Immediate Dentin Sealing and Pulpal Pressure Effects on Cements µTBS

Objectives: To evaluate the effect of simulated pulpal pressure (SPP) and immediate dentin sealing technique (IDS) on the microtensile bond strength (µTBS) to dentin produced by different luting agents. Methods: Two self-adhesive luting agents ( RelyX U100 – UC and Clearfil SA Luting – SA) and 2 conventional luting agents (Rely X ARC – RX and Panavia F - PF) were used in this study. Eighty human molars were divided in 4 groups according to luting agents. Each group was sub-divided according to SPP and IDS using Clearfil SE Bond (n=5). After IDS was performed, sealed specimens were stored in water for 7 days before luting procedures. Cylindrical composite blocks were luted according to manufacturers' instructions. Half of the specimens were subjected to 15cm H2O of hydrostatic pressure for 24h before cementation procedures, and continued for 24h after luting procedures. Afterwards, restored teeth were serially sectioned into beams with a cross-sectional area of approximately 1mm2 at the bonded interface and were tested in tension (1mm/min). Failure mode was determined using scanning electron microscopy (SEM). Data were statistically analyzed by 3-way ANOVA and Tukey test. Results: the µTBS of RX decreased when it was subjected to SPP without IDS. However, in the same conditions µTBS of UC increased. The IDS prevented negative influence of SPP on µTBS of RX and PF, however a decrease on µTBS of SA and UC was observed. Except for RX, IDS increased µTBS for all resin cements. Conclusion: Independently of SPP, the IDS technique obtained higher µTBS to PF, SA and UC, and did not influence on µTBS of RX.(Grant: FAPESP 2008/07628-7, 2007/06083/4, 2009/16261-2, 2008/05179-0).