Bonding Degradation of IPS Empress Esthetic bonded with different agents

OBJECTIVES: to evaluate the effect of storage time (24 h and 6 months) in the µTBS of the bovine dentin/ceramic IPS Empress Esthetic bonding with different resinous cement associated or no with adhesive system. METHODS: Thirty bovine incisors were ground flat with 120- and 600-grit SiC papers reaching dentin. Thirty ceramics IPS Empress Esthetic blocks were made (10mm x 8mm x 2.5mm) and divided in 3 groups (n=10): G1 - DSC Excites +Variolink II; G2 - RelyX UNICEM (without treatment); G3 - RelyX UNICEM+Adper Prompt. Ceramic surface treatment was accomplished with 10% fluoridric acid per 20 seconds and silane application. Then, the ceramics were bonded to dentin using the three group treatments. After excesses removal the resinous cement was light cured per 20 seconds in all sides of the specimen, totalizing 80 seconds of exposition with LED-UltraLume 5, with 1100 mW/cm2 and stored in distilled water 37º C for 24 hours. Then, sticks were obtained with 1mm2 sectional area (60 sticks per group). After that, 30 sticks of each group were stored in distilled water for 24 hours 37º C and 30 sticks for 6 months. The sticks were submitted to the µTBS at Instron machine with 0.5 mm/min speed. Data were submitted to ANOVA and Tukey tests (5%). RESULTS: After 24-hour storage no significant difference was observed among the groups. After 6-month storage there was a decrease in the µTBS values for cements associated to the adhesive systems. After 6 month-storage RelyX UNICEM without adhesive system showed the highest values. 24-hour storage showed cohesive failure and 6 months storage adhesive ones for cements associated with adhesive systems and cohesive failure for RelyX UNICEM with no adhesive. CONCLUSION: 6-month water storage played a significant role to reduce the µTBS for resinous cement used with adhesive systems.