Influence of 3-month simulated pulpal pressure on the microtensile bond strength of simplified resin luting systems

Purpose: To assess the influence of simulated pulpal pressure (SPP) on the microtensile bond strength (μTBS) of four simplified luting strategies to indirect composite restorations. Materials and Methods: 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). Results: 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). Conclusions: 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.