Avaliação de diferentes protocolos de cimentação de uma cerâmica YTZ-P vitrificada

Abstract

The purpose of this research is to evaluate the influence of conditioning time with hydrofluoric acid on the bond strength of a Y-TZP glazed ceramics and a resin cement. Ceramic pre-sintered Y-TZP blocks (IPS e.max® ZirCAD - Ivoclar Vivadent-) were cut to obtain 40 samples. Prior to sintering the blocks were smoothed with sandpaper water granulation #180, #600 and #1200. They were then randomly divided into four groups (n = 10), one control group was performed silicatization with Rocatec Soft (RS) and three vitrified test groups with different acid conditioning times surface: GS20s, GS60s and GS100s (application hydrofluoric acid for 20, 60 and 100 seconds respectively). For cementation was used a universal adhesive containing the MDP monomer in its composition (Single Bond Universal, 3M ESPE) and a dual resin cement (RelyX Ultimate, 3M ESPE). In each block was obtained two cement columns, totaling 20 samples per group. After thermocycling, the shear test was performed (EMIC, DL 2000), the maximum force to fracture was recorded and used to calculate the bond strength. Furthermore, the failure analysis was also performed with a esteriomicroscópio (Stemi 2000-C). An extra sample of each group had half of its surface treated to obtain images by profilometry and scanning electron microscopy (SEM), as well as conducting energy dispersive spectrometry (EDS). The Kruskal-Wallis test showed ap value of 0.001 and the Dunn test demonstrated differences only the RS group (22,10Mpa) for GS groups (GS20s: 8,10Mpa; GS60s: 10.49; GS100s: 7.53 ), but there was no difference among different GS groups. The profilometry and SEM images revealed an irregular pattern of glaze layout after conditioning with HF 10%. By profilometry it was possible to measure the thickness of the remaining glaze layer (GS20s: 5 ± 1μm; GS60s: 4 ± 1μm; GS100s: 3 ± 1μm). All failures were adhesive. And it concluded that the bond strength between Y-TZP glazed pottery and a resin cement with MDP is not influenced by different conditioning times with hydrofluoric acid.