Influência de diferentes protocolos de cimentação na resistência de união em cerâmicas com diferentes composições

Abstract

The objective of this in vitro work was to evaluate a micro-shear strength (μSBS) of ceramics with different degrees of translucency and cementing agents,on immediate time and after simulation of 1 year of aging in thermocycling, as well as to evaluate the elemental composition do to the dispersive energy spectrometry (EDS) test. Four ceramics were selected: Lithium Dissilicate (DL), Prettau Anterior (PA), Prettau (PR) and ICE (CI). The ceramic specimens were distributed in 16 experimental groups (n = 5) depending on the combination of variables: ceramic vs. surface treatment (silane-SL or silane + adhesive-AS) vs. storage time (immediate and longevity) vs. resin cement Brochure Variolink II or Variolink). The zirconia ceramics were subjected to blasting with aluminum oxide and the lithium disilicate ceramic with fluoridric acid 5% per 20s. After the surface treatment according to each experimental group, tygon tubes were placed on the ceramic surface and filled with resin cement. After 24 hours in an oven at 37ºC and after 10.000 thermal cycles, the specimens were submitted to the micro-shear test at a speed of 1mm / min until failure. Failures were observed in optical microscope in an increase of 100x, and evaluated in Scanning Electron Microscopy (FEG) with a magnification of 150x. Additionally, ceramics were submitted to the dispersive energy spectrometry (EDS) test to evaluate their elemental composition. For statistical purposes, it was chosen to divide the results into two experimental conditions:: one for Variolink II cement and another for Veneer. Thus, for each cement the μSBS data were subjected to the μSBS test (ANOVA 3-factor and Tukey, α = 0.05). For Variolink II cement, no significant triple interaction was found (p> 0.05). The double treatment vs time interaction (p <0.001) was significant, with immediate μSBS statistically higher values to distance. On the other hand, the double treatment versus ceramic interaction was statistically significant (p = 0.039), and the ceramics based on zirconia had higher values of bond strength, regardless of surface treatment. And the double time vs. ceramic interaction (p <0.001) showed a decrease of μSBS for all ceramics after the thermocycling. Variolink Veneer cement showed a significant triple interaction (p <0.001) for all groups. Regardless the surface treatment and ceramics, statistically, the highest values of resistance were found in the immediate time, and ceramics based on zirconia presented statistically higher values than lithium disilicate. It can be concluded that zirconia ceramics are more resistant to micro-shearing, on immediate time and after thermocycling; and that the AS association interferes positively with long-term results.