Effect of simulated pulpal pressure on self-adhesive cements bonding to dentin

Objectives To evaluate the bonding effectiveness of self-adhesive luting cements to dentin in the presence of simulated hydrostatic intrapulpal pressure (PP). Methods Thirty composite overlays (Aelite All Purpose Body) were luted to deep-coronal dentin surfaces using four self-adhesive resin cements (Rely X Unicem, G-Cem, Multilink Sprint, Bis-Cem) and one total-etch system (Calibra). Half of the specimens resin cements were applied under a PP of 15 cm H2O. After storage in a moist condition for 1 month (37 °C, 100% relative humidity), specimens were sectioned into microtensile beams (1 mm2) and stressed to failure with the microtensile bond strength test (μTBS). Data were statistically analyzed with Kruskal–Wallis ranking (p < 0.05) and Mann–Whitney tests (p < 0.001). The fracture pattern was evaluated under SEM. Results Bond strength of Calibra fell significantly when PP was applied during bonding (p < 0.05). Rely X Unicem and Bis-Cem performed better under PP. No significant differences for Multilink Sprint and G-Cem bonded specimens were recorded with or without PP. Significance Simulated PP influences the adhesive performance of resinous cements. The predominance of acid–base reactions or radical polymerization may explain the different behavior of self-adhesive cements when changing substrate wetness. The application of constant intrapulpal perfusion should be considered when simulating luting procedures in vitro.