Influência do agente cimentante e desajuste interno na adaptação marginal de coroas em resina nanocerâmica

Abstract

The marginal adaptation is one of the basic requirements for the longevity and success of restorations. The aim of this study was to evaluate the influence of the internal imbalances associated with different luting agents on marginal leakage of crowns Nanoceramic resin ( Lava Ultimate 3M ESPE ) made by CAD-CAM system. From the scanning of a full crown preparation in a pre molar were obtained 36 metal models. These were divided into six groups according to the internal imbalances (70 or 100 micrometres) and cement (SS White Zinc phosphate, glass ionomer cement Ketac Cem 3M / Espe and resinous cement Relyx Ultimate 3M / Espe). After scanning all models crowns were made from milling Nanoceramic resin blocks (Lava Ultimate 3M / Espe). With the aid of optical comparator microscope (40X) were measured prior marginal mismatches and after the cementation, being considered 8 points along the end in all specimen faces. The values were submitted to ANOVA two-way test and t test. Results showed that crowns made with internal imbalances of 70 uM show statistically significant lower marginal leakage to the crowns with internal imbalances of 100 micrometres. For the internal imbalances 70 uM zinc phosphate cement group showed the lowest gap marginal, and this figure does not show a statistically significant difference compared to Ketac Cem group. Even with this misfit, Ketac Cem group showed no statistically significant difference in relation to Relyx Ultimate group, though the latter showed a statistically significant difference compared to zinc phosphate cement group. For the internal imbalances of 100 micrometres there was no statistically significant difference in the gap marginal among the three cements. This study demonstrated through the methodology used, the lower marginal leakage observed in Lava Ultimate restorations, was from the inner misfit 70 micrometers. In this group the zinc phosphate cements and glass ionomer demonstrated better performance compared to the resin cement, although the glass ionomer cement numerically, but not statistically has presented results lower than that of zinc phosphate.