Influência do substrato, cimento e envelhecimento na resistência a flexão biaxial do dissilicato de lítio

• Autor(a) principal: Lima, Leonardo Custódio de [UNESP]
• Data de Publicação: 2017
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/156568; http://www.athena.biblioteca.unesp.br/exlibris/bd/capelo/2018-05-10/000899673.pdf
• topic: Cerâmica; Lítio; Cimentação; Envelhecimento

The aim of this research was to evaluate the biaxial flexural strength of a lithium disilicate ceramic (LD) cemented in different substrates (epoxy resin - G; or metal - M) with different cements (resin cement - P; or zinc phosphate - Z), whether or not subjected to thermal aging (E). Eight groups were made (n=10): PG (LD+P+G); PM (LD+P+M); ZM (LD+Z+M); ZG (LD+Z+G); PGE (LD+P+G+E); PME (LD+P+M+E); ZME (LD+Z+M+E); ZGE (LD+Z+G+E). The metal disks were all blasted with aluminum oxide. The DL and G discs intended for adhesive cementation were conditioned with hydrofluoric and phosphoric acid respectively. The luting process was performed with the aid of a standardized device with a 750g load. The biaxial bending test was performed with a universal test machine with a load cell of 1000KgF at a speed of 1mm min until some type of failure was detected. A specimen of each material (LD, M and G) with and without surface treatment were evaluated by scanning electron microscopy. The three-factor ANOVA and Tukey tests revealed a significant effect of substrate (p=0,000) and aging (p=0,02), significant interaction between substrate/aging (p=0.03) and cement/aging (p=0.047), but there was no significant interaction between the three factors (p=0.071). The highest values of resistance in MPa were found in the groups ZM (459,80), PM (353,50), PME (287,10), ZME (193,80), followed by PG (60,20), PGE (59,69), ZG (54,64) and ZGE (44,49). The microscopy images revealed a change in the topography of the materials after the surface treatments performed. It can be concluded that the substrate and aging significantly modified the resistance of lithium disilicate to the bending test. However, the cement type did not show significant difference between the groups, since, depending on the substrate, the cementing agent presented a different behavior