study evaluated the bond and compression strength of cemented leucite reinforced glass ceramics in bovine tooth enamel, comparing three etching times with hydrofluoric acid 10% of the ceramic surface (20, 60 and 90 seconds) and two adhesive treatments (adhesive system + silane and universal adhesive system). For the bond strength test, 120 ceramic cylinders (2mm diameter x 2mm length; n=20) were etched and cemented (80m thick) in enamel with a dual resin cement, varying the adhesive treatment, obtaining the groups: UEXC20s, UEXC60s, UEXC90s, USBU20s, USBU60s, USBU90s. After 24 hours, the shear bond strength test was performed on a universal test machine (0.5mm/min, 50kgf). For the compression test, 30 ceramic plates (5x5mm with 1mm thick, n=5) were etched, received the same adhesive treatments and were cemented (80m) in enamel, obtaining the following groups: CEXC20s, CEXC60s, CEXC90s, CSBU20s, CSBU60s, CSBU90s. After 24 hours of cementation, the compression test (0.5mm/min, 500kgf) was performed. Statistical analysis was performed using two-way ANOVA and Tukey test (=.05). For the shear bond strength test significant differences were found among the adhesives (p<.05). For the etching times there were no differences (p=.059). However, there was a significant interaction between the adhesives and the etching times (p=.021). At 60 seconds, the Silane + ExciTE F DSC Adhesive presented the highest bond strength values (47.53±16.70Mpa). And at 20 seconds, the Universal adhesive presented the lowest bond strength values (27.72±10.76Mpa). For the compression test there were no significant differences between the adhesives (p=.571) and between the times (p=.154). The group that presented the highest values of compression force was the Universal adhesive at 60 seconds (1757.89±200.47N). The lowest values were also the Universal adhesive, but at 90 seconds (1213.30±546.34N). The study concluded that the silane associated with the ExciTE F DSC adhesive showed the highest bond strength values at the etching time of 60 seconds with 10% hydrofluoric acid, without compromising the compressive strength of the leucite reinforced ceramic.