Comparação de dois protocolos de tratamentos de superfície em cerâmicas cad/cam para cimentação adesiva

Abstract

The aim of this study was to evaluate, in vitro, the microtensile bond strength of two surface conditioning techniques in five types of CAD/CAM ceramics. Prefabricated CAD/CAM ceramic blocks (feldspathic, lithium silicate reinforced with zirconia, lithium disilicate, leucite and hybrid ceramic) were sectioned and the surfaces were polished with descending granules for surface standardization. All the ceramics received two different surface treatments: conventional technique (5% hydrofluoric acid followed by Monobond N) and simplified technique (Monobond Etch & Prime), then the Empress Direct composite resin was added respecting the incremental technique. The ceramic / resin set was stored, and the samples were then sectioned to form sticks with approximately 1mm² area, and were submitted to microtensile bond test. Data were analyzed using analysis of variance and Tukey's test (α=0.05) and were observed statistically significant difference between the groups (p=0.001). The conventional surface treatment technique resulted in a statistically higher bond strength for hybrid ceramic, however, for the lithium disilicate, statistically higher values were obteined with the simplified technique. The images obtained in AFM have evidenced that the surface conditioning pattern in the conventional technique shows to be more homogeneous and deep when compared to the simplified technique. In the data analysis, can be concluded that the simplified technique is feasible, since it presented results for bond strength similar to the conventional technique in feldspathic ceramics, lithium silicate reinforced with zirconia and leucite, and better results in lithium disilicate. However, for the hybrid ceramics obtained lower values, being able to affirm that the bond strength for the simplified technique depends on the type of ceramic used.