Influence of 3-month Simulated Pulpal Pressure on the Microtensile Bond Strength of Simplified Resin Luting Systems.

To assess the influence of simulated pulpal pressure (SPP) on the microtensile bond strength (μTBS) of four simplified luting strategies to indirect composite restorations. Dentin disks from 40 human molars were prepared and treated with 4 different techniques: (1) SB+ARC: two-step etch-and-rinse adhesive + conventional dual-curing resin cement (Adper Single Bond 2 + RelyX ARC, 3M ESPE); (2) ED+PAN: self-etching primer + conventional dual-curing resin cement (ED Primer + Panavia F2.0, Kuraray Medical); (3) S3+PAN: one-step self-etching adhesive (Clearfil S3, Kuraray) + Panavia F2.0; (4) U200: self-adhesive resin cement (RelyX U200, 3M ESPE). Pre-made indirect composite restorations (Filtek Z100, 3M ESPE) were luted onto the specimens. The luted specimens were cut into resin-dentin beams and the μTBS was tested after two different aging regimes: water storage at 37°C for one week (control) or three months under 20 cm H2O simulated pulpal pressure (SPP). The μTBS data was analyzed with two-way ANOVA and Tukey's test (p < 0.05). SB+ARC showed significantly higher μTBS after both aging regimes (p < 0.001). The statistically significantly lowest μTBS was measured for control S3+PAN and U200 after 3 months SPP (p < 0.001). S3+PAN was the only group not negatively affected by SPP (p = 0.699). Two-step etch-and-rinse adhesives associated with dual-curing conventional resin cements may achieve the highest μTBS, even after 3 months of SPP. The one-step self-etching adhesive along with the dualcuring conventional resin cement was able to maintain bond stability.