Efeito da presença do MDP no silano e/ou adesivo universal em protocolos de cimentação de diferentes cerâmicas de disilicato de litio

Abstract

The aim of this in vitro study was to evaluate the effect of a silane and an adhesive containing MDP, used alone or in combination, on indirect restorative materials on the microshear bond strength (μSBS) at two times, 24 h of storage in water and after thermal aging. A total of 54 blocks of four CAD/CAM materials were selected: 1) IPS e.max CAD (EMX), as lithium disilicate ceramic; 2). VITA Suprinity (SUP), and 3). Celtra Duo (CEL), as zirconia-reinforced lithium disilicate ceramics. For each material, 18 blocks were used and processed as recommended by the manufacturer. Then they were divided into 3 experimental conditions (n=6) according to: a). silane with MDP (MNB; Monobond N; Ivoclar Vivadent); b). adhesive with MDP (TBU; Tetric N Bond Universal; Ivoclar Vivadent); and c). silane with MDP + adhesive with MDP in combination (MNB/TBU). Transparent cylinder-shaped matrices were filled with resin cement (Variolink N Esthetic; Ivoclar Vivadent) and light-cured. The specimens were stored in water (37°C/24h), and tested in a universal testing machine (1.0 mm/min) in immediate form and after 10,000 thermal cycles, the specimens were subjected to the microshear test at a speed of 1 mm/min until failure. The failures were observed in the optical microscope at 100x magnification and evaluated in scanning electron microscopy (FEG) at a magnification of 150x. Additionally the ceramics were subjected to energy dispersive spectrometry (EDS) testing to evaluate their elemental composition, and Raman chemical interaction testing. The Two Way ANOVA statistical test was preset with a significance of α= 0.05 and as a result the application of only one silane containing MDP showed statistically higher results compared to the TBU and MNB/TBU group (p < 0.05), both in the immediate time and after thermocycling. The bond strength under all three types of ceramics was significantly affected by the adhesive system used. Thus using only silane it is possible to obtain durable adhesion for lithium disilicate.